CHIRON CORP
10-Q, 1996-11-12
PHARMACEUTICAL PREPARATIONS
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<PAGE>

                                  UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                                       
                                   FORM 10-Q


(Check One)
          [X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
               SECURITIES EXCHANGE ACT OF 1934

                         OR

          [ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
               SECURITIES EXCHANGE ACT OF 1934

For Quarterly Period Ended September 29, 1996    Commission File Number: 0-12798

                              CHIRON CORPORATION
- --------------------------------------------------------------------------------
            (Exact name of registrant as specified in its charter)

     Delaware                                    94-2754624
- --------------------------------------------------------------------------------
(State or other jurisdiction of                  (I.R.S. Employer
incorporation or organization)                   Identification No.)

4560 Horton Street, Emeryville, California                  94608
- --------------------------------------------------------------------------------
(Address of principal executive offices)                    (Zip code)

                                (510) 655-8730
- --------------------------------------------------------------------------------
             (Registrant's telephone number, including area code)

                                Not Applicable
- --------------------------------------------------------------------------------
                    (Former name, former address and former
                  fiscal year, if changed since last report)

Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to
such filing requirements for the past 90 days.

                    Yes   X        No
                       --------      --------

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of the latest practicable date.

     Class                                   Outstanding at November 1, 1996
     -----                                   -------------------------------

Common Stock, $0.01 par value                       170,513,610 shares


<PAGE>


                              CHIRON CORPORATION
                               TABLE OF CONTENTS
- --------------------------------------------------------------------------------

                                                                      PAGE NO.
                                                                      --------
PART I.   FINANCIAL INFORMATION

     ITEM 1.  FINANCIAL STATEMENTS

          Consolidated Balance Sheets as of
          September 30, 1996 and December 31, 1995 ...................    3

          Consolidated Statements of Operations for the
          three months and nine months ended September 30,
          1996 and 1995 ..............................................    4

          Consolidated Statements of Cash Flows for the
          nine months ended September 30, 1996 and 1995 ..............    5

          Notes to Consolidated Financial Statements .................    6

     ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF
             FINANCIAL CONDITION AND RESULTS OF OPERATIONS ...........   18


PART II.  OTHER INFORMATION

     ITEM 1.  LEGAL PROCEEDINGS  .....................................   27

     ITEM 2.  CHANGES IN SECURITIES ..................................   27

     ITEM 3.  DEFAULTS UPON SENIOR SECURITIES ........................   27

     ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS ....   27

     ITEM 5.  OTHER INFORMATION  .....................................   27

     ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K .......................   27


SIGNATURES ...........................................................   39


                                       2

<PAGE>


                               CHIRON CORPORATION
                           CONSOLIDATED BALANCE SHEETS
                                 (IN THOUSANDS)
- --------------------------------------------------------------------------------
<TABLE>
<CAPTION>

                                                                     September 30,    December 31,
                                                                         1996             1995
                                                                     -------------    ------------
                                                                      (Unaudited)
<S>                                                                  <C>              <C>
                                     ASSETS
Current assets:
  Cash and cash equivalents                                            $  53,967      $  74,318
  Short-term investments in marketable debt securities                    45,080         61,066
                                                                     -----------      ---------
        Total cash and short-term investments                             99,047        135,384
  Accounts receivable                                                    340,358        285,779
  Inventories                                                            186,786        165,941
  Other current assets                                                    54,495         49,899
                                                                     -----------      ---------
        Total current assets                                             680,686        637,003
Noncurrent investments in marketable debt securities                      30,752         88,833
Property, plant, equipment and leasehold improvements, at cost:
  Land and buildings                                                     212,488        208,233
  Laboratory, production and office equipment                            365,864        292,828
  Leasehold improvements                                                 113,693         95,472
  Construction in progress                                                52,313         62,046
                                                                     -----------      ---------
                                                                         744,358        658,579
  Less:  accumulated depreciation and amortization                     (193,612)      (140,761)
                                                                     -----------      ---------
        Net property, plant, equipment and leasehold improvements        550,746        517,818
Purchased technology, net                                                 75,175         80,600
Other intangible assets, net                                              80,036         71,571
Investments in equity securities and affiliated companies                189,452         54,359
Other assets                                                              61,409         40,014
                                                                     -----------      ---------
                                                                    $  1,668,256   $  1,490,198
                                                                     -----------      ---------
                                                                     -----------      ---------

                      LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable                                                       $76,821        $81,081
  Accrued compensation and related expenses                               51,698         56,994
  Short-term borrowings                                                  137,178         50,036
  Current portion of unearned revenue                                     21,525         20,838
  Taxes payable                                                           34,281         27,551
  Other current liabilities                                              141,794        132,095
                                                                     -----------      ---------
        Total current liabilities                                        463,297        368,595
Long-term debt                                                           420,044        413,248
Other noncurrent liabilities                                              37,478         35,943
Commitments and contingencies
Stockholders' equity:
  Common stock                                                             1,700            417
  Additional paid-in capital                                           1,763,227      1,727,711
  Accumulated deficit                                                (1,047,823)    (1,087,699)
  Cumulative foreign currency translation adjustment                     (2,093)            721
  Unrealized gain from investments                                        32,426         31,262
                                                                     -----------      ---------
        Total stockholders' equity                                       747,437        672,412
                                                                     -----------      ---------
                                                                      $1,668,256     $1,490,198
                                                                     -----------      ---------
                                                                     -----------      ---------

</TABLE>

         THE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                  ARE AN INTEGRAL PART OF THIS STATEMENT.


                                        3

<PAGE>


                                CHIRON CORPORATION
                      CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (UNAUDITED)
                      (IN THOUSANDS, EXCEPT PER SHARE DATA)
- --------------------------------------------------------------------------------

<TABLE>
<CAPTION>


                                                                 Three Months Ended             Nine Months Ended
                                                           -----------------------------  ----------------------------
                                                           September 30,   September 30,  September 30,  September 30,
                                                                1996            1995         1996            1995
                                                           ------------    ------------   ------------   -------------
<S>                                                        <C>             <C>            <C>            <C>

Revenues:
 Product sales, net                                         $  240,530     $  230,311     $  729,877     $  662,553
 Equity in earnings of unconsolidated joint
  businesses                                                    30,073         16,898         75,689         56,436
 Collaborative agreement revenues                               31,231         18,346         85,792         28,868
 Other revenues                                                 19,715          9,133         51,677         26,828
                                                            ----------     ----------     ----------     ----------
    Total revenues                                             321,549        274,688        943,035        774,685

Expenses:
 Cost of sales                                                 107,861        102,513        316,973        301,343
 Research and development                                       89,921         88,689        265,758        259,649
 Selling, general and administrative                            96,782         85,280        287,841        258,539
 Write-off of purchased in-process technologies                     --        132,535             --        364,951
 Costs related to Ciba transaction                                  --             --             --         49,478
 Restructuring and reorganization costs                             --             --             --         39,055
 Other operating expenses                                        3,193          3,536          8,793          9,323
                                                            ----------     ----------     ----------     ----------
    Total expenses                                             297,757        412,553        879,365      1,282,338
                                                            ----------     ----------     ----------     ----------

Income (loss) from operations                                   23,792      (137,865)         63,670      (507,653)

Other expense, net                                             (6,820)        (2,781)        (5,878)        (6,281)
                                                            ----------     ----------     ----------     ----------

Income (loss) before income taxes                               16,972      (140,646)         57,792      (513,934)

Provision for income taxes                                       5,194          4,461         17,916         16,122
                                                            ----------     ----------     ----------     ----------

Net income (loss)                                            $  11,778   $  (145,107)      $  39,876   $  (530,056)
                                                            ----------     ----------     ----------     ----------
                                                            ----------     ----------     ----------     ----------

Net income (loss) per share                                    $  0.07      $  (0.90)        $  0.22      $  (3.30)
                                                            ----------     ----------     ----------     ----------
                                                            ----------     ----------     ----------     ----------

Weighted average number of shares
 used in computing per share amounts                           175,848        161,716        177,292        160,840
                                                            ----------     ----------     ----------     ----------
                                                            ----------     ----------     ----------     ----------

</TABLE>

   THE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS ARE 
                AN INTEGRAL PART OF THIS STATEMENT.


                                         4

<PAGE>

                                CHIRON CORPORATION
                      CONSOLIDATED STATEMENTS OF CASH FLOWS
                                   (UNAUDITED)
                                 (IN THOUSANDS)
- -------------------------------------------------------------------------------

<TABLE>
<CAPTION>

                                                                     Nine Months Ended
                                                                ----------------------------
                                                                September 30,  September 30,
                                                                     1996         1995
                                                                -------------  -------------
<S>                                                             <C>            <C>

Cash flows from operating activities:
 Net income (loss)                                                $  39,876      $(530,056)
 Adjustments to reconcile net income (loss)
  to net cash provided by (used in) operating activities:
   Depreciation and amortization                                     82,036         67,761
   Gain on sale of interest in affiliated company                   (12,226)            --
   Write-off of purchased in-process technologies                        --        364,951
   Other                                                              7,347         23,768
   Changes to:
    Accounts receivable                                             (57,072)        42,300
    Inventories                                                     (44,073)       (36,720)
    Other current assets                                            (10,588)        (3,401)
    Accounts payable                                                (14,904)        (7,151)
    Accrued compensation and related expenses                        (5,257)        (1,021)
    Taxes payable                                                     6,746         10,961
    Other current liabilities                                        13,073         32,079
    Other noncurrent liabilities                                      5,087        (20,428)
                                                                 ----------       --------
     Net cash provided by (used in) operating activities             10,045        (56,957)
Cash flows from investing activities:
 Purchase of investments in marketable debt securities              (55,008)      (122,177)
 Sale and maturity of investments in marketable debt securities     128,648        278,919
 Capital expenditures                                               (69,514)       (70,559)
 Businesses acquired, net of cash acquired                             (374)      (112,633)
 Proceeds from sale of interest in affiliated company                14,000             --
 Investments in equity securities and affiliates                   (133,700)        (1,103)
 Increase in other assets                                           (32,702)          (547)
                                                                 ----------       --------
     Net cash used in investing activities                         (148,650)       (28,100)
Cash flows from financing activities:
 Net borrowings (payments) under line of credit arrangements        (23,899)        16,769
 Proceeds from issuance of short-term debt                          111,040             --
 Repayment of notes payable and capital leases                       (5,725)        (3,017)
 Proceeds from capital contribution from Ciba                            --         24,845
 Proceeds from issuance of common stock                              36,838         30,630
                                                                 ----------       --------
     Net cash provided by financing activities                      118,254         69,227
                                                                 ----------       --------
     Net decrease in cash and cash equivalents                      (20,351)       (15,830)
Cash and cash equivalents at beginning of the period                 74,318         84,876
                                                                 ----------       --------
Cash and cash equivalents at end of the period                    $  53,967      $  69,046
                                                                 ----------       --------
                                                                 ----------       --------



</TABLE>


  THE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS ARE 
                  AN INTEGRAL PART OF THIS STATEMENT.


                                      5

<PAGE>


                             CHIRON CORPORATION
                  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                       
                              SEPTEMBER 30, 1996


1.   SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

     THE COMPANY

     Chiron Corporation (the "Company" or "Chiron") is a science-driven
     healthcare company that applies biotechnology and other techniques of
     modern biology and chemistry to develop, produce and sell products
     intended to improve the quality of life by diagnosing, preventing and
     treating human disease.  Chiron participates in four global human
     healthcare markets:  diagnostics, therapeutics, pediatric and adult
     vaccines and ophthalmic surgical products.  Chiron also develops or
     acquires new technologies, employing these technologies to discover and
     develop new products for the Company or for its partners.

     Chiron's diagnostic business includes automated immunodiagnostic systems,
     quantitative probe tests and critical blood analyte systems which are
     used by hospitals to diagnose and monitor patients in critical care
     settings. Chiron also provides blood screening tests, used to detect the
     presence of the human immunodeficiency virus ("HIV"), hepatitis virus and
     retroviruses, through its joint business with Ortho Diagnostic Systems,
     Inc. ("Ortho"), a Johnson & Johnson company. Chiron's therapeutics
     business emphasizes oncology and infectious diseases and provides
     products to hospitals and large clinics in the United States and Europe.
     Chiron's vaccine business is based primarily on the sale of pediatric and
     flu vaccines in Italy and other non-U.S., non-European geographic regions
     and to certain international health services, and through the Chiron
     Behring joint venture the sale of vaccines in Germany.  Chiron is also
     involved in the development and marketing of new pediatric and adult
     vaccines.  Through its ophthalmic business, Chiron provides products for
     the surgical correction of vision, as well as intraocular implants that
     deliver drugs to the eye. Chiron's ophthalmic business markets its
     products in the United States, Europe, and other geographic regions.

     BASIS OF PRESENTATION

     The information at September 30, 1996, and for the periods ended
     September 30, 1996 and 1995, is unaudited, but includes all normal
     recurring adjustments which Chiron's management believes to be necessary
     for fair presentation of the periods presented.  The consolidated balance
     sheet amounts at December 31, 1995, have been derived from audited
     financial statements.  Certain previously reported amounts have been
     reclassified to conform with the current period presentation. Interim
     results are not necessarily indicative of results for a full year.  This
     information should be read in conjunction with Chiron's audited
     consolidated financial statements for the year ended December 31, 1995.

     The consolidated financial statements include the accounts of the Company
     and its majority-owned subsidiaries.  All significant intercompany
     accounts and transactions have been eliminated in consolidation.
     Investments in joint ventures, partnerships and interests in which Chiron
     has an equity interest of 50 percent or less are accounted for using the
     equity or cost method, or in accordance with Statement of Financial
     Accounting Standards No. 115, "Accounting for Certain Investments in Debt
     and Equity Securities," as appropriate.  Certain foreign subsidiaries and
     investments in affiliated companies are accounted for on a one-month lag.
     The preparation of financial statements in conformity with generally
     accepted accounting principles requires management to make estimates and
     assumptions that affect the reported amounts of assets and liabilities
     and disclosure of contingent assets and liabilities at the date of the
     financial statements and the reported amounts of revenues and expenses
     during the reporting period.  Actual results could differ materially from
     those estimates.

                                      6


<PAGE>

     FISCAL YEAR

     The fiscal year of the Company is a 52 or 53-week year ending on the
     Sunday nearest the last day in December of each year.  As a result, the
     third quarters of 1996 and 1995 represent the thirteen-week periods ended
     September 29, 1996, and October 1, 1995, respectively.  For presentation
     purposes, dates used in the consolidated financial statements and notes
     refer to the calendar month end.

     INVENTORIES

     Pharmaceutical inventories are stated at the lower of cost or market
     using the average cost method or, in the case of vaccine products, using
     the last-in, first-out ("LIFO") method.  Diagnostic and ophthalmic
     products are valued at cost, using the first-in, first-out ("FIFO")
     method which is less than market value. Inventories consist of the
     following:

                                          SEPTEMBER 30,          DECEMBER 31,
                                              1996                  1995
                                          -------------          ------------
                                                        (IN THOUSANDS)

       Finished goods                       $ 108,502             $   96,327
       Work in progress                        33,989                 28,794
       Raw materials                           44,295                 40,820
                                          -------------          ------------
                                            $ 186,786             $  165,941
                                          -------------          ------------
                                          -------------          ------------

     INCOME TAXES

     Income tax expense for the quarter ended September 30, 1996 is based on
     an estimated annual effective income tax rate.  Income tax expense for
     the quarter ended September 30, 1995 includes a provision for state and
     foreign taxes based on estimated annual effective rates applicable to
     certain of the Company's subsidiaries.

     PER SHARE DATA

     Per share information is based on the weighted average number of common
     and dilutive common equivalent shares outstanding.  Common equivalent
     shares result from the assumed exercise of outstanding options and
     warrants that have a dilutive effect when applying the treasury stock
     method.  Shares assumed to be issued upon conversion of the Company's
     convertible debentures are not included for any of the periods presented
     since their inclusion would be anti-dilutive. Fully diluted per share
     data has not been presented, as the amounts would not differ materially
     from primary per share data.

     At the annual meeting of stockholders in May 1996, stockholders
     approved an amendment to the Company's restated certificate of
     incorporation, increasing the number of authorized common shares from 100
     million to 500 million. Subsequently,  Chiron's Board of Directors
     declared a 4-for-1 stock split effected in the form of a dividend on the
     Company's common stock that was distributed on August 2, 1996, to
     stockholders of record on July 19, 1996.  As a result, the Company
     increased its common stock balance by $1.3 million for the par value of
     the common stock issued to effect the stock split, and correspondingly
     reduced additional paid-in capital.  All warrants, stock options and
     convertible bond conversion rates were adjusted for the effect of the
     split. All references in these financial statements to per share amounts
     have been retroactively restated to reflect the increased number of
     common shares outstanding.

                                      7


<PAGE>

2.   BUSINESS COMBINATIONS

     FIRST QUARTER 1995 ACQUISITIONS

     Effective January 1, 1995, under a series of agreements between Chiron
     and Ciba-Geigy Ltd. and its affiliates ("Ciba"), Chiron acquired all of
     the outstanding common stock of Chiron Diagnostics Corporation ("Chiron
     Diagnostics"), formerly Ciba Corning Diagnostics Corp., and Ciba's
     interests in Chiron Vaccines Company, formerly Chiron Biocine Company,
     and Biocine S.p.A.  On March 31, 1995, Chiron Vision acquired the
     ophthalmic surgical division of IOLAB from Johnson & Johnson. These
     acquisitions were accounted for under the purchase method of accounting.
     As a result of the acquisitions and as required by generally accepted
     accounting principles, during the first quarter of 1995, Chiron
     recognized as an expense the amount allocated to purchased in-process
     technology resulting in a charge against earnings of $230.7 million.
     Costs related to the Ciba transaction totaling $49.5 million were also
     included in the first quarter of 1995, primarily representing employee
     payments and related taxes, and legal and investment advisor fees.

     ACQUISITION OF VIAGENE, INC. ("VIAGENE")

     On September 29, 1995, Chiron acquired all of the outstanding common
     stock of Viagene, not previously owned by the Company, in exchange for
     approximately $35.5 million in cash and 3.7 million shares of Chiron
     common stock.  Additionally, on September 29, 1995, unexercised options
     to purchase Viagene common stock were converted into options to purchase
     approximately 528,000 shares of Chiron common stock.  These shares and
     options have been adjusted for the stock split effected in August 1996.
     Prior to the acquisition, Chiron had an ongoing collaboration with
     Viagene in the area of gene therapy and, pursuant to the collaboration
     arrangement, held an investment in the outstanding voting stock of
     Viagene with a carrying value, net of unrealized gains and a realized
     loss, of approximately $14.1 million as of September 29, 1995.  The
     Viagene acquisition has been accounted for under the purchase method of
     accounting, and accordingly, Viagene's financial results are included in
     Chiron's consolidated operating results from September 29, 1995 forward.

     The following unaudited pro forma information presents the results of
     operations of Chiron and Viagene for the three-month and nine-month
     periods ended September 30, 1995, with pro forma adjustments as if the
     acquisition had been consummated on January 1, 1995.  This pro forma
     information does not purport to be indicative of what would have occurred
     had the acquisition been made as of those dates or of results which may
     occur in the future. The pro forma information does not include the
     write-off of purchased in-process technology of $130.3 million related to
     the acquisition recognized as an expense in the third quarter of 1995.

                                    THREE MONTHS ENDED      NINE MONTHS ENDED
                                    SEPTEMBER 30, 1995      SEPTEMBER 30, 1995
                                    ------------------      ------------------
                                      (IN THOUSANDS, EXCEPT PER SHARE DATA)

 Total revenues                         $  276,930              $  781,643
 Loss before non-recurring 
    charges                                (20,263)               (145,070)
 Loss before non-recurring 
    charges per share                        (0.12)                  (0.88)


     AGREEMENT WITH BEHRINGWERKE AG

     Effective July 1, 1996, Chiron purchased a 49 percent interest in the
     human vaccine business of Behringwerke AG, a subsidiary of Hoechst AG, a
     German company.  The total acquisition price, which was payable in cash
     and subject to adjustment pending the completion of an audited opening
     balance sheet, was $119.0 million and includes costs directly related to
     the acquisition.  This amount has been reflected as a component of
     investments in equity securities and affiliated companies in the
     accompanying September 30, 1996 consolidated balance sheet.  Of the total
     acquisition price, $96.4 million was allocated to various intangible
     assets such as goodwill, trademarks and patents, and is being amortized
     on a straight-line basis

                                      8


<PAGE>

     over lives ranging from 5 to 20 years.

     Under the terms of the agreement, Chiron has an option to purchase the
     remaining 51 percent interest in March 1998, 1999, 2000 or 2001, and
     Behringwerke AG has the option to have Chiron acquire the remaining 51
     percent interest in March 2001.  During the period of mutual ownership,
     Chiron and Behringwerke AG will operate the vaccine business as a joint
     venture, which has been named Chiron Behring.

     During the quarter ended September 30, 1996, Chiron recognized $0.8
     million as its share of the joint venture's results, which includes
     amortization of the aforementioned intangible assets, as equity in
     earnings of unconsolidated joint businesses.  The results of the venture
     are reported on a one-month lag.

3.   RESTRUCTURING AND REORGANIZATION COSTS

     During 1995, Chiron recorded $39.1 million in restructuring and
     reorganization charges, including $16.9 million arising from the
     acquisition and integration of IOLAB, representing the expected costs of
     integrating the acquired business with Chiron's existing business as well
     as write-downs of previously capitalized costs.  Of the total charge of
     $39.1 million, $8.0 million was due to a change in plans to expand the
     Company's Emeryville research and development facilities, $7.7 million was
     related to the idling of the Company's Puerto Rico manufacturing facility
     and $1.0 million was related to a scale-back of manufacturing operations
     at the Company's Amsterdam facility.  The majority of these
     facility-related charges, as well as $3.7 million of other
     facility-related charges, were paid in 1995.  Of the $16.9 million
     recorded as a result of the acquisition of IOLAB, approximately $6.7
     million related to write-downs of previously capitalized facility and
     inventory costs.  The remaining $10.2 million consists of $5.5 million of
     employee termination costs and $4.7 million of lease termination and
     other costs.  The integration process is expected to be substantially
     complete by the end of 1997.

     The current status of the accrued restructuring charges is summarized
     below:

<TABLE>
<CAPTION>
                                                              AMOUNT
                                               AMOUNT OF     UTILIZED       AMOUNT TO
                                                 TOTAL        THROUGH      BE UTILIZED
                                             RESTRUCTURING  SEPTEMBER 30    IN FUTURE
                                                 CHARGE         1996         PERIODS
                                             -------------  -------------  -----------
                                                           (IN THOUSANDS)
<S>                                          <C>             <C>            <C>
Chiron Vision restructuring charges:
   Employee-related costs                      $  5,506     $  (5,506)       $    --
   Facility and lease termination costs           6,242        (3,296)         2,946
   Duplicate and excess inventory                 3,476        (2,564)           912
   Other                                          1,724        (1,041)           683
                                             -------------  -------------  -----------
                                                 16,948       (12,407)         4,541

Puerto Rico manufacturing facility                7,650        (3,670)         3,980
Postponement of Emeryville facility expansion     7,990        (7,990)            --
Amsterdam manufacturing facility                  1,000        (1,000)            --
Other facility-related                            3,718        (3,718)            --
Other                                             1,750        (1,450)           300
                                             -------------  -------------  -----------
                                               $ 39,056     $ (30,235)      $  8,821
                                             -------------  -------------  -----------
                                             -------------  -------------  -----------
</TABLE>

                                      9

<PAGE>


4.   COLLABORATIONS AND JOINT BUSINESS ARRANGEMENTS

     GENERAL

     The Company has entered into a number of collaborative arrangements with
     other pharmaceutical and biotechnology companies for the development and
     marketing of certain technologies and products.  The majority of these
     collaborations are in the development or clinical trial phase.  Chiron
     and its collaborative partners generally contribute certain technologies
     and research efforts to the collaboration.  In addition, Chiron and its
     collaborative partners commit, subject to certain limitations and
     cancellation clauses, to share in the funding of the collaborations'
     ongoing research and clinical trial costs.  Chiron, under certain of the
     arrangements, has purchased equity securities, including common and
     preferred stock and warrants to purchase common and preferred stock, of
     the collaborative partner.

     JAPAN TOBACCO INC. ("JT")

     In March 1996, the Company and JT entered into a technology transfer and
     development agreement whereby the pharmaceutical division of JT acquired
     a non-exclusive, perpetual license to apply certain of Chiron's
     combinatorial chemistry technologies in JT's research and product
     development programs.  Both Chiron and JT will share in certain
     improvements to the technology made by either party, subject to certain
     conditions. The agreement provides an initial technology transfer term of
     two years and may be extended at the option of JT for an additional two
     years. Through September 30, 1996, Chiron received collaborative research
     agreement revenues from JT of $7.6 million, substantially all of which
     was recognized in the first quarter of 1996.

     CIBA AND FOCAL INC. ("FOCAL")

     In April 1996, Chiron, Ciba and Focal entered into an agreement in the
     area of restenosis, the reclosure of arteries following angioplasty.
     Chiron and Ciba will each individually utilize its own cardiovascular
     drugs together with Focal's drug delivery technology to develop products
     designed to prevent restenosis.  Under the terms of the agreement, Chiron
     and Ciba will receive exclusive worldwide rights to Focal's technology in
     selected restenosis fields for their respective drug compounds entered
     into the research program.  Chiron and Ciba will be individually
     responsible for developing and marketing the resulting products, and
     Focal will retain manufacturing rights for the final products.  Chiron
     and Ciba will jointly provide funding for certain preclinical studies,
     after which each company will fund development for its own products. Each
     company will also be individually responsible to make milestone payments
     to Focal for its products developed, totaling $10.0 million per product.
     Through September 30, 1996, Chiron paid Focal $0.3 million for its share
     of costs which was recorded as research and development expense.

     RIBOZYME PHARMACEUTICALS INC. ("RPI")

     In May 1996, Chiron and RPI entered into a collaboration to use RPI's
     ribozyme technology to determine the function of a number of genetic
     sequences.  Chiron will select a certain number of gene sequences and RPI
     will synthesize ribozymes that will selectively inhibit the action of the
     target sequences in Chiron's assays.  Chiron will have the option to
     develop, and, in certain circumstances, manufacture ribozymes or other
     products found to be important in disease pathology.  Under the terms of
     the agreement, Chiron will pay RPI for the ribozymes used in the research
     and make milestone payments depending upon the number of products
     successfully developed.  Chiron also agreed to pay RPI royalties from the
     sale of commercialized products.  The royalty payments will be reduced by
     up to 50 percent of the milestone payments made as it relates to specific
     products.  Through September 30, 1996, no costs have been incurred.

                                      10


<PAGE>

     Under the terms of a separate agreement dated February 29, 1996, RPI
     committed to provide funding for certain research projects.  During the
     quarter ended September 30, 1996, Chiron recognized $1.8 million of
     collaborative agreement revenues pursuant to this agreement.

     GENERAL INJECTABLES & VACCINES, INC. ("GIV")
     
     In September 1996, Chiron reached an agreement with Biological and
     Popular Culture, Inc. ("BPC"), a newly organized holding company for GIV
     and affiliated companies, pursuant to which GIV and its affiliates agreed
     to perform certain distribution and promotional services for Chiron's
     vaccine products in the U.S.  The initial term of the service agreement
     is five years, with potential one year extensions thereafter.
     
     In connection with the agreement, Chiron invested $30.0 million in BPC,
     of which $13.8 million consisted of BPC voting preferred stock which is
     convertible at Chiron's option into 30 percent of the outstanding common 
     stock of BPC. Alternatively, Chiron, at its option, may require BPC to re-
     deem the preferred stock at par plus accrued dividends at a future date. Of
     the preferred stock investment, a significant amount represents excess
     purchase price and will be amortized over the term of the five-year
     initial service agreement.  The remainder of the $30.0 million investment
     consisted primarily of two interest-bearing loans to BPC and its
     subsidiaries with various maturities.  Chiron agreed to make additional
     capital contributions in the event BPC exceeds certain earnings
     requirements and which BPC agreed to use to repay one of the loans.
     
     Chiron will report its share of BPC's results, including amortization
     of the aforementioned excess purchase price, as equity in earnings of
     unconsolidated joint businesses.

     BEN VENUE LABORATORIES, INC. ("BEN VENUE")

     Effective May 1, 1996, Chiron sold its 50 percent interest in a generic
     oncology business to Ben Venue, Chiron's joint venture partner, for $14.0
     million in cash, resulting in a $12.2 million gain which has been
     included in other expense, net in the accompanying consolidated
     statements of operations.

5.   FINANCIAL INSTRUMENTS

     FOREIGN CURRENCY CONTRACTS

     To reduce its exposure to foreign currency risk, the Company enters into
     forward currency contracts ("forwards") and, starting in 1996, purchases
     average rate put options ("options").  Forward currency contracts are
     used to hedge material foreign currency denominated receivables and
     payables, while the options are used to hedge anticipated transactions.
     The Company does not use these financial instruments for trading or
     speculative purposes.

     The Company has purchased, and may in the future purchase options to
     reduce the exchange rate impact of a strengthening U.S. dollar on the
     underlying hedged amounts.  The Company's exposure is limited to the
     amount paid for the options.  The cost of the options, which is recorded
     in other current assets, is deferred and amortized over the relevant term
     of the period hedged.  Any corresponding gains are reported in income at
     the conclusion of the period hedged.

     At September 30, 1996, the notional amount of the forwards and options
     totaled $69.9 million and $19.1 million, respectively.  The options were
     denominated in the following currencies: Japanese yen, French francs,
     Australian dollars, Canadian dollars, Belgian francs and Spanish pesetas.
     All option contracts expire through December 1996.  The fair value of the
     options at September 30, 1996, based upon dealer quotes, totaled
     approximately $0.3 million.

                                      11


<PAGE>


     CROSS CURRENCY INTEREST RATE SWAPS

     The Company selectively enters into cross currency interest rate swaps
     ("swaps") through major financial institutions to modify the interest
     and/or currency characteristics of specific outstanding debt obligations.
     Each swap agreement corresponds to all or a portion of the principal
     balance and term of a specific debt obligation. These swap agreements
     involve the exchange of interest payments denominated in different
     currencies, based upon the terms described in the swap agreements, with
     an exchange of the underlying notional principal amounts upon maturity.
     The net difference between the interest amounts paid and received is
     recognized as an adjustment of interest expense.  The related interest
     amount payable or receivable from the major financial institutions is
     included in other current liabilities or assets.

     In May 1996, the Company entered into a swap agreement that matures in
     June 1997 with a notional amount of $24.9 million.  The Company
     effectively converted debt denominated in U.S. dollars to Japanese yen.
     The agreement provides for the Company to make quarterly interest
     payments starting June 30, 1996, based on a variable rate tied to
     three-month Japanese LIBOR (0.56% at September 30, 1996) while receiving
     interest based on a variable rate tied to three-month U.S. dollar LIBOR
     (5.6% at September 30, 1996).

     In July 1996, the Company also entered into swap agreements that mature
     in July 2001 with an aggregate notional amount of $112.6 million.  The
     Company effectively converted debt denominated in U.S. dollars to German
     marks. The agreements provide for the Company to make quarterly interest
     payments based upon a fixed German mark rate of 6.2% while receiving
     interest based on a variable rate tied to three-month U.S. dollar LIBOR.

6.   LINE OF CREDIT ARRANGEMENTS

     During 1996, the Company expanded its short-term borrowing capacity by
     entering into two separate one-year revolving, unsecured credit
     agreements with major financial institutions for borrowing capabilities
     up to $50.0 million and $100.0 million, respectively.  These facilities
     bring the total committed, unsecured short-term revolving credit
     facilities available to the Company in the U.S. to $200.0 million.  The
     credit facilities in the U.S. are guaranteed by Ciba and provide for
     various borrowing rate options, as defined in the agreements.  As of
     September 30, 1996, $100.0 million was outstanding under these facilities
     with interest rates tied to U.S. dollar LIBOR (5.7% at September 30,
     1996).

7.   OPERATING LEASE

     In June 1996, the Company entered into a seven-year operating lease
     agreement with a group of financial institutions to rent a research and
     development facility to be constructed in Emeryville, California. Under
     the terms of the lease agreement, the financial institutions have
     committed $195.0 million toward the total construction cost of the
     project. No lease payments are required during the construction period
     which is expected to last less than three years.  Thereafter, rent
     amounts will be due quarterly, based upon the total construction costs
     incurred.

     Under the lease arrangement, which has been guaranteed by Ciba through
     December 31, 1999, the Company has the option to purchase the constructed
     properties.  Alternatively, Chiron can cause the property to be sold to a
     third party.  The Company is also contingently liable under residual
     value guarantees in the event of market value declines.

8.   CONTINGENCIES
     
     ABBOTT LABORATORIES.  On December 13, 1993, Chiron filed a patent
     infringement action against Abbott Laboratories ("Abbott") in the United
     States District Court for the Northern District of California, alleging
     infringement of Chiron's U.S. Patent No. 5,156,949 ("the '949 patent").
     The patent claims the use of recombinant envelope antigens in immunoassays
     for HIV antibodies. On April 1, 1996, Chiron and Ortho,


                                      12


<PAGE>

     Chiron's exclusive licensee under the '949 patent, entered into a 
     settlement agreement with Abbott under which Abbott will be granted a 
     royalty-bearing, non-exclusive license under the '949 patent and 
     foreign counterparts thereof.  The litigation was dismissed on August 
     31, 1996, and in the third quarter of 1996 Chiron received $6.9 million 
     of royalties related to prior period sales of HIV immunodiagnostics 
     tests. This amount has been reflected in equity in earnings of 
     unconsolidated joint businesses in the accompanying consolidated 
     statements of operations.  Under the terms of the settlement agreement, 
     the Chiron-Ortho joint business will also receive an ongoing royalty 
     from Abbott based on the sale of products incorporating the patents.
     
     On September 12, 1995, the United States Patent & Trademark Office
     ("PTO") declared an interference between the '949 patent and an
     application owned by the U.S. Government and Centocor, Inc. ("Centocor").
     Chiron is the junior party.  In the above described litigation with
     Abbott, the District Court granted Chiron's request for summary judgment
     that the U.S. Government/Centocor application in the subject
     interference, which is senior to Chiron's, neither enabled the claimed
     invention nor disclosed the best mode of practicing the invention.  If 
     the PTO makes a similar ruling on either enablement or best mode, Chiron 
     could then become the senior party. It is not known when or on what 
     basis the PTO will resolve the subject interference.
     
     On April 26, 1994, Abbott filed suit against Chiron in the United States
     District Court for the Northern District of Illinois alleging that the
     Company's bDNA probe assays infringed three patents licensed or acquired
     by Abbott from third parties.  On April 1, 1996, Chiron and Abbott
     entered into a settlement agreement under which Chiron will be granted a
     royalty-bearing, non-exclusive license under the three patents in suit
     and the foreign counterparts thereof.  The litigation was dismissed on
     August 20, 1996.
     
     BIOANALYSIS/GEN-PROBE.  On March 22, 1996, Chiron Diagnostics filed suit
     in the United States District Court for the Southern District of
     California against Bioanalysis Limited, Gen-Probe Incorporated and the
     University of Wales College of Medicine alleging, among other things,
     patent infringement, intentional interference with contractual rights and
     breach of contract. Chiron Diagnostics' claims arose under its 1984
     license from Bioanalysis of chemiluminescent technology used by Chiron
     Diagnostics in its ACS-TM- and Magic-Registered Trademark- Lite 
     diagnostic test kits. After Chiron Diagnostics filed suit, Bioanalysis 
     made certain demands and counterclaims.  On July 1, 1996, the parties 
     entered into a settlement agreement.  Under the terms of the 
     settlement, among other things, Chiron Diagnostics and Bioanalysis have 
     entered into an amended and restated license, Chiron Diagnostics and 
     Gen-Probe Incorporated agreed to certain cross-licenses, and each of 
     the actions brought among the parties has been dismissed.
     
     DANIEL W. BRADLEY.  On December 20, 1994, Dr. Daniel W. Bradley, formerly
     with the U.S. Centers for Disease Control (the "CDC"), brought suit 
     in the United States District Court for the Northern District of
     California against Chiron, Ortho, certain employees of Chiron, and the
     United States government. Subsequently, Bradley dismissed the United
     States as a defendant.  Bradley, who collaborated with Chiron scientists
     on the research that led to the discovery of HCV, alleged he has been
     wrongly excluded as an inventor of HCV.  He requested various forms of
     relief, including declarations that he was an inventor of Chiron's
     patents related to HCV and that these patents were unenforceable. Bradley
     further sought monetary damages and a constructive trust on all past and
     future profits, as well as penalties under federal and state Racketeering
     and Corrupt Organization (RICO) statutes. On July 15, 1996, the Court
     dismissed Bradley's second amended complaint with prejudice and without
     further leave to amend. Bradley has appealed the District Court's 
     decision to the United States Court of Appeals for the Federal Circuit.  
     The Company intends to oppose that appeal.
     
     EVANS.  Biocine S.p.A. ("Biocine") filed an action against Evans Medical
     Limited (a division of Medeva plc) ("Evans") in the Tribunal of Milan on
     October 23, 1995, seeking a declaration of invalidity of Evans' Italian 
     counterpart to its European Patent No. 0 162 639 ("the '639 patent"), 
     allegedly relating to the p69 antigen of BORDATELLA PERTUSSIS. Biocine 
     later filed a claim against Evans with the Milan court seeking a 
     declaration of noninfringement with respect to Biocine's Acelluvax-TM- 
     and Acelluvax-TM- DTP vaccines. Evans has responded that Biocine's 
     vaccines infringe the '639 patent. Also, in February 1996, Chiron and
     Chiron B.V. filed an action seeking a declaration of invalidity and non-
     infringement with respect to Evans' Dutch equivalent to the '639 patent

                                      13
<PAGE>

     in the District Court of The Hague in The Netherlands. On April 4, 1996, 
     a similar action was filed by Chiron against Evans' U.K. equivalent to 
     the '639 patent in the High Court of Justice, Chancery Division, Patents 
     Court of the U.K. SmithKline Beecham Biologicals S.A. ("SKBB"), Evans' 
     exclusive licensee, and Medeva plc were also named as defendants. On 
     April 4, 1996, Evans filed suit against Chiron in the United States 
     District Court for the Eastern District of Texas. The complaint, which was
     not served on Chiron until July 1996, alleges that Chiron infringes the 
     U.S. Patent Nos. 5,237,052 and 5,438,120 which are counterparts of the 
     '639 patent. Evans seeks a permanent injunction, plus damages. Chiron 
     believes that the Biocine vaccines do not infringe any valid claim of the 
     '639 patent or its U.S. counterparts. Biocine previously had opposed 
     issuance of the '639 patent before the European Patent Office 
     ("EPO") and, along with other parties, has appealed the EPO opposition 
     decision which maintained the patent in amended form.

     INTERNATIONAL MUREX TECHNOLOGIES CORPORATION. Chiron, Ortho, and certain 
     Ortho affiliates (the "Chiron/Ortho parties") have been involved in a 
     series of legal actions against subsidiaries of International Murex 
     Technologies Corporation ("IMTC") related to infringement of Chiron's HCV 
     patents in HCV immunodiagnostics. The first such action was filed on March 
     2, 1992 in the High Court for England and Wales. Subsequent infringement 
     suits were filed in Germany, The Netherlands, Italy, Belgium and Australia.
     Chiron sought damages and injunctions against future infringement in these
     actions. On June 11, 1996, Murex Diagnostics Australia, Pty. Limited 
     ("MDAUS") filed an action against Chiron and Ortho in the Federal Court of
     Australia, New South Wales District Registry, General Division, alleging 
     violation of the Australian 1974 Trade Practices Act and seeking an order 
     which would restrain Chiron and Ortho from engaging in allegedly anti-
     competitive activities in connection with their HCV tests. On August 27, 
     1996, the Chiron/Ortho parties and IMTC entered into a settlement 
     agreement the specific terms of which are confidential. Under the terms of
     the settlement agreement, all of the litigation referenced above, with 
     the exception of litigation with IMTC's subsidiary, Murex Diagnostics, 
     Ltd. ("MD") will be dismissed. On February 22, 1996, MD made it known that
     it had changed its name to Specialist Diagnostics Ltd. ("SDL"), and filed 
     a petition for voluntary liquidation. The Chiron/Ortho parties and the 
     trustees for SDL entered into a settlement agreement in September 1996. 
     It is expected that the U.K. bankruptcy court will approve the settlement 
     and that the subject litigation will be dismissed.

     On March 5, 1996, IMTC filed a complaint against Chiron, Johnson & 
     Johnson ("J&J"), Institut Pasteur and Abbott Laboratories with 
     the European Commission ("EC"), alleging violations of Articles 85 
     and 86 of the EC Treaty and Articles 53 and 54 of the European 
     Economic Area Agreement concerning licensing practices under 
     Chiron's U.K. Patent No. 2,212,511 ("the '511 patent") and 
     European Patent No. 0 318 216 ("the '216 patent"), a counterpart of 
     the '511 patent. The EC complaint charges that Chiron and J&J have 
     entered into license agreements with competitors which constitute
     market sharing and price fixing in the HCV and other blood testing fields,
     thus abusing an allegedly dominant position in the HCV market. IMTC claims
     that Chiron's HCV patents constitute an "essential facility" which must be
     "freely licensed on reasonable commercial terms." The EC complaint seeks, 
     among other things, interim measures in the form of a compulsory license 
     from Chiron to IMTC applicable in all European Union member states for the
     manufacture of HCV antigen and nucleic acids for immunodiagnostic reasons. 
     The EC has posed certain questions to the parties and Chiron has responded.

     On April 11, 1996, the Opposition Division of the EPO upheld the
     '216 patent in amended form over the oppositions of MD/SDL, United 
     Biomedical, Inc., F. Hoffmann-LaRoche & Co. AG., Behringwerke AG and 
     the Research Foundation for Microbial Diseases of Osaka University. 
     The Opposition Division's decision is subject to appeal.

                                       14
<PAGE>

     NATIONAL TRANSPORTATION SAFETY BOARD ("NTSB"). On September 5, 1996, a 
     DC-10 aircraft operated by Federal Express Corporation, and the majority 
     of its cargo, was destroyed by fire.  The NTSB, an agency of the federal 
     government, is investigating all of the circumstances surrounding the 
     incident.  One area of the NTSB investigation concerns possible linkage 
     between the fire and certain Chiron laboratory equipment which was 
     shipped in a Federal Express container aboard the aircraft.  Chiron 
     elected to become a party to that investigation and is providing 
     information and assistance to the NTSB. The NTSB has not yet reached any 
     conclusions concerning the cause of the fire.
  
     LUIS RUIZ AND SERGIO LENCHIG.  On October 1, 1996, Luis Ruiz and Sergio  
     Lenchig, owners of U.S. Patent No. 5,133,726 and certain other 
     proprietary rights related to corneal shaping, filed a lawsuit against 
     Chiron Vision in the United States District Court for the Eastern 
     District of Virginia.  The lawsuit alleges that Chiron Vision breached 
     the license agreement among Ruiz, Lenchig, and Chiron for such 
     technology.  Plaintiffs seek declaratory relief and damages according to 
     proof.  The Company has not yet filed its response.         

     SICOR.  As of April 10, 1996, Chiron entered into a settlement 
     agreement which resulted in dismissal of a 1991 lawsuit filed 
     in the United States District Court for the Northern District 
     of California against Cetus Oncology Corporation ("Cetus"), 
     Ben Venue Laboratories, Inc., Cetus Ben Venue Therapeutics ("CBVT")
     and Erbamont, Inc. and its affiliates by Alco Chemicals, Ltd. ("Alco")
     and Sicor, S.p.A. ("Sicor"). The Sicor complaint alleged breach of a CBVT
     contract to purchase bulk doxorubicin from Sicor, as well as antitrust
     violations and interference with contract and prospective advantage, and
     sought unspecified damages. Cetus denied any entitlement to recovery in
     this lawsuit and had filed counterclaims.  In February 1995, Sicor and
     Alco filed a further action in the United States District Court for the
     Northern  District of California and an arbitration against CBVT for
     amounts  allegedly owed by CBVT to Sicor and Alco for the supply of 
     doxorubicin, plus interest and attorneys' fees.  Under the April 10, 
     1996 settlement agreement, each of the actions brought among the parties
     was dismissed with prejudice.
     
     SMITHKLINE BEECHAM BIOLOGICALS S.A.  Chiron owns issued 
     European Patent No. 0 120 551 ("the '551 patent") which relates to 
     yeast expression vectors containing foreign gene sequences including, 
     for example, hepatitis B virus ("HBV") surface antigen, and expression 
     methods thereof.  Chiron also owns European Patent No. 0 460 716 ("the 
     '716 patent") which contains related claims.  Chiron believes that 
     SKBB's  Engerix-B-Registered Trademark- vaccine against HBV infringes 
     the '551 patent and the '716 patent.  In April 1996, SKBB filed suit 
     against Chiron in the Tribunal of First Instance of Brussels seeking a 
     declaration that the '551 and '716 patents are:  (1) null and void in 
     Belgium; and (2) not infringed by SKBB in a variety of European 
     countries.  SKBB also filed an application for preliminary relief 
     which, if granted, would suspend the effects of the '551 and '716 
     patents and would allow SKBB to continue production and 
     commercialization of Engerix-B-Registered Trademark- in all designated 
     countries until a decision on validity and infringement is rendered.
     A substantive hearing on SKBB's preliminary relief application is expected
     to be held in the first quarter of 1997.

     STAAR SURGICAL COMPANY ("STAAR").  On May 7, 1996, Chiron Vision filed a
     lawsuit in the Superior Court of the State of California for the County 
     of Los Angeles against Staar for specific performance, indemnity, 
     breach of contract, an accounting and declaratory relief.  The 
     lawsuit asserts, among other things, that Staar failed to honor 
     certain indemnity obligations related to Staar's rights in certain 
     foldable lens technology licensed to Chiron Vision, failed to
     extend to Chiron Vision most favored rates and/or terms in connection
     with its license from Staar of certain foldable lens technology, which
     includes US Patent No. 4,573,998, and failed to transfer to Chiron Vision
     rights to certain technology as contractually obligated.  Chiron Vision
     seeks damages, declaratory and other relief. Staar has denied Chiron
     Vision's allegations and filed a cross-complaint against Chiron Vision
     alleging breach of contract and other claims and seeking declaratory
     relief and damages according to proof.

                                      15


<PAGE>

     STOCKHOLDER LITIGATION.  In November 1994, Chiron, its directors, and
     certain of its officers were sued in three essentially identical lawsuits
     filed as class actions on behalf of Chiron stockholders, alleging that
     the directors had violated their fiduciary duty by failing to maximize
     stockholder value in connection with the series of transactions effected
     with Ciba-Geigy, Ltd. which were announced on November 20, 1994. Two of
     the actions filed respectively on November 14, 1994 and November 22, 1994
     (HANNA V. CHIRON CORP., ET AL., C.A. No. 13874, and DEZUBE V. CHIRON
     CORPORATION ET AL., C.A. 13896) were filed in the Court of Chancery of
     the State of Delaware in and for New Castle County.  These complaints
     sought injunctive relief, rescission and attorneys' fees.  Plaintiff in
     the HANNA action additionally sought damages in an unspecified amount.
     Plaintiff in the DEZUBE action additionally sought an accounting.  The
     complaints were answered by all defendants, who denied the material
     allegations of the complaints. The third action was filed in the Superior
     Court of California, Alameda County, Northern Division, on December 1,
     1994 (PERERA ET AL., V. CHIRON CORPORATION ET AL., C.A. No. 744522-2).
     Plaintiffs there sought injunctive and declaratory relief, an
     accounting, costs and disbursements, including attorneys' and experts'
     fees, and other relief.
     
     On October 17, 1995, the PERERA plaintiffs commenced a new action (the
     "Federal Action") in the United States District Court for the Northern
     District of California, against the same defendants and Ciba-Geigy, Ltd.,
     Ciba-Geigy's Chairman Alex Krauer, Ciba-Geigy Corporation, and Ciba
     Biotech Partnership, Inc. (collectively, the "Ciba Defendants").  The
     Federal Action asserts both state and federal claims, including a claim
     under Sections 10(b), 14(d) and 14(e) of the Securities Exchange Act of
     1934, and seeks damages and injunctive relief.  On October 23, 1995, in
     light of the filing of the Federal Action, the PERERA action was
     dismissed by stipulation of the parties.
     
     Plaintiffs and all of the defendants other than the Ciba Defendants
     entered into an agreement to settle the Federal Action on a class-wide
     basis, subject to approval by the Court. Under the terms of that
     settlement agreement, Chiron has paid attorneys fees and expenses to
     plaintiffs' counsel and agreed to redeem or otherwise render ineffective
     the stockholder rights plan created under that certain Rights Agreement
     dated as of August 25, 1994, as amended.  Chiron has no other obligations
     under the settlement agreement.  The HANNA and DEZUBE actions are to be
     dismissed as moot following approval of the settlement and dismissal of
     the Federal Action.  The settlement received final approval of the court
     on May 21, 1996.
     
     SUMMIT TECHNOLOGY, INC.  On June 11, 1996, the German Federal Patent
     Court dismissed an action filed by Chiron Technolas, a subsidiary of
     Chiron Vision, which sought to invalidate the German counterpart of a
     European patent held by an affiliate of Summit Technology, Inc., a
     manufacturer of ophthalmic lasers.  The Company has decided not to
     appeal this decision.  Summit's German patent is also the subject of a
     separate infringement action filed on September 24, 1994 by Summit
     against Chiron Technolas and another subsidiary of Chiron Vision, Chiron
     Adatomed, in the German Regional Court.  The Regional Court granted
     judgment for Summit in August 1995, including an injunction, and awarded
     damages in an amount to be determined.  The Company's appeal of the
     judgment is pending.
     
     UNITED BIOMEDICAL, INC.  On May 14, 1992, the Chiron/Ortho parties brought
     an infringement action against United Biomedical, Inc. ("UBI") and certain
     companies of the Akzo Nobel Group ("Organon") for infringement of the '511
     patent directed to HCV immunodiagnostics.  On May 4, 1994, Chiron 
     instituted summary legal proceedings against UBI and Organon in the 
     District Court of The Hague, The Netherlands, alleging infringement of the
     '216 patent as a result of the defendants' manufacture and sale of HCV 
     immunoassay kits. UBI supplied and Organon marketed HCV immunoassay test 
     kits throughout Europe.  Both the U.K. and Dutch courts granted Chiron 
     injunctions against future infringement by UBI and Organon, and the U.K. 
     court ordered Organon and UBI to pay damages.  The Chiron/Ortho parties 
     and Organon settled all HCV litigation pending between them on October 9, 
     1995, and the Chiron/Ortho parties were compensated for past infringement.
     The Chiron/Ortho parties and UBI entered into a settlement agreement 
     effective May 1, 1996 the terms of which are confidential and under 
     which the U.K. and Dutch litigation has been dismissed.

                                      16
<PAGE>


     OTHER MATTERS. The Company is party to other matters of litigation,
     certain of which are described in Item 3, Legal Proceedings, on page 10
     of the Company's report on Form 10-K for the period ended December 31,
     1995, and as to which there have been no material changes since such 
     Form 10-K was filed.

                                      17


<PAGE>

                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
                                       
OVERVIEW

     The discussion below contains forward-looking statements that involve
risks and uncertainties relating to the future financial performance of Chiron
Corporation (the "Company" or "Chiron"), and actual events or results may
differ materially.  In evaluating such statements, stockholders and investors
should specifically consider the various factors identified below and under
the caption "Factors That May Affect Future Operating Results" which could
cause actual results to differ materially from those indicated by such
forward-looking statements.

     Chiron is a science-driven healthcare company that applies biotechnology
and other techniques of modern biology and chemistry to develop, produce and
sell products intended to improve the quality of life by diagnosing,
preventing and treating human disease.  Chiron participates in four human
healthcare markets:  diagnostics, including blood screening tests, automated
immunodiagnostic systems, critical blood analyte systems and new quantitative
probe tests; therapeutics, with an emphasis on oncology, serious infectious
diseases and critical care diseases; adult and pediatric vaccines; and
ophthalmic surgical products, including instruments and devices used for the
surgical correction of vision and intraocular implants to deliver drugs to
the eye. Chiron also develops or acquires new technologies, employing these
technologies to discover and develop new products for the Company or for its
partners.

RESULTS OF OPERATIONS

REVENUES

     The Company's revenues are derived from a variety of sources, including
product sales, joint business arrangements, collaborative agreements and
product royalty agreements.  Product sales, Chiron's largest revenue category,
consists of the following product lines for the three-month and nine-month
periods ended September 30:

<TABLE>
<CAPTION>
                                              THREE MONTHS          NINE MONTHS
                                           ENDED SEPTEMBER 30,   ENDED SEPTEMBER 30,
                                           -------------------  --------------------
                                              1996      1995      1996        1995
                                           ---------  --------  --------    --------
                                                        (IN THOUSANDS)
<S>                                        <C>        <C>       <C>         <C>
    Diagnostic products                     $134,816  $131,194  $412,300    $396,461
    Ophthalmic products                       49,911    45,884   154,365     122,640
    Vaccine products                          21,374    18,217    61,680      53,652
    Betaseron-Registered Trademark- sales     16,807    18,490    49,948      42,706
    Oncology products                         16,595    15,826    48,415      43,761
    Other products                             1,027       700     3,169       3,333
                                           ---------  --------  --------    --------
                                            $240,530  $230,311  $729,877    $662,553
                                           ---------  --------  --------    --------
                                           ---------  --------  --------    --------
</TABLE>


     As Chiron continues to expand its presence in international markets,
particularly European markets, seasonal fluctuations in product sales and the
related gross profit amounts have become more significant. For this reason,
revenues and gross profit amounts from certain product lines are generally
higher in the first half and fourth quarter of the year.  As a result,
Chiron's results in any one quarter are not necessarily indicative of results
to be expected for a full year.

     Diagnostic product sales include direct sales and sales-type leases of 
fully-automated, random-access immunodiagnostic 
(ACS:180-Registered Trademark-, automated chemiluminescence system) testing 
systems and reagents for these systems, as well as sales of critical blood 
analyte systems, clinical chemistry products and manual immunodiagnostic 
systems.  Sales of diagnostic products increased in both the third quarter 
and first nine months of 1996 over the comparable periods in 1995, primarily 
due to increased sales of branched DNA probe tests for human immunodeficiency 
virus ("HIV") and immunodiagnostic products. The growth in immunodiagnostic 
product sales

                                      18

<PAGE>

resulted from continued penetration of the instruments market and increased 
sales volume of reagents resulting from increased system placements and an 
expanded menu of tests on the ACS:180-Registered Trademark- system, partially 
offset by reduced sales of manual immunodiagnostics.

     Sales of ophthalmic products increased for both the third quarter of 
1996 and on a year-to-date basis as compared to 1995.  The sales growth in 
the third quarter of 1996 was primarily due to sales of the Company's new 
Vitrasert-TM- Implant (Cytovene-Registered Trademark-; Roche Laboratories) 
product, the first drug delivery system to provide local, sustained therapy 
for the eye.  Chiron received approval from the U.S. Food and Drug 
Administration ("FDA") during the first quarter of 1996 to market the 
product.  As a result, the Company recorded $3.3 million and $9.1 million of 
Vitrasert-TM- Implant sales during the third quarter and first nine months of 
1996, respectively.  The sales growth during the nine months ended September 
30, 1996 was also due to increased sales of viscoelastic products and sales 
of foldable intraocular lenses as a result of the March 1995 acquisition of 
the surgical product division of IOLAB from Johnson & Johnson and the 
continuing evolution in the marketplace favoring foldable lens 
technology-based products.

     Vaccine product sales consist of sales of pediatric and adult vaccines 
primarily in Italy and to international public health organizations by 
Chiron's Biocine S.p.A. subsidiary ("Chiron Biocine").  Chiron Biocine's 
vaccine products include Acelluvax-Registered Trademark-, a recombinant 
acellular pertussis vaccine; Agrippal-Registered Trademark-, a flu vaccine; 
and Polioral-TM-, an oral polio vaccine.  Vaccine product sales increased for 
both the third quarter of 1996 and on a year-to-date basis as compared to 
1995 due to Chiron Biocine's expansion into new export markets for its polio 
vaccine and its combined measles-mumps-rubella vaccine.  In addition, in 
September 1996 Chiron Biocine submitted a product license application to the 
FDA, seeking approval to market its recombinant acellular pertussis vaccine, 
combined with diphtheria and tetanus ("DTaP"), for infants and children in 
the U.S., under the tradename Pertugen-TM-.

     Under the terms of a development and supply agreement with Schering AG, 
Germany ("Schering"), and its U.S. affiliate, Berlex Laboratories, Inc. 
("Berlex"), Chiron manufactures Betaseron-Registered Trademark- (interferon 
beta-1b) for Berlex. Under the terms of the agreement, Chiron earns an 
initial partial payment for Betaseron-Registered Trademark- upon shipment to 
Berlex and a subsequent secondary payment upon Berlex's final net sales of 
the product to customers.  Betaseron-Registered Trademark- product sales 
during the third quarter of 1996 are comprised primarily of initial and 
secondary revenues and revenues for Betaseron-Registered Trademark- 
distributed by Schering for use in an early access program for European 
patients prior to commercial approval in Europe.  Betaseron-Registered 
Trademark- product sales during the third quarter of 1995 relate primarily to 
initial payments for shipments of Betaseron-Registered Trademark- product to 
Berlex. On a year-to-date basis, Betaseron-Registered Trademark- product 
revenues increased in 1996 compared to 1995 primarily due to secondary 
revenues arising from net sales by Berlex, and European revenues arising from 
product distributed by Schering for use in an early access program for 
European patients.  Chiron expects to continue shipments to Berlex during the 
fourth quarter of 1996 and, accordingly, expects to earn initial and 
secondary revenues from sales to Berlex.  Chiron also expects to earn 
revenues from shipments to Schering for sales into non-U.S. markets in the 
fourth quarter of 1996.

     Future levels of Chiron's Betaseron-Registered Trademark- shipments will 
depend upon the rate at which new patients are enrolled from existing and 
future markets, the extent to which patients, once enrolled, remain compliant 
with the prescribed treatment regimen and continue to regularly receive 
Betaseron-Registered Trademark-, and the impact of competing products, 
including other beta interferon products that were approved for sale in the 
U.S. during 1996.  In addition, based upon the level of inventories carried 
by Berlex, the timing of future shipments to Berlex and the related revenue 
may vary by quarter.

     Sales of oncology products, principally Proleukin-Registered 
Trademark-(aldesleukin, interleukin-2), increased during the three-month and 
nine-month periods ended September 30, 1996, over the same periods in 1995, 
primarily due to increased unit sales.  Average worldwide selling prices 
remained roughly constant between the third quarters of 1996 and 1995 and for 
the first nine months of 1996 compared to 1995.

     The Company markets many of its commercial products internationally.  As
a result, product revenues in almost all product lines are affected by
fluctuating foreign currency exchange rates. Foreign product sales were $132.6
million and $407.4 million for the three-month and nine-month periods ended
September 30, 1996, respectively, versus $125.6 million and $373.0 million for
the comparable periods in 1995, respectively.  International

                                      19


<PAGE>

sales of diagnostic, vaccine and ophthalmic products accounted for the 
majority of the increase in foreign product sales between periods. For the 
three-month and nine-month periods ended September 30, 1996, approximately 56 
percent of Chiron's product sales were denominated in foreign currencies.  
The net effect of changing foreign currency exchange rates did not 
significantly impact product sales when compared with the quarterly and 
year-to-date periods in 1995.  Changing currency exchange rates have had, and 
will continue to have, an impact on Chiron's results.  The Company's other 
revenues, discussed below, are largely denominated in U.S. dollars but are 
impacted by the Company's joint partners' and collaborators' non-U.S. 
operations.

     Joint business revenues consist substantially of Chiron's one-half 
interest in the pretax operating earnings of its joint diagnostic business 
with Ortho Diagnostic Systems, Inc. ("Ortho").  The joint business receives a 
royalty from Abbott Laboratories ("Abbott") for Abbott's sales of hepatitis C 
virus ("HCV") tests which use the Chiron technology and which compete 
directly with tests marketed by Ortho.  Results from the joint business are 
recorded by Chiron on a one-month lag based upon estimates supplied by Ortho 
and are subject to a final annual accounting during the first quarter of the 
subsequent year.  For the third quarter of 1996, Chiron's share of the pretax 
earnings increased to $29.9 million from $15.6 million for the comparable 
quarter in 1995.  In 1996, the joint business recorded increased sales from 
the introduction of a new HIV antigen test as well as increased profits from 
sales growth to Ortho's overseas affiliates.  The increase in profits was 
offset by increased sales and marketing costs associated with the 
introduction of the new HIV antigen test and by sales of certain lower margin 
products. Also included in Chiron's share of the operating results of the 
joint business during the third quarter of 1996 are $6.9 million in royalties 
resulting from a settlement with Abbott related to prior period sales of HIV 
immunodiagnostic tests. Under the terms of the settlement agreement, the 
joint business will receive an ongoing royalty from Abbott based on the sale 
of products incorporating technology covered by certain Chiron HIV patents.

     For the nine-month period ended September 30, 1996, Chiron's share of the
pretax earnings of the joint business with Ortho increased by $18.4 million as
compared to 1995, due to the increasing volume of HCV and HIV tests sold,
increased royalties from Abbott, adjustments arising from the final 1995
accounting, and the settlement agreement with Abbott.  These increases more
than offset a reduction between periods in gross profit margins and an
increase in sales and marketing, and research and development expenses.

     Joint business revenues for the third quarter of 1996 also include $0.8
million related to Chiron's 49 percent share of the operating results of a new
joint venture with Behringwerke AG.  Chiron's interest in the joint venture
was purchased in July 1996.  The results of the venture are reported on a one-
month lag.


     Collaborative agreement revenues consist of fees received for research
services as they are performed, fees received for completed research or
technology, fees received upon attainment of benchmarks specified in related
research agreements, and proceeds from sales of biological materials to
research partners for clinical and preclinical testing.  Collaborative
agreement revenues for the three-month and nine-month periods ended September
30, 1996 increased when compared to the comparable periods of 1995.  The
increase between periods is primarily attributable to revenues of $21.0
million and $52.0 million recognized during the third quarter and first nine
months of 1996, respectively, as compared to revenues of $12.0 million
recognized during the third quarter and first nine months of 1995 from
Ciba-Geigy Limited of Basel, Switzerland ("Ciba") under the terms of a
research funding agreement.  In 1995, Ciba agreed to provide $250 million
(which may be increased up to $300 million subject to certain conditions) in
support of research at Chiron.  Chiron anticipates continued utilization of
the research funding provided by Ciba under the terms of the research funding
agreement.

     Also contributing to the increase in collaborative agreement revenues are
amounts earned by Chiron's wholly

                                      20

<PAGE>

owned subsidiary, Viagene, Inc. ("Chiron Viagene") which was acquired in 
September 1995.  During the three-month and nine-month periods ended 
September 30, 1996, Chiron recognized revenues of $2.3 million and $6.9 
million, respectively, from Chiron Viagene's collaborative agreement with 
Green Cross Corporation of Japan for HIV gene therapy research and clinical 
development.  During the first nine months of 1996, Chiron also received 
initial revenues of $7.5 million from Japan Tobacco Inc. ("JT") pursuant to 
the terms of a technology transfer and development agreement whereby the 
pharmaceutical division of JT acquired a non-exclusive, perpetual license to 
apply certain of Chiron's combinatorial chemistry technologies in JT's 
research and product development programs.  In addition, during the third 
quarter of 1996, Chiron received $1.8 million from Ribozyme Pharmaceuticals 
Inc. for Chiron's expenditures on various gene therapy and delivery research 
projects.

     Other revenues consist principally of product royalties, laboratory 
services, and sales fees earned by the Company for sales and marketing 
services rendered on behalf of Ciba.  Other revenues increased in the third 
quarter and first nine months of 1996 primarily due to increased sales fees 
received from Ciba for sales of Aredia-Registered Trademark- (pamidronate 
disodium for injection), as well as increased nucleic acid probes reference 
laboratory service revenues and royalties to Chiron from Schering's European 
sales of Betaferon-TM-.   Chiron currently promotes Aredia-Registered 
Trademark- for Ciba on an exclusive basis in the U.S. under the terms of a 
contract which expires in March 1997.  Ciba has informed Chiron that Ciba 
will resume marketing of the product following the expiration of the 
contract.  Chiron and Ciba are negotiating the transition of the marketing 
responsibilities for Aredia-Registered Trademark-, including whether Chiron 
will have any ongoing role in the promotion of the product.

COSTS AND EXPENSES

     Gross profit margins during the third quarters of 1996 and 1995 remained
constant at 55 percent of product sales.  Increases in gross profit margins
resulting from the receipt of secondary revenues from Berlex's net sales of
Betaseron-Registered Trademark- and sales of immunodiagnostic assays and
branched DNA probes were offset by reduced margins resulting from sales of
clinical chemistry products and a change in the mix of vaccine product sales.
On a year-to-date basis, however, gross profit margins increased in 1996 to 57
percent from 55 percent in 1995 due to secondary revenues related to Betaseron
- -Registered Trademark- sales; improved margins arising from changes in the
sales mix of ophthalmic products and non-recurring 1995 costs resulting from
the acquisition of IOLAB; and sales of immunodiagnostic assays and branched
DNA probes.  These increases were partially offset by reduced margins
resulting from sales of clinical chemistry products, a change in the mix of
vaccine product sales and costs arising during the second quarter of 1996 of
temporarily idled manufacturing facilities in Italy.  Gross margin percentages
may fluctuate significantly in future periods as the Company's product mix
continues to evolve and as the costs of new facilities are included in cost of
goods sold.

     Research and development expenses increased slightly in the third quarter
and first nine months of 1996, as compared to 1995, partially due to the
Company's acquisition of Chiron Viagene in September 1995.  Chiron Viagene is
engaged in the discovery and development of gene transfer drugs for the
treatment of severe viral infections, cancers and other diseases and added
$4.7 million and $13.8 million of research and development expense during the
third quarter and first nine months of 1996, respectively.  In addition,
vaccine research and development expense increased by $6.8 million and $15.3
million during the third quarter and first nine months of 1996, respectively,
primarily due to Chiron's effort to obtain FDA approval of its DTaP vaccine.
During the third quarter and first nine months of 1996, diagnostic research
and development expenses increased by $7.0 million and $5.0 million,
respectively, as compared to the comparable periods in 1995, due to continued
improvements of existing immunodiagnostic instrument systems and continued
development of branched DNA probe tests, used to quantify levels of virus and
other indicators of disease.  Partially offsetting these increases is a $3.0
million reduction in September 1996 arising from the annual collaboration
accounting with G.D. Searle & Co. ("Searle"), related to research and
development costs of tissue factor pathway inhibitor products.

     Further offsetting these increases to research and development expense
during the three-month and nine-month periods ended September 30, 1996 are the
following items, recognized as research and development expense pursuant to
collaborative arrangements with other pharmaceutical and biotechnology
companies during the comparable periods in 1995:

                                      21
<PAGE>

- -    Chiron paid $16.4 million to Cephalon, Inc. in the third quarter of 1995
     related to the funding of certain collaboration expenses and the purchase
     of additional program rights;

- -    The Company paid $8.8 million to Searle for the development and marketing
     of tissue factor pathway inhibitor products;

- -    Chiron made a $3.5 million milestone payment to DepoTech Corporation
     ("DepoTech") for the research, development and marketing of products
     incorporating certain drug delivery technologies developed by DepoTech;

- -    An initial license payment of $2.5 million was paid by Chiron to
     Progenitor, Inc. ("Progenitor"), pursuant to a collaboration for the
     development and commercialization of therapeutic and vaccine products
     incorporating Progenitor's proprietary gene therapy technology;

- -    The Company reached an agreement with Genelabs Technologies, Inc.
     ("Genelabs"), whereby Chiron and Genelabs cross-licensed certain rights to
     HCV, hepatitis G virus, human T-cell leukemia virus - I and human T-cell 
     leukemia virus - II diagnostic tests.  From payments totaling $8.5 million,
     approximately $6.4 million was recognized as expense during the first nine
     months of 1995;

- -    Chiron made payments totaling $5.0 million to New York University ("NYU")
     under an agreement whereby Chiron and its sublicensee, Ciba, acquired 
     certain rights to NYU's optical gene mapping technology.

     Additionally,  Chiron, together with Johnson & Johnson ("J & J"), 
co-funded the development and introduction of a home HIV testing service 
business, Direct Access Diagnostics, and has had an option to participate as 
an equal partner with J&J in this business.  As a result of an adverse 
arbitration decision and subsequent affirming court decision, J&J must 
transfer the business and certain assets of the Direct Access Diagnostics 
business to a third party. Accordingly, Chiron does not currently expect to 
participate in the further development of this business opportunity.  The 
Company is discussing with J&J a resolution of its previous interest.

     Selling, general and administrative ("SG&A") expenses increased during 
the three-month and nine-month periods ended September 30, 1996 as compared 
to the comparable periods in 1995.  SG&A expenses in 1996 were higher due to 
selling and marketing costs to support Chiron's vaccine, immunodiagnostic and 
branched DNA probes products; Chiron's new Vitrasert-TM- Implant product; and 
due to increased costs in the ophthalmic business resulting from the 
acquisition of IOLAB, including costs related to an expanded international 
sales force. Selling and marketing expenses continue to represent the largest 
portion of total SG&A expenses, as Chiron devoted significant resources to 
support sales volumes in its product lines.

     The write-off of purchased in-process technology during the third quarter
of 1995 consists primarily of $130.3 million related to the acquisition of
Chiron Viagene in September 1995.  During the nine months ended September 30,
1995, the write-off of purchased in-process technology also consists of $222.6
million for the acquisitions from Ciba of Chiron Diagnostics Corporation
("Chiron Diagnostics"), formerly Ciba Corning Diagnostics Corp., and
Ciba's interests in Chiron Biocine and Chiron Vaccines Company ("Chiron
Vaccines"), formerly The Biocine Company; $10.3 million for the acquisition of
IOLAB; and $1.8 million from an increase in Chiron's ownership of Technolas
GmbH, a German laser ophthalmic business.

     In 1995, costs related to the Ciba transaction consist primarily of
employee payments and related tax liabilities and legal and investment advisor
fees.

     Restructuring and reorganization costs for the first nine months of 1995
represent certain accrued costs of integrating the acquired businesses with
Chiron's existing businesses, costs related to the idling of the Company's
Puerto Rico manufacturing facility and the scaling-back of manufacturing
operations at the Company's Amsterdam facility, and costs related to the
write-down of duplicate facilities at the Company's Emeryville, California,
headquarters.  Also included was a charge related to the change in plans to
expand the Company's Emeryville research and administrative facilities.

OTHER ITEMS

     Other expense, net, consists primarily of investment income on
the Company's cash and investment balances and interest expense on outstanding
debt and capital lease obligations. Other expense, net, was
negatively effected during the third quarter of 1996 by increased interest
expense as a result of increased debt borrowings, and reduced investment
income arising from lower cash balances in the Company's investment portfolio.
Comparatively, other expense, net, during the third quarter of 1995
includes a $3.0 million gain on the sale of property.  On a year-to-date
comparative basis, the other expense, net, balance reflects lower
investment income amounts.  This decrease was more than offset by a $12.2
million gain arising from the sale of the Company's

                                      22

<PAGE>

one-half interest in a generic cancer chemotherapeutics business, effective 
May 1, 1996.

     Through completion of the sale, Chiron recognized in 1996 $1.9 million of
equity in earnings of joint businesses from its one-half interest in the
generic cancer chemotherapeutics business that is described above. During the
nine months ended September 30, 1995, Chiron recognized $2.5 million of equity
in earnings.

     The provision for income taxes in the third quarter and the first nine
months of 1996 is based on an estimated annual effective income tax rate.  The
provision for income taxes during the comparable periods in 1995 was
comprised primarily of foreign taxes on certain foreign operations of the
Company.  Substantially all of the write-off of purchased in-process
technologies was not deductible for income tax purposes and thus did not
create a tax benefit in 1995.

LIQUIDITY AND CAPITAL RESOURCES

     Chiron's capital requirements are generally funded from public and
private sales of debt and equity.  In addition to these sources of capital,
future capital requirements may be financed through a combination of debt,
utilization of research funding from Ciba, possible off-balance sheet
financing (such as R&D limited partnerships and operating leases), and the use
of existing cash and investment balances.  Until required for operations,
Chiron's policy is to keep its cash and investments, which totaled
approximately $129.8 million at September 30, 1996, in a diversified portfolio
of investment grade financial instruments, including money market instruments,
corporate notes and bonds, government or government agency securities, or
other debt securities.  By policy, the amount of credit exposure to any one
institution is limited. These investments are generally not collateralized and
primarily mature within three years.  Investments with maturities in excess of
one year are presented on the balance sheet as noncurrent investments.

     Chiron attempts to reduce its exposure to fluctuations in foreign
currency exchange rates by entering into forward currency contracts
("forwards") and average rate put options ("options").  Forwards are used to
hedge balance sheet exposure resulting from completed transactions denominated
in a foreign currency, and options are used to hedge anticipated transactions.
Forward contracts are settled monthly and currently outstanding option
contracts mature within three months.  As of September 30, 1996, the Company
held forward and option contracts totaling $69.9 million and $19.1 million,
respectively.

     In future periods, Chiron expects to incur substantial capital
spending consistent with the Company's commitment to expand its manufacturing
capacity for specific products.  During the nine months ended September 30,
1996, Chiron continued the expansion of certain vaccine production facilities
in Italy as well as the expansion of its research and development and certain
administrative facilities in Emeryville.  The expansion of the Emeryville
facilities is projected to occur in stages over the next thirty years.  In
June 1996, Chiron entered into a seven-year operating lease agreement with a
group of financial institutions to rent a research and development facility to
be constructed as part of the Emeryville expansion project.  Under the terms
of this agreement, the financial institutions have committed $195.0 million
towards the total construction cost of the project.  No lease payments will
be required during the construction period which is expected to last less
than three years.

     During 1996, Chiron expanded its short-term borrowing capacity by
entering into two separate one-year revolving, unsecured credit agreements
with major financial institutions for borrowing capabilities up to $50.0
million and $100.0 million, respectively.  These facilities bring the total
committed, unsecured short-term revolving credit facilities available to the
Company in the U.S. to $200.0 million.  These credit facilities in the U.S.
are guaranteed by Ciba and provide for various borrowing rate options,
as defined in the agreements.  As of September 30, 1996, $100.0 million was
outstanding under these facilities.

     During 1996, Chiron selectively entered into cross currency interest rate
swaps ("swaps") to modify the interest and/or currency characteristics
of specific outstanding debt obligations.  During the second quarter of 1996,
Chiron entered into a one-year swap agreement with a notional amount of $24.9
million, effectively converting debt denominated in U.S. dollars to Japanese
yen and lowering the effective variable interest rate.  During July 1996,

                                      23

<PAGE>

Chiron also entered into swap agreements that mature in July 2001 with an
aggregate notional amount of $112.6 million, effectively converting debt
denominated in U.S. dollars to German marks and modifying the interest rate
from a variable rate to a fixed German mark rate of 6.2%.

     In July 1996, Chiron purchased a 49 percent interest in the human 
vaccine business of Behringwerke AG, a subsidiary of Hoechst AG.  The total 
acquisition price was $119.0 million and includes costs directly related to 
the acquisition.  This amount is subject to adjustment pending the completion 
of an audited opening balance sheet.  Under the terms of the agreement, 
Chiron has an option to purchase the remaining 51 percent interest over the 
next five years and Behringwerke AG has the option to have Chiron acquire the 
remaining interest in March 2001.  During the period of mutual ownership, 
Chiron and Behringwerke AG will operate the vaccine business as a joint 
venture, which has been named Chiron Behring.  In addition, during September 
1996, Chiron invested $30.0 million in General Injectables & Vaccines, Inc. 
("GIV") for a combination of preferred stock and debt.  GIV will distribute 
and actively promote Chiron's vaccine products in the U.S.

     Chiron's liquidity may be further impacted in future periods by its
decision to fund its share of expenses in certain of its joint ventures and
collaboration agreements.  Over the next several years, Chiron anticipates
funding collaborations with a number of research partners, and may
make additional equity investments in collaborative partners.

     During the nine months ended September 30, 1996, cash and cash
equivalents decreased by $20.4 million.  Of this amount, $10.0 million was
provided by the Company's operating activities, compared to $57.0 million used
during the nine months ended September 30, 1995.

     Investing activities consumed cash of $148.7 million during the first
nine months of 1996, versus $28.1 million in 1995.  During 1996, net sales of
marketable debt securities and capital expenditures totaled $73.6 million
and $69.5 million, respectively, versus $156.7 million and $70.6 million,
respectively, during 1995.  Additionally, in 1995 Chiron received $14.2
million, net of cash paid, through its acquisition of Chiron Diagnostics,
Chiron Biocine and Chiron Vaccines and paid $95.0 million and $35.5 million in
cash for the acquisitions of IOLAB and Viagene, respectively.  During the
first nine months of 1996, Chiron received $14.0 million from the sale of its
one-half interest in a generic cancer chemotherapeutics business and paid
$114.3 million and $30.0 million for the Company's 49 percent interest in
Chiron Behring and investment in GIV, respectively.

     Cash provided by financing activities of $118.3 million during the nine
months ended September 30, 1996 reflects cash proceeds of $36.8 million
received from the exercise of stock options and issuance of stock under the
Company's employee stock purchase plan, and increased net debt borrowings
totaling $81.4 million.  Cash provided by financing activities of $69.2
million during the comparable period in 1995 includes approximately $13.8
million of net debt borrowings, $30.6 million related to the issuance of
common stock under the Company's employee benefit plans, and a capital
contribution of $24.8 million pursuant to the 1995 agreements with Ciba.

     Chiron believes that its cash and investments, funds provided by
operations, and funding arrangements discussed above, together with Ciba's
agreement in 1995 to guarantee $425.0 million of debt for Chiron and Chiron's
option to issue up to $500.0 million of new equity to Ciba, will be sufficient
to meet its cash requirements during the upcoming twelve months and through
the foreseeable future.

FACTORS THAT MAY AFFECT FUTURE OPERATING RESULTS

        Chiron wishes to caution stockholders and investors that the following
important factors, among others, in some cases have affected, and in the
future could affect, Chiron's actual results and could cause Chiron's actual
consolidated results for the fourth quarter of 1996, and beyond, to differ
materially from those expressed in any forward-looking statements made by, or
on behalf of, Chiron.  The statements under this caption are intended to serve
as cautionary statements within the meaning of the Private Securities
Litigation Reform Act of 1995.  The following information is not intended to
limit in any way the characterization of other statements or information under
other captions as cautionary statements for such purpose:

                                      24

<PAGE>

- -      Delays, difficulties or failure in obtaining regulatory approval
       (including approval of its systems, procedures and facilities for
       production) for the Company's products.  These may include, for
       example, approval of the Company's Italian manufacturing facilities and
       processes as satisfying FDA requirements for production of the
       Company's DTaP vaccines, approval for Myotrophin, a drug under
       development by Chiron and Cephalon, Inc., for which additional clinical
       trials may be required by the FDA, and approval for Quantiplex-TM- for 
       HIV and follow-on bDNA probe products, for which the FDA may require 
       substantial additional process and systems validation.

- -      Inability to maintain or initiate third party arrangements
       which generate revenues, in the form of license fees, research and
       development support, royalties, sales fees and other payments, in
       return for rights in technology or products under development or
       promotional or other services provided by the Company.

- -      The issuance and use of patents and proprietary technology
       by Chiron and its competitors, including the possible negative effect
       on the Company's ability to develop, manufacture and sell its products
       if it is unable to obtain licenses to patents which may be required for
       such products.

- -      Delays or difficulties in developing and acquiring technology and
       technical and managerial personnel to manufacture and/or deliver the
       Company's products in commercial quantities at reasonable costs and
       in compliance with applicable quality assurance and environmental
       regulations and governmental permitting requirements.

- -      Possible changes in laws, regulations and guidelines of regulatory
       agencies, which may affect the scope, standards, timelines and sales of
       certain of the Company's products including, for example, off-label
       sales of pharmaceuticals and research use only sales of diagnostic
       instruments.

- -      The ability and willingness of customers to substitute competitive
       products for the Company's products once other products for similar
       indications are approved for marketing.

- -      Difficulties in obtaining key raw materials and supplies for the
       manufacture of the Company's products.

- -      Increased costs of development, regulatory approval, manufacture,
       sales, and marketing associated with the introduction of novel products
       and fluctuation of such costs between periods.

- -      Difficulties in launching or marketing the Company's products,
       many of which are novel products based on biotechnology, and
       unpredictability of customer acceptance of such products.

- -      Decline in the Betaseron-Registered Trademark- customer base in
       the U.S.; the extent to which patients, once enrolled, remain compliant
       with the prescribed treatment regimen and continue to regularly receive
       Betaseron-Registered Trademark-; the impact of competing products, 
       including other beta interferon products; pricing, promotional and 
       marketing decisions by the Company's partner, Schering.

- -      Continued lower product margins resulting from the Chiron-Ortho
       joint business' renegotiated contract with the American Red Cross;
       changes in the product mix whereby the proportion of higher margin HCV
       tests sold relative to other lower margin products is less;
       expanding sales of competing HCV tests by unlicensed third parties.

- -      Continued increases in research and development spending in order
       to develop new products and increase market share.

- -      Continued or increased pressure to reduce selling prices of the
       Company's products.

- -      Underutilization of the Company's existing or new manufacturing
       facilities or of any facility expansions, resulting in production
       inefficiencies and higher costs; start-up costs and inefficiencies and
       delays and increased depreciation costs in connection with the start of
       production in new plants and expansions.

- -      The cost of acquiring in-process technology, either by license,
       collaboration or purchase of another entity.

- -      Increased financing costs resulting from the expanded use of debt
       for operating and acquisition-related activities.

- -      Amount and rate of growth in Chiron's selling, general and
       administrative expenses; and the impact of unusual or infrequent
       charges resulting from Chiron's ongoing evaluation of its business
       strategies and organizational structures, including the continued costs
       of integration of newly acquired businesses.

- -      The acquisition of fixed assets and other assets, including
       inventories and receivables; and the making or incurring of any
       expenditures and expenses, including, among others, depreciation and
       research and development expenses; any revaluation of assets,
       including, among others, the Company's investments in the equity
       securities of other companies with whom it collaborates, or
       related expenses, and the amount of, and any changes to, tax rates.

                                      25

<PAGE>

- -      The ability or inability of Chiron to obtain, or hedge against,
       foreign currency, foreign exchange rates and fluctuations in those
       rates.

- -      The costs and other effects of legal and administrative cases and
       proceedings (whether civil, such as product-related or environmental,
       or criminal); settlements and investigations; developments or
       assertions by or against Chiron relating to intellectual property
       rights and licenses.

- -      Failure of corporate partners to commercialize successfully the
       Company's products or to retain and expand the markets served by the
       commercial collaborations; conflicts of interest, priorities and
       commercial strategies which may arise between the Company and such
       corporate partners.

- -      Seasonal fluctuations in product sales and resulting gross margin
       amounts.

                                      26

<PAGE>

ITEM 1.   LEGAL PROCEEDINGS.

          Information responding to Item 1 is set forth in Part 1., Item 1., 
          Notes to Consolidated Financial Statements, Note 8. "Contingencies," 
          which information is incorporated herein by reference.

ITEM 2.   CHANGES IN SECURITIES.  None.

ITEM 3.   DEFAULTS UPON SENIOR SECURITIES.  None.

ITEM 4.   SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.  None.

ITEM 5.   OTHER INFORMATION.  None.

ITEM 6.   EXHIBITS AND REPORTS ON FORM 8-K.

(a)  Exhibits.

     EXHIBIT
     NUMBER                   EXHIBIT
     -------                  -------
      2.01  Agreement and Plan of Merger, made as of February 6,
            1987, incorporated by reference to Exhibit 2.01 of the Registrant's
            Form 10-Q report for the period ended September 30, 1994.

      3.01  Restated Certificate of Incorporation of the Registrant, dated
            August 18, 1987, incorporated by reference to Exhibit 3.01 of
            the Registrant's Form 10-K report for fiscal year 1991.

      3.02  Certificate of Amendment of Restated Certificate of
            Incorporation of the Registrant, dated December 12, 1991,
            incorporated by reference to Exhibit 3.01 of the Registrant's Form
            10-K report for fiscal year 1991.

      3.03  Bylaws of the Registrant, as amended, incorporated by reference
            to Exhibit 3.03 of the Registrant's Form 10-K report for fiscal
            year 1994.

      3.04  Certificate of Amendment of Restated Certificate of
            Incorporation of the Registrant, dated May 21, 1996, incorporated by
            reference to Exhibit 3.04 of the Registrant's Form 10-Q report for
            the period ended June 30, 1996.

      4.01  Indenture, dated as of May 21, 1987, between Cetus Corporation
            and Bankers Trust Company, Trustee, incorporated by reference to
            Exhibit 4.01 of the Registrant's Form 10-Q report for the period
            ended September 30, 1994.

      4.02  First Supplemental Indenture, dated as of December 12, 1991, by
            and among Registrant, Cetus Corporation, and Bankers Trust
            Company, incorporated by reference to Exhibit 4.02 of the
            Registrant's Form 10-K report for fiscal year 1992.

      4.03  Second Supplemental Indenture, dated as of March 25, 1996, by
            and among the Registrant, Cetus Oncology Corporation (formerly
            Cetus Corporation), and Bankers Trust Company, incorporated by
            reference to Exhibit 4.03 of the Registrant's Form 10-Q report for
            the period ended June 30, 1996.

                                      27

<PAGE>

      4.04  Indenture, dated as of November 15, 1993, between Registrant
            and The First National Bank of Boston, as Trustee, incorporated by
            reference to Exhibit 4.03 of the Registrant's Form 10-K report for
            fiscal year 1993.

      4.05  Rights Agreement, dated as of August 25, 1994, between the
            Company and Continental Stock Transfer & Trust Company, which
            includes the Certificate of Designations for the Series A Junior
            Participating Preferred Stock as Exhibit A, the form of Right
            Certificate as Exhibit B and the Summary of Rights to Purchase
            Preferred Shares as Exhibit C, incorporated by reference to Exhibit
            4.04 of the Registrant's current report on Form 8-K dated 
            August 25, 1994.

      4.06  Amendment No. 1 to Rights Agreement dated as of November 20,
            1994, between Chiron Corporation and Continental Stock Transfer &
            Trust Company, incorporated by reference to Exhibit 4.05 of the
            Registrant's current report on Form 8-K, dated November 20, 1994.

      4.07  $1,000,000 County of Lorain, Ohio Variable Rate Industrial
            Revenue Bonds dated as of July 1, 1984, due July 1, 2014,
            incorporated by reference to Exhibit 4.06 of the Registrant's Form
            10-Q report for the period ended April 2, 1995. The Registrant
            agrees to furnish to the Commission upon request a copy of such
            agreement which it has elected not to file under the provisions of
            Regulation 601(b)(4)(iii).

      4.08  $1,000,000 Walpole Industrial Development Authority 6.75%
            Industrial Revenue Bonds dated as of July 1, 1979, due July 1, 2004,
            incorporated by reference to Exhibit 4.07 of the Registrant's Form
            10-Q report for the period ended April 2, 1995. The Registrant
            agrees to furnish to the Commission upon request a copy of such
            agreement which it has elected not to file under the provisions of
            Regulation 601(b)(4)(iii).

      4.09  Amendment No. 2 to Rights Agreement dated as of August 9,
            1996, between Chiron Corporation and Continental Stock Transfer &
            Trust Company, incorporated by reference to Exhibit 4.09 of the
            Registrant's Form 10-Q report for the period ended June 30, 1996.

      10.01 Lease between Registrant and BGR Associates, a California
            limited partnership, dated May 26, 1989, incorporated by reference
            to Exhibit 10.01 of the Registrant's Form 10-Q report for the period
            ended September 30, 1994.

      10.02 First Amendment to Lease between Registrant and BGR
            Associates, a California limited partnership, incorporated by
            reference to Exhibit 10.02 of the Registrant's Form 10-K report for
            fiscal year 1995.

      10.03 Lease between Registrant and BGR Associates II, a
            California limited partnership, dated May 26, 1989, incorporated by
            reference to Exhibit 10.02 of the Registrant's Form 10-Q report for
            the period ended September 30, 1994.

                                      28


<PAGE>

      10.04 First Amendment to Lease between Registrant and BGR
            Associates II, a California limited partnership, dated as of March
            15, 1995, incorporated by reference to Exhibit 10.04 of the
            Registrant's Form 10-K report for fiscal year 1995.

      10.05 Agreement and Plan of Merger dated as of April 23, 1995
            between Viagene, Inc., a Delaware corporation, and Chiron
            Corporation, incorporated by reference to Exhibit 10.67 of the
            Registrant's current report on Form 8-K dated April 24, 1995.

      10.06 Stockholders' Agreement dated as of April 23, 1995 among
            certain stockholders of Viagene, Inc., a Delaware corporation, and
            Chiron Corporation, incorporated by reference to Exhibit 10.68 of
            the Registrant's current report on Form 8-K dated April 24, 1995.

      10.07 Stock and Asset Purchase Agreement dated as of March 6,
            1995, by and among Johnson & Johnson, a New Jersey corporation, Site
            Microsurgical Systems, Inc., a Pennsylvania corporation, and Chiron
            Corporation and Amendment No. 1 to Stock and Asset Purchase
            Agreement, entered into March 31, 1995 by and among Johnson &
            Johnson, Site Microsurgical Systems, Inc. and Chiron Corporation,
            incorporated by reference to Exhibit 10.05 of the Registrant's Form
            10-Q report for the period ended April 2, 1995.

      10.08 Revolving Credit Facility dated as of March 24, 1995,
            between Chiron Corporation and Swiss Bank Corporation, San Francisco
            Branch, incorporated by reference to Exhibit 10.06 of the
            Registrant's Form 10-Q report for the period ended April 2, 1995.

      10.09 Joint Venture Agreement by and between Chiron Biocine
            Corporation, a California corporation, and CIBA-GEIGY Biocine
            Corporation, a Delaware corporation, dated April 15, 1987 (with
            certain confidential information deleted), incorporated by reference
            to Exhibit 10.23 of the Registrant's Form 8 filed with the
            Commission on February 14, 1992.

      10.10 Amendment to Biocine Joint Venture Agreement by and
            between Chiron Biocine Corporation, a California corporation, and
            CIBA-GEIGY Biocine Corporation, a Delaware corporation, effective as
            of January 1, 1992, incorporated by reference to Exhibit 10.63 to
            Registrant's Form 10-Q report for the period ended June 30, 1992.

      10.11 Research and License Agreement by and between Registrant
            and The Biocine Company, a Delaware partnership, dated April 15,
            1987 (with certain confidential information deleted), incorporated
            by reference to Exhibit 10.24 of the Registrant's Form 8 filed with
            the Commission on February 14, 1992.

      10.12 License Agreement by and between CIBA-GEIGY Biocine
            Corporation, a Delaware corporation, and The Biocine Company, a
            Delaware partnership, dated April 15, 1987 (with certain
            confidential information deleted), incorporated by reference to
            Exhibit 10.25 of the Registrant's Form 8 filed with the Commission
            on February 14, 1992.

                                      29

<PAGE>

      10.13 License Agreement by and between Chiron Biocine
            Corporation, a California corporation, and The Biocine Company, a
            Delaware partnership, dated April 15, 1987 (with certain
            confidential information deleted), incorporated by reference to
            Exhibit 10.26 of the Registrant's Form 8 filed with the Commission
            on February 14, 1992.

      10.14 Letter Agreement signed by CIBA-GEIGY Corporation, dated
            April 15, 1987, incorporated by reference to Exhibit 10.13 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.15 Agreement between the Registrant and Ortho Diagnostic
            Systems, Inc., a New Jersey corporation, dated August 17, 1989, and
            Amendment to Collaboration Agreement between Ortho Diagnostic
            Systems, Inc. and Registrant, dated December 22, 1989 (with certain
            confidential information deleted), incorporated by reference to
            Exhibit 10.14 of the Registrant's Form 10-Q report for the period
            ended September 30, 1994.

      10.16 License and Supply Agreement between Ortho Diagnostic
            Systems, Inc., a New Jersey corporation, the Registrant and Abbott
            Laboratories, an Illinois corporation, dated August 17, 1989 (with
            certain confidential information deleted), incorporated by reference
            to Exhibit 10.15 of the Registrant's Form 10-Q report for the
            quarter ended June 30, 1994.

      10.17 Chiron 1991 Stock Option Plan, as amended, incorporated by
            reference to Annex 2 of the Registrant's Proxy Statement dated 
            April 11, 1996.*

      10.18 Forms of Option Agreements, Chiron 1991 Stock Option Plan,
            as amended, incorporated by reference to Exhibit 10.17 of the
            Registrant's Form 10-K report for fiscal year 1993.*

      10.19 Form of Automatic Share Right Agreement, Chiron 1991 Stock
            Option Plan, as amended.

      10.20 Forms of Option Agreements, Cetus Corporation Amended and
            Restated Common Stock Option Plan, incorporated by reference to
            Exhibit 10.33 of Registrant's Form 10-K report for fiscal year
            1991.*

      10.21 Forms of Supplemental Letter concerning the assumption of
            Cetus Corporation options by Chiron, incorporated by reference to
            Exhibit 10.34 of Registrant's Form 10-K report for fiscal year
            1991.*

      10.22 Indemnification Agreement between the Registrant and Dr.
            William J. Rutter, dated as of February 12, 1987 (which form of
            agreement is used for each member of Registrant's Board of
            Directors), incorporated by reference to Exhibit 10.21 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.23 Stock Purchase Agreement by and between the Registrant and
            Johnson & Johnson Development Corporation, a corporation organized
            and existing under the laws of the State of New Jersey, dated as of
            October 3, 1986, incorporated by reference to Exhibit 10.22 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

                                      30

<PAGE>

      10.24 Revolving Credit Agreement, dated as of July 12, 1996,
            between Registrant and Bank of America National Trust and Savings
            Association, incorporated by reference to Exhibit 10.24 of the
            Registrant's Form 10-Q report for the period ended June 30, 1996.

      10.25 Form of Debenture Purchase Agreement between the
            Registrant and CIBA-GEIGY, Limited, a Swiss corporation, dated June
            22, 1990, incorporated by reference to Exhibit 10.25 of the
            Registrant's Form 10-K report for fiscal year 1994.

      10.26 Chiron Corporation 1.90% Convertible Subordinated Note due
            2000, Series B, incorporated by reference to Exhibit 10.25 of the
            Registrant's Form 10-K report for fiscal year 1993.

      10.27 Investment Agreement dated as of November 20, 1994 among
            Ciba-Geigy Limited, Ciba-Geigy Corporation, Ciba Biotech
            Partnership, Inc. and Chiron Corporation, incorporated by reference
            to Exhibit 10.54 of the Registrant's current report on Form 8-K
            dated November 20, 1994.

      10.28 Governance Agreement dated as of November 20, 1994 among
            Ciba-Geigy Limited, Ciba-Geigy Corporation and Chiron Corporation,
            incorporated by reference to Exhibit 10.55 of the Registrant's
            current report on Form 8-K dated November 20, 1994.

      10.29 Subscription Agreement dated as of November 20, 1994 among
            Ciba-Geigy Limited, Ciba-Geigy Corporation, Ciba Biotech
            Partnership, Inc. and Chiron Corporation, incorporated by reference
            to Exhibit 10.56 of the Registrant's current report on Form 8-K
            dated November 20, 1994.

      10.30 Cooperation and Collaboration Agreement dated as of
            November 20, 1994, between Ciba-Geigy Limited and Chiron
            Corporation, incorporated by reference to Exhibit 10.57 of the
            Registrant's current report on Form 8-K dated November 20, 1994.

      10.31 Registration Rights Agreement dated as of November 20,
            1994 between Ciba Biotech Partnership, Inc. and Chiron Corporation,
            incorporated by reference to Exhibit 10.58 of the Registrant's
            current report on Form 8-K dated November 20, 1994.

      10.32 Market Price Option Agreement dated as of November 20,
            1994 among Ciba-Geigy Limited, Ciba-Geigy Corporation, Ciba Biotech
            Partnership, Inc. and Chiron Corporation, incorporated by reference
            to Exhibit 10.59 of the Registrant's current report on Form 8-K
            dated November 20, 1994.

      10.33 Amendment dated as of January 3, 1995 among Ciba-Geigy
            Limited, Ciba- Geigy Corporation, Ciba Biotech Partnership, Inc. and
            Chiron Corporation, incorporated by reference to Exhibit 10.60 of
            the Registrant's current report on Form 8-K dated January 4, 1995.

      10.34 Supplemental Agreement dated as of January 3, 1995 among
            Ciba-Geigy Limited, Ciba-Geigy Corporation, Ciba Biotech
            Partnership, Inc. and Chiron Corporation, incorporated by reference
            to Exhibit 10.61 of the Registrant's current report on Form 8-K
            dated January 4, 1995.

                                      31


<PAGE>

      10.35 Amendment with Respect to Employee Stock Option
            Arrangements dated as of January 3, 1995 among Ciba-Geigy Limited,
            Ciba-Geigy Corporation, Ciba Biotech Partnership, Inc. and Chiron
            Corporation, incorporated by reference to Exhibit 10.62 of the
            Registrant's current report on Form 8-K dated January 4, 1995.*

      10.36 Supplemental Benefits Agreement, dated July 21, 1989,
            between the Registrant and Dr. William J. Rutter, incorporated by
            reference to Exhibit 10.27 of the Registrant's Form 10-Q report for
            the period ended September 30, 1994.*

      10.37 Lease dated as of July 1, 1983 between Cetus Corporation
            and H.B. Chapman, Jr., incorporated by reference to Exhibit 10.28 of
            the Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.38 Amendment to Lease, made as of March 20, 1990, amending
            Lease dated July 1, 1983, between Harold B. Chapman, Jr. and Cetus
            Corporation, incorporated by reference to Exhibit 10.37 of the
            Registrant's Form 10-Q report for the period ended April 2, 1995.

      10.39 Second Amendment to Lease made as of January 1, 1995
            between Harold B. Chapman, Jr. and the Registrant, incorporated by
            reference to Exhibit 10.39 of the Registrant's Form 10-K report for
            fiscal year 1995.

      10.40 Option Agreement between Harold B. Chapman, Jr., and the
            Registrant, dated January 1, 1995 and Letter dated February 28, 1996
            to Harold B. Chapman, Jr.

      10.41 Lease commencing March 1, 1987, between EuroCetus B.V. and
            the Municipal Land Company of the City of Amsterdam (Translation),
            incorporated by reference to Exhibit 10.40 of the Registrant's Form
            10-K report for fiscal year 1995.

      10.42 Form of Option Agreement (with Purchase Agreements
            attached thereto) between Cetus Corporation and each former limited
            partner of Cetus Healthcare Limited Partnership, a California
            limited partnership, incorporated by reference to Exhibit 10.31 of
            the Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.43 Form of Option Agreement (with forms of Purchase
            Agreements attached thereto), dated December 30, 1986, between Cetus
            Corporation and each former limited partner of Cetus Healthcare
            Limited Partnership II, a California limited partnership,
            incorporated by reference to Exhibit 10.32 of the Registrant's Form
            10-Q report for the period ended September 30, 1994.

      10.44 Big-O Property Purchase and Leaseback Agreement, dated as
            of October 31, 1988, between Cetus Corporation and Richard K.
            Robbins, incorporated by reference to Exhibit 10.33 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

                                      32

<PAGE>

      10.45 Triple Net Lease dated as of January 20, 1989, between
            Cetus Corporation and BGR Associates III, a California limited
            partnership, and Marin County Exchange Corporation, incorporated by
            reference to Exhibit 10.34 of the Registrant's Form 10-Q report for
            the period ended September 30, 1994.

      10.46 License Agreement between the Registrant and the Board of
            Trustees of the Leland Stanford Junior University, dated December
            15, 1981, incorporated by reference to Exhibit 10.07 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.47 Stock Purchase and Warrant Agreement dated May 9, 1989,
            between Cetus Corporation and Hoffmann-La Roche Inc., incorporated
            by reference to Exhibit 10.36 of the Registrant's Form 10-Q report
            for the period ended September 30, 1994.

      10.48 Letter Agreement, dated as of December 12, 1991, relating
            to Stock Purchase and Warrant Agreement between Registrant and
            Hoffmann-La Roche Inc., incorporated by reference to Exhibit 10.59
            of Registrant's Form 10-K report for fiscal year 1991.

      10.49 Letter Agreement dated September 26, 1990 between the
            Registrant and William G. Green, incorporated by reference to
            Exhibit 10.41 of the Registrant's Form 10-K report for fiscal year
            1992.*

      10.50 Letter Agreement dated December 18, 1991 between
            Registrant and Jack Schuler, incorporated by reference to Exhibit
            10.42 of the Registrant's Form 10-K report for fiscal year 1992.*

      10.51 Lease between Sclavo S.p.A. and Biocine Sclavo S.p.A.,
            dated January 7, 1992, incorporated by reference to Exhibit 10.49 of
            the Registrant's Form 10-Q report for the period ended April 2,
            1995.

      10.52 Agreement made as of November 11, 1993 by and between
            Kodak Clinical Diagnostics Limited, a company registered in England,
            and Ciba Corning Diagnostics Corp., a Delaware corporation, and
            Letter dated October 7, 1994 from Kodak Clinical Diagnostics Limited
            to Ciba Corning Diagnostics Corp., incorporated by reference to
            Exhibit 10.50 of Amendment No. 1 to the Registrant's Form 10-Q
            report for the period ended April 2, 1995. [Certain information has
            been omitted from the Agreement pursuant to a request by Registrant
            for confidential treatment pursuant to Rule 24b-2.]

      10.53 Regulatory Filing, Development and Supply Agreement
            between the Registrant, Cetus Oncology Corporation, a wholly-owned
            subsidiary of the Registrant, and Schering AG, a German company,
            dated as of May 10, 1993 (with certain confidential information
            deleted), incorporated by reference to Exhibit 10.50 of the
            Registrant's current report on Form 8-K dated February 9, 1994.

      10.54 Description of Executive Officer Variable Compensation
            Program, incorporated by reference to Exhibit 10.57 of the
            Registrant's Form 10-K report for fiscal year 1995.*

                                      33

<PAGE>

      10.55 Chiron Corporation 1995 Executive Officer Variable Cash
            Compensation Plan, incorporated by reference to Annex 2 of the
            Registrant's Proxy Statement dated April 18, 1995.*

      10.56 Amended and Restated License Agreement effective April 1,
            1996 between Ciba Corning Diagnostics Corp., a Delaware corporation,
            and Bioanalysis Limited, a corporation organized under the laws of
            the United Kingdom of Great Britain and Northern Ireland.  [Certain
            confidential information has been omitted from the Agreement and
            filed separately with the Securities and Exchange Commission
            pursuant to a request by Registrant for confidential treatment
            pursuant to Rule 24b-2.]

      10.57 Letter Agreement dated December 30, 1993 by and between
            Registrant and Schering AG, a German company (with certain
            confidential information deleted), incorporated by reference to
            Exhibit 10.51 of the Registrant's Form 10-K report for fiscal year
            1993.

      10.58 Guaranty, dated as of September 29, 1994, made by
            Registrant, in favor of Bankers Trust Company, as trustee,
            incorporated by reference to Exhibit 10.52 of the Registrant's Form
            10-Q report for the period ended September 30, 1994.

      10.59 Guaranty, dated as of September 29, 1994, made by Cetus
            Corporation, in favor of The First National Bank of Boston, as
            trustee, incorporated by reference to Exhibit 10.53 of the
            Registrant's Form 10-Q report for the period ended September 30,
            1994.

      10.60 Letter Agreements dated September 11, 1992, July 15, 1994
            and September 14, 1994 between the Registrant and Lewis T. Williams,
            incorporated by reference to Exhibit 10.54 of the Registrant's Form
            10-Q report for the period ended September 30, 1994.*

      10.61 Letters dated May 6, 1996 and May 25, 1996 to Magnus
            Lundberg.*

      10.62 Letter to Dino Dina dated April 24, 1984, incorporated by
            reference to Exhibit 10.66 of the Registrant's Form 10-K report for
            fiscal year 1994.*

      10.63 Research Agreement, dated as of July 15, 1985, between
            Ciba-Geigy Limited, a Swiss corporation, and Ciba Corning
            Diagnostics Corp., a Delaware corporation, incorporated by reference
            to Exhibit 10.64 of the Registrant's Form 10-Q report for the period
            ended April 2, 1995.

      10.64 Licensing Agreement, effective December 18, 1986, by and
            between Miles Laboratories, Inc., a Delaware corporation, and Ciba
            Corning Diagnostics Corp., a Delaware corporation, and Letter dated
            December 18, 1992 from Ciba Corning Diagnostics Corp. to Miles
            Laboratories, Inc., incorporated by reference to Exhibit 10.65 of
            Amendment No. 1 to the Registrant's Form 10-Q report for the period
            ended April 2, 1995.[Certain information has been omitted from the
            Agreement pursuant to a request by Registrant for confidential
            treatment pursuant to Rule 24b-2.]

                                      34


<PAGE>

      10.65 Magnetocluster Binding Assay Technology Agreement, dated
            as of January 21, 1983, by and between Bioclinical Group, Inc., a
            Delaware corporation, and Corning Glass Works, a New York
            corporation, incorporated by reference to Exhibit 10.66 of Amendment
            No. 1 to the Registrant's Form 10-Q report for the period ended
            April 2, 1995.  [Certain information has been omitted from the
            Agreement pursuant to a request by Registrant for confidential
            treatment pursuant to Rule 24b-2.]

      10.66 Turn-back License Agreement, dated as of May 30, 1986, by
            and between Ciba Corning Diagnostics Corp., a Delaware corporation,
            and Advanced Magnetics, Inc., a Delaware corporation, incorporated
            by reference to Exhibit 10.67 of the Registrant's Form 10-Q report
            for the period ended April 2, 1995. [Certain information has been
            omitted from the Agreement pursuant to a request by Registrant for
            confidential treatment pursuant to Rule 24b-2.]

      10.67 Settlement Agreement, dated August 30, 1989, between Ciba
            Corning Diagnostics Corp. and Advanced Magnetics, Inc., incorporated
            by reference to Exhibit 10.68 of the Registrant's Form 10-Q report
            for the period ended April 2, 1995.  [Certain information has been
            omitted from the Agreement pursuant to a request by Registrant for
            confidential treatment pursuant to Rule 24b-2.]

      10.68 Lease made and entered into December 17, 1984 between BGR
            Associates, a California limited partnership, and Cetus Corporation
            and Amendment to Lease dated December 17, 1984, entered into
            effective February 1, 1986, incorporated by reference to Exhibit
            10.69 of the Registrant's Form 10-Q report for the period ended
            April 2, 1995.

      10.69 Second Amendment to Lease dated as of March 15, 1995
            between BGR Associates, a California limited partnership, and
            Registrant, incorporated by reference to Exhibit 10.73 of the
            Registrant's Form 10-K report for fiscal year 1995.

      10.70 Agreement, effective as of December 21, 1988, by and
            between Hoffmann-La Roche Inc., a New Jersey corporation, and Cetus
            Corporation, incorporated by reference to Exhibit 10.70 of the
            Registrant's Form 10-Q report for the period ended April 2, 1995.
            [Certain information has been omitted from the Agreement pursuant to
            a request by Registrant for confidential treatment pursuant to Rule
            24b-2.]

      10.71 Agreement, effective as of December 21, 1988, by and among
            F. Hoffmann-La Roche Ltd., a Swiss corporation, Cetus Corporation,
            and EuroCetus International, B.V., a Netherlands Antilles
            corporation, incorporated by reference to Exhibit 10.71 of the
            Registrant's Form 10-Q report for the period ended April 2, 1995.
            [Certain information has been omitted from the Agreement pursuant to
            a request by Registrant for confidential treatment pursuant to Rule
            24b-2.]

                                      35

<PAGE>

      10.72 Agreement, by and between Cetus Oncology Corporation,
            EuroCetus International, N.V., and F. Hoffmann-La Roche Ltd.,
            incorporated by reference to Exhibit 10.72 of the Registrant's Form
            10-Q report for the period ended April 2, 1995. [Certain information
            has been omitted from the Agreement pursuant to a request by
            Registrant for confidential treatment pursuant to Rule 24b-2.]

      10.73 Agreement commencing January 1, 1991, between EuroCetus
            B.V. and the Municipal Development Corporation (Translation),
            incorporated by reference to Exhibit 10.41 of the Registrant's Form
            10-K report for fiscal year 1994.

      10.74 Settlement Agreement on Purified IL-2, made as of April
            14, 1995, by and between Cetus Oncology Corporation, dba Chiron
            Therapeutics, a Delaware corporation, and Takeda Chemical
            Industries, Ltd., a Japanese corporation, incorporated by reference
            to Exhibit 10.74 of the Registrant's Form 10-Q report for the period
            ended July 2, 1995.  [Certain information has been omitted from the
            Agreement pursuant to a request by Registrant for confidential
            treatment pursuant to Rule 24b-2.]

      10.75 License Agreement made and entered into December 1, 1987,
            by and between Sloan Kettering Institute for Cancer Research, a
            not-for-profit New York corporation, and Cetus Corporation,
            incorporated by reference to Exhibit 10.75 of the Registrant's Form
            10-Q report for the period ended July 2, 1995.  [Certain information
            has been omitted from the Agreement pursuant to a request by
            Registrant for confidential treatment pursuant to Rule 24b-2.]

      10.76 Chiron Funding L.L.C. Limited Liability Company Agreement,
            entered into and effective as of December 28, 1995, among the
            Registrant, Chiron Biocine Company and Biocine S.p.A. and Ciba-Geigy
            Corporation, incorporated by reference to Exhibit 10.80 of the
            Registrant's Form 10-K report for fiscal year 1995. [Certain
            information has been omitted from the Agreement and filed separately
            with the Securities and Exchange Commission pursuant to a request by
            Registrant for confidential treatment pursuant to Rule 24b-2.  The
            omitted confidential information has been identified by the
            following statement: "Confidential Treatment Requested".]

      10.77 Agreement between Ciba-Geigy Limited and the Registrant
            made November 15, 1995, incorporated by reference to Exhibit 10.81
            of the Registrant's Form 10-K report for fiscal year 1995.  [Certain
            information has been omitted from the Agreement and filed separately
            with the Securities and Exchange Commission pursuant to a request by
            Registrant for confidential treatment pursuant to Rule 24b-2.  The
            omitted confidential information has been identified by the
            following statement: "Confidential Treatment Requested".]

      10.78 Reimbursement Agreement dated as of March 24, 1995,
            between Ciba-Geigy Limited, a Swiss corporation, and the Registrant,
            incorporated by reference to Exhibit 10.76 of the Registrant's Form
            10-Q report for the period ended July 2, 1995.

                                      36

<PAGE>


      10.79 Promissory Note, as amended and restated, dated January 1,
            1995 by Ciba Corning Diagnostics Corp., incorporated by reference to
            Exhibit 10.83 of the Registrant's Form 10-K report for fiscal year
            1995.

      10.80 Commercial lease between Domilyon Corporation and Domilens
            Laboratories and Amendment No. 1 to Commercial Lease dated May 9,
            1994, incorporated by reference to Exhibit 10.84 of the Registrant's
            Form 10-K report for fiscal year 1995.

      10.81 Agreement between the Registrant and Cephalon, Inc. dated
            as of January 7, 1994, and Letter Agreements between the Registrant
            and Cephalon dated January 13, 1995 and May 23, 1995, incorporated
            by reference to Exhibit 10.85 of the Registrant's Form 10-K report
            for fiscal year 1995.  [Certain information has been omitted from
            the Agreements and filed separately with the Securities and Exchange
            Commission pursuant to a request by Registrant for confidential
            treatment pursuant to Rule 24b-2.  The omitted confidential
            information has been identified by the following statement:
            "Confidential Treatment Requested".]

      10.82 Reimbursement Agreement, dated as of June 28, 1996,
            between Ciba-Geigy Limited, a Swiss corporation, and the Registrant,
            incorporated by reference to Exhibit 10.94 of the Registrant's Form
            10-Q report for the period ended June 30, 1996.

      10.83 Reimbursement Agreement, dated as of May 20, 1996, between
            Ciba-Geigy Limited, a Swiss corporation, and the Registrant,
            incorporated by reference to Exhibit 10.95 of the Registrant's Form
            10-Q report for the period ended June 30, 1996.

      10.84 Letter Agreement between the Registrant and Dr. Richard W.
            Barker dated May 1, 1996, incorporated by reference to Exhibit 10.88
            of the Registrant's Form 10-Q report for the period ended June 30,
            1996.*

      10.85 Revolving Credit Agreement, dated as of March 23, 1996,
            between the Registrant and Morgan Guaranty Trust Company of New
            York, incorporated by reference to Exhibit 10.89 of the Registrant's
            Form 10-Q report for the period ended June 30, 1996.

      10.86 Purchase and Assignment Agreement between Behringwerke
            Aktiengesellschaft, on the one side, and 31. CORSA
            Verwaltungsgesellschaft mbH and the Registrant, on the other side,
            dated February 17, 1996, Closing Agreement, by and among
            Behringwerke Aktiengesellschaft, on the one side, and the Registrant
            and 31. CORSA Verwaltungsgesellschaft mbH, on the other side, dated
            June 29, 1996 and Letter Agreement dated June 29, 1996 between the
            Registrant, 31. CORSA Verwaltungsgesellschaft mbH and Behringwerke
            Aktiengesellschaft. [Certain confidential information has been
            omitted from the Agreements and filed separately with the Securities
            and Exchange Commission pursuant to a request by Registrant for
            confidential treatment pursuant to Rule 24b-2.]

                                      37

<PAGE>


      10.87 Royalty Projects Agreement by and between Ciba Corning
            Diagnostics Corp., a Delaware corporation, and Ciba-Geigy Limited, a
            Swiss corporation. [Certain confidential information has been
            omitted from the Agreement and filed separately with the Securities
            and Exchange Commission pursuant to a request by Registrant for
            confidential treatment pursuant to Rule 24b-2.]

      10.88 Purchase Agreement between BNP Leasing Corporation and the
            Registrant, dated June 28, 1996, incorporated by reference to
            Exhibit 10.90 of the Registrant's Form 10-Q report for the period
            ended June 30, 1996.


      10.89 Lease Agreement between BNP Leasing Corporation and the
            Registrant, dated June 28, 1996, incorporated by reference to
            Exhibit 10.91 of the Registrant's Form 10-Q report for the period
            ended June 30, 1996.

      10.90 Ground Lease between BNP Leasing Corporation and the
            Registrant, dated June 28, 1996, incorporated by reference to
            Exhibit 10.92 of the Registrant's Form 10-Q report for the period
            ended June 30, 1996.

      10.91 Reimbursement Agreement, dated as of July 12, 1996,
            between Ciba-Geigy Limited, a Swiss corporation, and the Registrant,
            incorporated by reference to Exhibit 10.93 of the Registrant's Form
            10-Q report for the period ended June 30, 1996.

      11    Statement of Computation of Earnings per Share.

      27    Financial Data Schedule.

- ------------------------------------------
*Management contract, compensatory plan or arrangement.

(b)    Reports on Form 8-K

     None.

                                      38

<PAGE>

                              CHIRON CORPORATION

                              September 30, 1996




                                  SIGNATURES


     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.




                                           CHIRON CORPORATION



DATE: November 12, 1996                    BY: /s/ Edward E. Penhoet
      ---------------------------------        --------------------------------
                                               Edward E. Penhoet
                                               President and Chief
                                               Executive Officer



DATE: November 12, 1996                    BY: /s/ Dennis L. Winger
      ---------------------------------        --------------------------------
                                               Dennis L. Winger
                                               Senior Vice President, 
                                               Finance and Administration,
                                               Chief Financial Officer, and
                                               Principal Accounting Officer

                                      39

<PAGE>

                                        [Date]
                                           
[Director name and address]



                   Re: Automatic Share Right Grant

Dear [        ]:

                 Pursuant to the Chiron 1991 Stock Option Plan (the "Plan"), 
Chiron Corporation (the "Company") hereby grants you [     ] restricted share 
rights ("share rights") with respect to its Common Stock ("Common Stock") 
effective[                 ] ("Grant Date").  These share rights are granted to
you in accordance with the terms of this letter and the provisions of the Plan.

                 1.   Each share right entitles you to receive one share of 
Common Stock on the date that the share right vests in accordance with 
paragraph 2 (the "Vesting Date"), if you continue to provide services to the 
Company or its subsidiaries as a director, an employee, a consultant or an
independent contractor through such date.  A certificate representing the 
shares of Common Stock will be issued without restriction on or as soon as 
practicable following the Vesting Date of the share right, provided that such 
share right has not been terminated or canceled before such date.

    Your share rights will vest in five equal annual installments on each of
the first five anniversaries of the Grant Date, provided that, in each case, you
continue to provide services to the Company or its subsidiaries as a director,
an employee, a consultant or an independent contractor through such date.  In
addition, if you terminate your service with the Company by reason of death or
Permanent Disability (as defined below), all your outstanding share rights will
immediately vest in full.  If you cease to provide services to the Company or
its subsidiaries as a director, an employee, a consultant or an independent
contractor for any reason other than death or Permanent Disability, any share
right held by you that has not vested before the date of your termination of
such services will be canceled automatically and will no longer be outstanding
and no shares of Common Stock will be issued hereunder.  "Permanent Disability"
means your inability to engage in any substantial gainful activity by reason of
any medically determinable 

<PAGE>

                                                                         Page 2

physical or mental impairment which is expected to result in death or has lasted
or can be expected to last for a continuous period of twelve (12) months or 
more.  In the event of an agreement to dispose of all or substantially all of
the assets or outstanding capital stock of the Company by means of a sale,
merger, reorganization, or liquidation, all of your outstanding share rights
will immediately vest.  However, no acceleration of vesting will occur if the
terms of the agreement require as a prerequisite to the consummation of any such
sale, merger, reorganization or liquidation that your share rights will be
either assumed by the successor corporation or parent thereof or be replaced
with a comparable award subject to shares of the successor corporation or parent
thereof.  Upon consummation of the sale, merger, reorganization or liquidation
contemplated by the agreement, share rights, whether or not accelerated, will
terminate unless assumed pursuant to a written agreement by the successor
corporation or parent thereof.

              Your share rights hereunder may not be sold, assigned,
transferred, alienated, subject to garnishment or otherwise encumbered in any
manner other than by transfer by will or the laws of descent and distribution. 
In the event of your death before the issuance of shares of Common Stock under
your share rights, any shares issuable thereunder by reason of your death will
pass pursuant to your will or by the laws of descent and distribution.

              The issuance of shares of Common Stock hereunder is subject to
the procurement by the Company of all approvals and permits required by
regulatory authorities having jurisdiction over the share rights and stock to be
issued hereunder.  The inability of the Company to obtain approval from any
regulatory body having authority deemed by the Company to be necessary to the
lawful issuance of any Common Stock hereunder will relieve the Company of any
liability with respect to the non-issuance of the Common Stock as to which such
approval is not obtained.  The Company, however, will use its best efforts to
obtain all such approvals.

              If any change is made to the Common Stock issuable hereunder by
reason of any stock split, stock dividend, recapitalization, combination of
shares, exchange of shares or other change affecting the outstanding Common
Stock as a class without receipt of consideration, the Compensation Committee of
the Board of Directors of the Company (the "Compensation Committee") will make
appropriate adjustments to such share rights to prevent the enlargement or
dilution of your rights thereunder.

              Neither you nor, in the event of your death, your beneficiary
will have any rights as a shareholder with respect to the shares of Common Stock
issuable hereunder until you have been issued a stock certificate for such
shares.  It is the intention of the parties that the Company's obligations under
your share rights are unfunded for purposes of the Internal Revenue Code and
that the Employee Retirement Income Security Act of 1974 does not apply to your
share rights.

              This agreement does not constitute a contract of employment or
services.  Neither the grant of this share right, nor any action taken under the
terms of this share right or the Plan, nor any provision of this share right or
the Plan will be construed to grant you the right to remain in the employ or
service of the Company (or any subsidiary or parent of the Company) for any
period of specific duration.

<PAGE>

                                                                          Page 3

    If the foregoing is satisfactory, please sign, date, and return the enclosed
copy of this letter to_______________________________________________

                                                       Very truly yours,

                                                       CHIRON CORPORATION

                                                       By 
                                                          --------------------





AGREED AND ACCEPTED: 

- ----------------------

[Director] 


<PAGE>



                            OPTION AGREEMENT
                            ----------------


                                 between



                         HAROLD B. CHAPMAN, JR.,

                               ("Seller")



                                   and



                           CHIRON CORPORATION

                                ("Buyer")




<PAGE>
                            OPTION AGREEMENT
                            ----------------

     THIS OPTION AGREEMENT ("Agreement") is entered as of January 1, 1995
("Effective Date") by and between HAROLD B. CHAPMAN, JR., an individual
("Seller"), and CHIRON CORPORATION, a Delaware corporation ("Buyer").

     THE PARTIES ENTER THIS AGREEMENT on the basis of the following facts,
understandings and intentions of the parties:

     A.   Seller is owner of the real property more particularly described on 
EXHIBIT A, attached hereto, together with all improvements thereon, including 
the buildings known as Buildings "M" and "G", and all appurtenances thereto 
(collectively, the "Property").  The Property is more particularly described 
in the Lease (as defined in Recital B).

     B.   Buyer (as successor to Cetus Corporation) currently leases the 
Property from Seller pursuant to a lease agreement ("Original Lease") dated 
as of July 1, 1983, as amended by (i) the Amendment to Lease ("First 
Amendment to Lease") dated as of March 20, 1990, and (ii) the Second 
Amendment to Lease dated as of January 1, 1995. The Original Lease, as 
amended by the First Amendment to Lease and the Second Amendment to Lease, is 
hereinafter referred to as the "Lease".  A copy of the Lease is attached 
hereto as EXHIBIT B.

     C.   Buyer desires to obtain an option ("Option") to purchase the
Property from Seller, and Seller is willing to grant to Buyer an Option to
purchase the Property, upon all of the terms, covenants and conditions of
this Agreement.

     NOW, THEREFORE, in consideration of the mutual covenants and promises of
the parties, the parties hereto agree as follows:

     1.   GRANT OF OPTION. Seller grants to Buyer the Option to purchase
the Property on the terms of this Agreement.

     2.   OPTION TERM. The term of the Option ("Option Term") shall be five
(5) years, commencing as of the Effective Date.  There shall be no
extension of the Option Term except by a written executed agreement by
Seller and Buyer.

     3.   CONSIDERATION.

          a.   OPTION PAYMENT; SECOND AMENDMENT TO LEASE.
As consideration for the Option, Buyer shall pay Seven Hundred Fifty
Thousand Dollars ($750,000.00) ("Option Payment") to Seller.


                                      1.
<PAGE>

          b.   TIME OF PAYMENT.  The Option Payment shall be made within five 
(5) days after (i) execution of the Second Amendment to Lease (to the extent 
not previously executed); (ii) execution of this Agreement by Seller and 
Buyer; and (iii) recordation of the Memorandum of Option (as provided in 
Section 18.a), which shall be recorded by Buyer within five (5) days after 
the last execution of the documents referred to in Sections (i) and (ii) of 
this Section 3.b.

          c.   OPTION PAYMENT EARNED. The Option Payment shall be deemed 
earned in full upon (i) execution of this Agreement, (ii) execution of all 
documents required to be executed concurrently with execution of this 
Agreement, and (iii) completion of all of the items listed in Section 3.b.

          d.   RETENTION OF OPTION CONSIDERATION. If Buyer  fails to exercise 
the Option, Seller shall retain the Option Payment.

          e.   APPLICATION OF OPTION PAYMENT. If the Option is exercised, the 
Option Payment shall be applied as a credit against the Purchase Price.

     4.   EXERCISE.

          a.   EXERCISE NOTICE.  If not then in breach of this Agreement, Buyer
shall have the right to exercise the Option prior to the expiration of the 
Option Term by delivering a written notice ("Exercise Notice") to Seller by 
registered mail or personal delivery stating that Buyer desires to close 
Escrow (as hereinafter defined).  The date of the closing of Escrow shall be 
determined by Seller in accordance with the terms of Section 11.a.

          b.   AGREEMENT FOR PURCHASE AND SALE. Upon the exercise of the 
Option, this Agreement shall become a contract for the purchase and sale of 
the Property, and Buyer shall thereupon agree to buy and Seller shall 
thereupon agree to sell the Property, upon all of the terms, covenants and 
conditions set forth in this Agreement.

          c.   EXTENSION OF LEASE.  If Buyer delivers the Exercise Notice and 
the close of Escrow is to occur after the date the Lease would have expired 
if there were no further extension, Optionee shall be deemed to have 
exercised the right to extend the Lease for a period of two (2) years (I.E., 
from July l, 2000 to June 31, 2002).  Extension of the Lease pursuant to this 
Section 4.c shall not be affected if close of Escrow does not occur.

                                      2.

<PAGE>

     5.   PURCHASE PRICE.

          a.   AMOUNT.  If the Option is exercised, Buyer shall deliver to 
Chicago Title Insurance Company ("Escrow Agent") prior to the close of Escrow 
("Close of Escrow") cash or other readily available funds in the amount of 
Ten Million Five Hundred Thousand Dollars ($10,500,000.00) ("Purchase 
Price"), subject to any adjustment pursuant to Section 5.c, reduced by 
credits for (i) the amount of the Option Payment; and (ii) amounts necessary 
to remove any liens against the Property, other than the Permitted Exceptions 
(as hereinafter defined), which are caused by Seller.

          b.   CPI.  For purposes of this Section 5, the "CPI" shall mean the 
Consumer Price Index (CPI) for All Urban Consumers, All Items, for the San 
Francisco-Oakland Metropolitan Area (1982-84 = 100), as published by the 
Bureau of Labor Statistics of the United States Department of Labor 
("Bureau").  If the Bureau discontinues publication of the CPI, publishes the 
CPI less frequently, or alters the CPI in any manner, Buyer shall adopt a 
substitute CPI procedure which Buyer and Seller feel reasonably reflects and 
monitors the consumer prices.

          c.   CPI ADJUSTMENT.  The Purchase Price shall increase by the 
percentage increase in the CPI in excess of five percent (5%) per annum from 
the date of this Agreement to the date of the Exercise Notice.  For example, 
(i) if the period between the date of this Agreement and the date of the 
Exercise Notice is four (4) years, and (ii) the CPI increases by twenty-three 
percent (23%) during the four (4) year period, then the Purchase Price shall 
increase by three percent (3%) to Ten Million Eight Hundred Fifteen Thousand 
Dollars ($10,815,000.00).

     6.   REPRESENTATIONS OF SELLER. Seller hereby makes the following 
representations and warranties for the benefit of Buyer (which 
representations are made by Seller as of both the date of this Agreement and 
as of the Closing Date):

          a.   NO ADDITIONAL LEASES. Except for the Lease, (i) there are no 
leases of all or any portion of the Property, and (ii) Seller has not 
entered, nor is Seller aware that any other person or entity other than Buyer 
has entered, any other agreements affecting the occupancy of the Property.

          b.   NO LITIGATION.  Except as described in Exhibit C, attached 
hereto, there are no civil, governmental, quasi-governmental or 
administrative investigations, actions, suits, proceedings or claims pending 
or, to the best of Seller's knowledge, threatened against or affecting Seller 
or the Property (including the use, occupancy, operation or value of the

                                      3.
<PAGE>

Property).  Seller does not know of any basis for any such investigations,
actions, suits, proceedings or claims.

          c.   OWNERSHIP OF PROPERTY. Seller is the owner of the Property and 
has the authority, acting alone, to enter this Agreement and to convey title 
to the Property in accordance with this Agreement.

          d.   NO ADDITIONAL REPRESENTATIONS.  Seller makes no warranties 
whatsoever except those specifically set forth in this Agreement.

     7.   INSPECTIONS.

          a.   INSPECTION RIGHTS.  During the Option Period, Buyer shall have 
the right to conduct any and all studies, tests (including environmental 
tests) and inspections that Buyer deems appropriate to determine the 
condition and status of the Property.

          b.   WAIVER BY BUYER.  Purchase of the Property pursuant to 
exercise of the Option by Buyer shall constitute a waiver by Buyer of any 
defects in either the title or the physical condition of the Property 
(including the improvements comprising part of the Property).  Purchase of 
the Property pursuant to exercise of the Option constitutes acceptance by 
Buyer of the Property in an "as is" condition.

     8.   COOPERATION OF SELLER.

          a.   RIGHT OF BUYER. During the Option Term, Buyer shall have the 
right to apply for and obtain all Approvals (as defined below) relating to 
the Property which Buyer desires from governmental agencies, 
quasi-governmental agencies, and other entities and persons having authority 
over the Property.  The Approvals may relate to Buyer's plans to develop the 
Property, together with other property located near the Property, with a new 
life science facility.  To the extent requested by Buyer, Seller shall assist 
Buyer in obtaining the Approvals.

          b.   SCOPE OF ASSISTANCE.  Seller's assistance shall include 
execution of all applications for Approvals which Buyer requests Seller to 
execute and, when required by the City of Emeryville ("City"), recordation 
against the Property of any Approvals obtained by Buyer for development of 
the Project.

          c.   APPROVALS.  The Approvals may include (i) a development 
agreement; (ii) a participation agreement under redevelopment law; (iii) a 
vesting tentative map and any final subdivision maps pursuant to the vesting 
tentative map; (iv) a

                                      4.



<PAGE>

planned unit development and other zoning approvals; and (v) a General Plan
amendment.

          d.   REIMBURSEMENT OF SELLER. For time spent at Buyer's request, in 
activities necessary for Buyer to obtain the Approvals, Seller shall be 
entitled to (i) Two Hundred Dollars ($200.00) per hour and (ii) reimbursement 
for reasonable out-of-pocket costs and expenses incurred by Seller.  Buyer 
shall notify Seller before Buyer commences activities for which Seller will 
seek payment or reimbursement totalling more than Two Thousand Dollars 
($2,000.00).

          e.   OBLIGATION OF BUYER.  Buyer shall indemnify Seller against any 
net reduction in the value of the Property, or net increase in the costs paid 
by Seller, resulting from the conditions imposed against the Property 
pursuant to the Approvals if (i) the Approvals reduce the value of the 
Property and (ii) for any reason other than default by Seller, Buyer does not 
exercise the Option and purchase the Property.

     9.   TITLE ISSUES.

          a.   PERMITTED EXCEPTIONS.  For purposes of this Agreement, the 
term "Permitted Exceptions" shall mean (i) the exceptions to title recorded 
against the Property as of January 12, 1995, as shown in the Preliminary 
Report (Order No. 105494), dated as of January 12, 1995 and issued by Chicago 
Title Company of Alameda County, a copy of which is attached hereto as 
EXHIBIT D, exclusive of the deed of trust ("Home Savings Deed of Trust") for 
the benefit of Home Savings of America, F.A. ("Home Savings"), and (ii) any 
exceptions created by Buyer after the Effective Date.

          b.   DEED.  Seller shall convey title to the Property to Buyer by a 
standard grant deed ("Deed").

          c.   TITLE POLICY.  At the Close of Escrow, Title Company shall 
issue to Buyer, upon payment of Title Company's regularly scheduled premium, 
an ALTA owner's extended coverage policy of title insurance ("Title Policy"), 
in the amount of the Purchase Price, showing title vested in Buyer, subject 
only to the Permitted Exceptions and the standard printed exceptions in the 
Title Policy.  The Title Policy shall contain such endorsements as Buyer 
desires.

     10.  ESCROW. Buyer shall establish the escrow ("Escrow") for the close 
of this transaction at the office of Title Company after Buyer delivers the 
Exercise Notice.  Prior to the Close of Escrow, the parties shall deposit the 
following funds and documents into Escrow, and Title Company shall close 
Escrow as provided below.


                                      5.
<PAGE>

          a.   SELLER. Seller shall deposit into Escrow the following: 

               (i)   DEED.  The duly executed and acknowledged Deed;

               (ii)  NON-FOREIGN CERTIFICATE. A duly executed certificate 
("Non-Foreign Certificate") from Seller certifying that Seller is not a 
"foreign person" within the meaning of Section 1445(f)(3) of the Internal 
Revenue Code ("Code"), to the extent Seller is so qualified;

               (iii) SELLER'S CERTIFICATE. A duly executed certificate from 
Seller stating that the warranties and representations of Seller which are 
made under this Agreement are valid as of the Closing Date;

               (iv)  RECONVEYANCE DOCUMENTS. All documents necessary to 
reconvey any mortgages and deeds of trust that are then of record against the 
Property ("Deeds of Trust"); and

               (v)   FUNDS.  All funds necessary to reconvey the Deeds of 
Trust to the extent (A) the proceeds due to Seller upon the sale are 
insufficient to pay off all of the obligations secured by the Deeds of Trust 
and (B) the Deeds of Trust are secured by Seller's (and not Buyer's) interest 
in the Property.

          b.   BUYER: Buyer shall deposit into Escrow the following:

               (i)   PURCHASE PRICE.  The Purchase Price, subject to the 
adjustments described in Section 5 (and possible credits under Sections 12 
and 13); and

               (ii)  ADDITIONAL CASH. Additional cash in the amount necessary 
to pay all Escrow costs and prorations, as hereinafter set forth.

     11.  CLOSE OF ESCROW.

          a.   CLOSING DATE. Close of Escrow ("Close of Escrow") shall occur 
on the date ("Closing Date") determined by Seller; provided that (i) the 
Closing Date shall be within one (1) year after the date of the Exercise 
Notice, (ii) the Closing Date shall not be less than six (6) months after the 
date of the Exercise Notice and (iii) Seller shall give Buyer not less than 
forty-five (45) days' prior written notice of the Closing Date. When Title 
Company is in a position to issue the Title Policy and all documents and 
funds have been deposited with Title Company, Title Company shall close 
Escrow as provided below.  The failure


                                      6.
<PAGE>

of Seller or Buyer to be in a position to close Escrow by the Closing Date
shall be a default under this Agreement.

          b.   PROCEDURE.  Title Company shall close Escrow as follows:

               (i)   RECORD DEED.  Record the Deed and deliver the Deed to 
Buyer;

               (ii)  DELIVER PURCHASE PRICE.  Deliver the Purchase Price to 
Seller by federal wire transfer or cashier's check, or as instructed by 
Seller, reduced by the credits to Buyer described in Section 5 (and possible 
credits under Sections 12 and 13) and Seller's share of costs and prorations 
as provided below; and

               (iii) DELIVER TITLE POLICY.  Deliver the Title Policy to Buyer.

          c.   COSTS AND PRORATIONS.

               (i)   CLOSING COSTS. Buyer and Seller each shall pay its own 
attorneys' fees. Buyer shall pay all Escrow fees, recording costs, title 
insurance premiums and documentary transfer taxes.

               (ii)  PRORATIONS. Real estate taxes and assessments (both 
principal and interest) shall be the obligation of Chiron.

          d.   INCORPORATION. The parties shall execute for the benefit of 
Title Company such additional Escrow instructions as Title Company shall 
require, provided that the additional Escrow instructions do not modify or 
alter the terms of this Agreement.

     12.  EMINENT DOMAIN.

          a.   CREDIT OR ASSIGNMENT OF PROCEEDS.  If there is an exercise of 
the power of eminent domain by a governmental agency in regard to all or any 
portion of the Property, all the proceeds from the eminent domain action 
(with interest at the rate of five percent (5%) per annum from the date the 
proceeds are received by Seller to the Closing Date) shall be credited 
against the Purchase Price (subject to the limitation in Section 12.b). If 
the proceeds from the eminent domain action have not been paid to Seller as 
of the Closing Date, Seller shall assign to Buyer all rights to the proceeds 
(subject to the limitation in Section 12.b), including the sole right to 
settle or approve the settlement of any eminent domain action.


                                      7.
<PAGE>

          b.   LIMITATION ON CREDIT OR ASSIGNMENT.  The maximum amount of the 
proceeds credited to the Purchase Price or assigned by Seller to Buyer under 
Section 12.a shall be the Purchase Price, with Seller to retain the right to 
receive the balance of the proceeds, unless Buyer delivers the Exercise 
Notice to Seller prior to expiration of the Option Term.

     13.  DAMAGE AND DESTRUCTION.

          a.   CREDIT OR ASSIGNMENT OF INSURANCE PROCEEDS. If there is damage 
or destruction of all or any portion of the Property, all of the insurance 
proceeds paid to Seller in connection with the restoration of the Property 
(with interest at the rate of five percent (5%) per annum from the date the 
insurance proceeds are received by Seller to the Closing Date) shall be 
credited against the Purchase Price (subject to the limitation in Section 
13.b). If the insurance proceeds have not been paid as of the Closing Date, 
Seller shall assign to Buyer all the rights to the insurance proceeds 
(subject to the limitation in Section 13.b), including the sole right to 
settle or approve the settlement of any action against the insurer.

          b.   LIMITATION ON CREDIT OR ASSIGNMENT. The maximum amount of the 
insurance proceeds credited to the Purchase Price or assigned by Seller to 
Buyer under Section 13.a shall be the Purchase Price, with Seller to retain 
the right to receive the balance of the insurance proceeds, unless Buyer 
delivers the Exercise Notice to Seller prior to expiration of the Option Term.

     14.  TAX DEFERRED EXCHANGE.

          a.   COOPERATION; INDEMNITY. To the extent requested by Seller, 
Buyer shall cooperate with Seller in effecting the transfer of the Property 
as an exchange in accordance with Section 1031 of the Code.  Seller shall 
indemnify, defend, protect and hold harmless Buyer for all costs, expenses, 
liabilities and claims arising out of the exchange.  Any such exchange shall 
not delay the Close of Escrow, require Buyer to incur any additional costs or 
expenses (except as provided in Section 14.b), or require Buyer to take title 
to any replacement property for the benefit of Seller.

          b.   REIMBURSEMENT BY SELLER. Seller shall reimburse Buyer for all 
additional costs and  expenses resulting from Seller effecting the transfer 
of the Property as an exchange under Section 1031 of the Code (I.E., costs 
and expenses in addition to the costs and expenses Buyer would have incurred 
if the transfer were a sale).  Buyer shall not incur in excess of Five 
Thousand Dollars ($5,000.00) of additional costs and expenses for which Buyer 
will seek reimbursement from Seller without Seller's prior consent.


                                      8.
<PAGE>

     15.  BROKERAGE COMMISSION. Buyer and Seller each warrants for the 
benefit of the other that no brokerage commission or finder's fee shall be 
due with respect to the sale of the Property by Seller to Buyer other than 
the fees due from Buyer to AMB Corporate Real Estate Advisors, Inc. ("AMB") 
under a separate agreement for services performed by AMB on Buyer's behalf. 
Buyer and Seller each shall indemnify, defend and hold the other harmless 
from and against any loss, cost or expense, including attorneys' fees and 
court costs, resulting from any claim for a commission or fee by any broker 
or finder, resulting from activities of the indemnifying party in connection 
with the execution of this Agreement or Buyer's purchase of the Property.

     16.  SUCCESSORS AND ASSIGNS.

          a.   GENERAL PROVISION. The terms, covenants and conditions herein 
contained shall be binding upon and inure to the benefit of the successors 
and assigns of the parties hereto.

          b.   ASSIGNMENT BY BUYER. Buyer shall have the right to assign its 
rights and obligations under this Agreement without the consent of Seller, 
except that Seller shall have the right to either consent to or reject an 
assignee that, in Seller's reasonable opinion, is not sufficiently 
financially capable to carry out the obligations of Buyer under this 
Agreement.

          c.   ASSIGNMENT BY SELLER.  Seller shall have the right, without 
Buyer's consent, to assign all his right, title and interest in the Property 
to a living trust which is under the sole control of Seller.

     17.  SURVIVAL. The terms, covenants and conditions herein contained 
required to be operative after delivery of the Deed or after termination or 
expiration of the Option, in order to be fully effective, shall be operative 
and shall not be deemed to have merged in the Deed or to terminate upon 
termination of this Agreement or the Option.

     18.  MEMORANDUM OF OPTION AGREEMENT.

          a.   RECORDATION.  Prior to delivery of the Option Payment, the 
parties shall cause to be recorded in the Official Records of Alameda County 
the Memorandum of Option Agreement, attached hereto as EXHIBIT E.

          b.   QUITCLAIM.  Buyer shall deliver to Title company a quitclaim 
deed concurrently with execution of this Agreement.  The quitclaim deed, 
which shall remove the Memorandum of Option Agreement from title to the 
Property, shall be held by


                                      9.

<PAGE>

Title Company for recordation if, for any reason, the option is not
exercised within the Option Term.

     19.  SPECIFIC PERFORMANCE. The parties hereby acknowledge that, in the 
event of a breach  or a threatened breach of any of the provisions of this 
Agreement by a party, damages are an inadequate remedy.  Accordingly, without 
limiting any other remedies of either party, the obligations of the parties 
under this Agreement may be enforced by specific performance.

     20.  ENTIRE AGREEMENT.  This Agreement contains all of the covenants, 
conditions and agreements between the parties regarding the Option and shall 
supersede all prior correspondence, agreements and understandings, both 
verbal and written, between the parties regarding the Option.  No addition or 
modification of any term or provision shall be effective unless set forth in 
writing and signed by both Seller and Buyer.

     21.  ASSURANCES FROM EXISTING LENDER.

          a.   NO RECOGNITION AGREEMENT INITIALLY.  Prior to execution of
this Agreement, it was not practical to obtain a recognition agreement for
this Agreement from Home Savings in connection with the Home Savings Deed
of Trust.  As a result, Seller and Buyer agree as follows:

               (i)   RIGHT TO CURE.  If Seller is in default of its 
obligations under the Home Savings Deed of Trust, Buyer shall have the right, 
but not the obligation, to cure the default and credit against the rent due 
under the Lease any amounts expanded by Buyer in connection with the cure 
(with any balance credited to the Purchase Price); and

               (ii)  PURCHASE AT FORECLOSURE.  If Home Savings (or its 
successor) begins a foreclosure action in connection with the Property, Buyer 
shall have the right to purchase the Property at the foreclosure sale so long 
as the foreclosure did not result either directly or indirectly from any 
act(s) of Buyer or its agents, assign(s), representative(s), related 
entity(ies), or those acting in concert with Buyer, whether by breach of any 
agreements between Buyer and Seller or otherwise, and otherwise subject to 
Seller's rights as set forth in Section 2l.b below.

          b.   RIGHT TO SEEK RECOGNITION AGREEMENT.  After this Agreement is 
executed by Buyer and Seller, Buyer shall have the right to seek a 
recognition agreement for this Agreement from Home Savings in connection with 
the Home Savings Deed of Trust. Actions by Buyer in seeking the recognition 
agreement shall not adversely impact Seller.  Buyer assumes and shall 
compensate Seller for any adverse impact on Seller as a result of Buyer 

                                      10.
<PAGE>

seeking a recognition agreement.  For purposes of this section 21.b,
adverse impacts include, but are not limited, to any charges imposed on
Seller which are over and above Seller's obligation to Home Savings, either
financially or temporally, or which result in a reduction in any manner of
Seller's interest in the Property, including, but not limited to,
foreclosure of Seller's interest in the Property, whether the Property is
purchased at any foreclosure by Buyer or others.

     22.  NO FURTHER ENCUMBRANCES. Seller shall not subject all or any 
portion of the Property  to any lien or encumbrance or otherwise revise the 
status of the title to the Property after the date of this Agreement; 
provided, however, that Seller may subject the Property to liens for monetary 
obligations to the extent that the credits to which Buyer is entitled (under 
Section 5(ii)) do not exceed eighty percent (80%) of the Purchase Price.

     23.  ATTORNEYS' FEES. In the event of any litigation regarding the 
rights and obligations  of the parties under this Agreement, the prevailing 
party shall be entitled to reasonable attorneys' fees and court costs.

     24. NOTICES. All notices or other communications required or permitted 
hereunder shall be in writing and delivered either by hand or deposited in 
the United States mail first-class, postage prepaid, and addressed to Buyer 
at Buyer's Address (as shown on Page i) or to Seller at Seller's Address (as 
shown on Page i), as applicable.  The foregoing addresses may be changed by 
written notice to the other party as provided in this Section.

     25.  LEASE.  Except as provided in this Agreement, the Lease shall 
remain in full force and effect and unamended.  In the event of conflict 
between the terms of this Agreement and the terms of the Lease, the terms of 
the Lease shall control.

     26.  EXHIBITS. Exhibits A, B, C, D and E are attached hereto and 
incorporated herein by reference thereto.

     27.  GOVERNING LAW. This Agreement shall be governed by and construed in 
accordance with the laws of the State of California.

     28.  CONFIDENTIALITY.  Seller and Buyer agree to keep confidential, and 
not publicly disclose, the terms of this Agreement and the transaction 
contemplated hereby.  However, both Buyer and Seller may disclose the terms 
of this Agreement to: (i) their respective lenders, consultants, agents, 
architects, independent contractors, attorneys or surveyors associated with 
the purchase and sale of the Property; (ii) any governmental

                                      11.
<PAGE>

authority to which such disclosure is required by law; or (iii) any third
party to whom the non-disclosing party to this Agreement has given its
prior written consent for such a disclosure.

     29.  TIME. Time is of the essence of every provision herein contained.

     IN WITNESS WHEREOF, the parties hereto have executed one (1) or more
copies of this Agreement, on the date(s) set forth below, as of the day and
year first above written.

                                       "Seller"
                                       /s/ H.B. Chapman Jr.
                                       ------------------------------
                                       HAROLD B. CHAPMAN, JR.
                                       an individual
                                       Date: June 7, 1995
                                             ------------------------

                                       "Buyer"

                                       CHIRON CORPORATION,
                                       a Delaware corporation


                                       By: /s/ Dennis L. Winger
                                           --------------------------
                                       Name: Dennis L.  Winger
                                            -------------------------
                                       Its: Vice President
                                            -------------------------
                                       Date: June 7, 1995
                                            -------------------------


                                       12.
<PAGE>


                                EXHIBIT A
                               ----------



                          PROPERTY DESCRIPTION


CITY OF EMERYVILLE

PARCEL "B", PARCEL MAP NO. 2108, FILED JUNE 17, 1977, IN MAP BOOK
97, PAGE 40, ALAMEDA COUNTY RECORDS.

ASSESSOR'S PARCEL NO. 049-1041-049



<PAGE>
                                EXHIBIT B
                               ----------

                                  LEASE


     THIS LEASE AGREEMENT is made as of this 1st day of July, 1983, between
H. B. CHAPMAN, JR. ("Chapman"), an individual, and CETUS CORPORATION, a
Delaware corporation ("Cetus").

     In consideration of their mutual promises herein, the parties agree as
follows;

     LEASED PREMISES

     1.1  DEFINITION OF PREMISES.  Chapman hereby leases to Cetus, and
Cetus hereby hires from Chapman, for the term and subject to the provisions
of this Agreement that certain real property (the "Premises") commonly
known as 1400 and 1450 53rd Street, Emeryville, California and more
particularly described by metes and bounds on Exhibit A hereto and depicted
on the size plan attached as Exhibit A-1 hereto.  The Premises include the
land described on Exhibit A, all appurtenances thereto and all improvements
thereon, including without limitation two buildings (the "Buildings")
described as Building M and Building G on Exhibit A-1, a parking lot, a
loading dock, driveway access to the loading dock, driveway access to the
parking lot, a bridgeway connection between the Buildings and the property
owned by Cetus at 4560 Horton Street, Emeryville, California, exterior
walkways, stairways and other facilities exterior to the Buildings.  Cetus
acknowledges and agrees that it receives the Premises in "as is" physical
condition.

<PAGE>

     1.2  LESSOR'S TITLE.  Chapman warrants that he has fee simple title to
the real property described on Exhibit A and Exhibit A-1, the improvements
thereon and the appurtenances thereto.  Chapman shall vacate Area 1 of
Building G, as marked in blue on Exhibit A-1, by August 1, 1983.  Chapman
shall vacate Area 2 of Building G, as marked in red on Exhibit A-1, by
September 1, 1983.  Chapman shall vacate Area 3 of Building G, as marked in
yellow on Exhibit A-1, and shall cause the existing tenant of Area 3 to
vacate the Premises, by October 1, 1983.  Chapman shall secure to Cetus the
quiet, peaceful and undisturbed possession of the Premises during the term
of this Lease against any persons who claim any title to or interest in the
Premises; provided, however, that Cetus acknowledges the rights of the
existing tenants of Building M and the existing tenant of Area 3 of
Building G pursuant to the leases (the "Prior Leases") described on Exhibit
B hereto; provided further however that as of the date hereof Chapman
hereby (a) represents and warrants that no default exists under any of the
Prior Leases, (b) assigns to Cetus all of his right, title and interest
pursuant to the Prior Leases including all right to modify or extend the
Prior Leases, (c) delivers to Cetus subordination and attornment agreements
in favor of Cetus from each of the tenants ("Prior Tenants") under the
Prior Leases, and (d) confirms that upon expiration or earlier termination
of 


                                     -2-

<PAGE>

any Prior Lease, Cetus shall have without exception the quiet, peaceful,
undisturbed possession of that portion of the Premises covered by the Prior
Lease.

     1.3  HORTON STREET.  The term "Horton Street" refers to the paved
automobile access route (I.E., paved road) on the immediate west side of
Building G. So long as Cetus retains control of Horton Street it agrees to
maintain it at its own expense.

     TERM

     2.1  TERM AND OPTIONS TO RENEW.

     The term of this Lease shall be 7 years from July 1, 1983 (the
"Commencement Date").  Cetus shall, however, have the option to extend this
Lease and all of its other provisions for 7 additional 2-year terms. The
exercise of each of these 2 year options shall be automatic unless Cetus
gives at least 60 days notice of its intent not to exercise each such
option.  However, if not more than 70 days prior to the expiration of the
then current term Chapman delivers to Cetus written notice that Chapman
seeks notification as to whether Cetus is exercising its option to extend,
then Cetus must deliver to Chapman within 10 days after Cetus receives such
notice from Chapman Cetus' written notification as to whether Cetus is
exercising its option to extend. If Cetus does not deliver the notices
required of it pursuant to this Section 2.1, then Chapman shall be under no
obligation to further extend the Lease.


                                     -3-

<PAGE>

     RENT

     3.1  RENT.  Rent for the premises shall be $57,362.50 per month.

     3.2  PERIODIC PAYMENTS OF RENT.  The rent shall be paid in equal
monthly installments due on the first day of each month; except, however,
that on or before July 1, 1983 Cetus shall pay Chapman the monthly rent for
the month of July 1983 and for the month of June 1984.  Cetus' prepayment
of the rent for the month of June 1984 shall be the only advance rental
payment required under this Lease. If this Lease terminates on a day other
than the last day of a calendar month, the monthly rental for the last
fractional month shall be prorated.

     3.3  MANNER OF PAYMENT.  Rental shall be paid to Chapman in lawful
money of the United States of America at the address set forth herein for
delivery of notices to Chapman or to such other person or at such other
place as Chapman may from time to time designate in writing.

     3.4  PRIOR LEASES.  The parties acknowledge that pursuant to the Prior
Leases portions of the Premises are currently rented out to various other
tenants.  Cetus acknowledges and agrees that in leasing the Premises from
Chapman it takes "subject to" the Prior Leases.  Cetus understands and
accepts that Chapman makes no guarantees as to the validity or terms of the
Prior Leases.  However, along with the right to occupy the Premises, Cetus
by execution of this Lease gains the right to sublease space in the
Premises to new


                                     -4-

<PAGE>

tenants and collect rents from existing tenants and to negotiate new rental
terms with Cetus' subtenants or the said existing tenants.  By executing
this Lease Cetus also agrees that it relieves Chapman of the responsibility
of removing existing tenants for violation of provisions of their rental
agreements occurring from and after the Commencement Date and agrees to
waive any claims against Chapman for any breaches of the Prior Leases
occurring after the Commencement Date.  Cetus also agrees that it waives
any claims against Chapman for any damage Cetus may have sustained or may
in the future sustain as a result of Chapman's failure to evict Roger
Schmidt.

     TAXES

     4.1  TAXES.  The parties agree that the real property tax obligation
on the Premises which accrues during the term of this Lease shall be paid
by Cetus.

     UTILITIES

     5.1  UTILITIES. Immediately upon the Commencement Date Cetus shall
become solely responsible for payment of all utilities supplied to the
Premises including, but not limited to, gas, electricity and water and
shall immediately notify said utility suppliers.  Cetus may thereafter
charge each other tenant on the Premises its prorated share of the cost of
each said utility.

     5.2  METERING.  Cetus may at its own expense install any utility
metering system it desires.


                                     -5-


<PAGE>

     USE

     6.1  PERMITTED USE.  Cetus may use the Premises for all purposes
consistent with the current zoning laws to which the Premises are subject.

     6.2  SAFETY.  Should Cetus cease its use of the Premises while Chapman
remains owner of the Premises, Cetus agrees to leave the Premises in a
condition which is safe and nonhazardous to human and other forms of life. 
Cetus agrees that if after it has so left the Premises an unsafe condition
caused and left by Cetus is responsible for injury to any individual, Cetus
will hold Chapman harmless and indemnify him for any and all costs or
compensation reasonably paid by Chapman as a result of such injury.  Cetus
also agrees to fully reimburse Chapman for any expenditures reasonably made
by Chapman for the purpose of making the Premises safe after Cetus has left
the Premises.  The covenants contained in this Section 6.2 are personal to
Chapman and are not transferable to his successors and assigns and further
shall expire on the second anniversary of the date Cetus ceases to use the
Premises.

     BUILDING SERVICES

     7.1  PROVISIONS BY CETUS.  Cetus, at Cetus' expense, shall furnish the
Premises with such (i) elevator service, (ii) lighting replacement (for
building standard lights) in common areas, (iii) restroom supplies in
common areas, and (iv) janitor service in common areas as Cetus may require
or as is required pursuant to the Prior Leases.


                                     -6-

<PAGE>

     SECURITY

     7.2  SECURITY.  Throughout the term hereof Cetus shall provide for
the security of the Premises, including the breezeway, as it sees fit, and
may, at Cetus' expense, implement an increased security system.

     7.3  LOADING DOCK-BREEZEWAY DOOR.  Cetus shall be responsible for the
security of the door between the loading dock and the breezeway, which is
located at the north end of the breezeway.

     MAINTENANCE; REPAIRS

     8.1  CETUS' OBLIGATIONS.  Cetus, at Cetus' expense, shall at all times
during the term hereof maintain all public and common areas (including
lobbies, stairs, elevators, corridors and restrooms), windows, doors, the
breezeway, the mechanical, plumbing and electrical equipment, the parking
area, and foundations, exterior walls and roof, of the Premises all as
Cetus may require or as may be required of the landlord pursuant to terms
of the Prior Leases.

     8.2  CETUS' GENERAL OBLIGATIONS.  Cetus shall, at all times during the
terms hereof and at Cetus' sole cost and expense, keep the Premises in good
order, condition and repair, excepting only that portion of the Premises
for which tenants under Prior Leases are responsible and ordinary wear and
tear and damage to the Premises by fire, earthquake, the elements or other
causes beyond Cetus' reasonable control.


                                     -7-

<PAGE>

     8.3  CETUS' RIGHTS WITH RESPECT TO HVAC.  Cetus shall maintain (at
Cetus' expense) the heating, ventilating and air conditioning systems in
the Buildings as Cetus may require or as may be required of the landlord
pursuant to the terms of the Prior Leases.  Cetus may, at Cetus' expense,
put into working order, operate and maintain exhaust fans and exhaust
systems on the Premises.

     8.4  HEAT.  Cetus shall be responsible for providing an operating
boiler system at the Commencement Date for Cetus' and other tenants' use. 
Cetus, at Cetus' expense, shall maintain the boiler system during the term
of this Lease and furnish the fuel therefor.

     ALTERATIONS

     9.1  ALTERATIONS.  Cetus may, at Cetus' expense, make any structural
or nonstructural alterations, additions or improvements in, on or to any
space in the Premises as Cetus desires as long as the present value of the
Premises is not diminished and all such changes conform to the requirements
of and receive the approval of all relevant government agencies including
those of the City of Emeryville, County of Alameda, State of California,
and the United States of America.  If and only if Cetus intends to make
alterations which materially affect the structure or exterior face of the
Buildings, Cetus shall within 10 days prior to actually commencing work on
said alterations provide to Chapman copies of all plans, prints,
blueprints, details, working drawings and all other relevant


                                     -8-

<PAGE>

construction documents and shall also provide an adequate work space on the
Premises for Chapman to review the said documents.  Cetus shall not have
the right to actually commence physical work on alterations which
materially affect the structure or exterior face of the Buildings without
the prior written approval of Chapman; provided however that Chapman shall
not unreasonably withhold prior written approval, and if Chapman has not
approved or disapproved of the alterations within 10 days of submission of
the material plans and specifications therefor, he shall be deemed to have
granted prior written approval.

     9.2  MECHANICS' LIENS.  Cetus shall keep the Premises free from any
liens arising out of any work which it causes to be performed for materials
furnished to or obligations incurred by Cetus.  Each party shall have the
right to post and keep posted on the Premises any notices that may be
provided by law or which either party may deem to be proper for the
protection of the Premises against such liens. If within 10 days following
the imposition of any lien the obligated party has not caused the lien to
be released of record by payment or by posting of a proper bond, the other
party, in addition to all other remedies provided in this Lease and by law,
shall have the right, but shall not be obligated, to cause the lien to be
released by such means as it deems proper, including payment of the claim
giving rise to the lien.  All payments made and expenses incurred by that
party in connection with the lien shall be reimbursed to that party.


                                     -9-

<PAGE>

     INSURANCE

     10.1 PROPERTY INSURANCE.  Cetus at its own expense shall carry
throughout the term hereof property insurance on the Premises in the amount
of the fair market value of the Buildings and improvements
("Improvements").  The fair market value of the Improvements shall be
redetermined at least once every two years in a manner reasonably
acceptable to both parties and to Cetus' insurance carrier by an
independent appraiser.  Such appraisal shall delineate the amount of
coverage for (a) the exterior walls and the roof of each of the two
Buildings, the on-site improvements and other improvements made to the
Premises by Chapman or his predecessors in interest at his or their
expense, and (b) the leasehold improvements previously or hereafter made to
the Premises by Cetus at its expense and Cetus' fixtures and personality. 
The insurance shall name H. B. Chapman, Jr. as an additional insured.  Such
insurance shall contain coverage against loss or damage by fire and such
other risks as are now or hereafter included under "All Risks" coverage in
common use for commercial structures in the vicinity of the Premises.  Said
coverage may provide for a deductible amount of up to $15,000; Cetus shall
not accept a greater deductible amount without first obtaining Chapman's
prior written consent, which Chapman shall not unreasonably withhold, and
Chapman's consent shall be presumed if Chapman does not object to a
proposed greater deductible within 20 days after notice thereof from Cetus.


                                     -10-


<PAGE>

     10.2 LIABILITY INSURANCE.  Cetus, at its own expense, shall carry
throughout the term hereof comprehensive general liability insurance to
protect against liability to the public incident to or resulting from any
accident on the Premises.  The coverage of such insurance shall be not less
than $1,000,000 for any one person injured, $3,000,000 for any one accident
and $1,000,000 for property damage.  By endorsement Cetus shall include
contractual obligation protection under said liability coverage. In any
policy of liability insurance purchased by either party to this Lease the
other party shall be named as a co-insured.

     10.3.     CHAPMAN'S SEPARATE COVERAGE.  Chapman, at his expense, may
also place any other or additional insurance coverage he desires, which
shall be in Chapman's name and in which Cetus shall have no interest.

     10.4 BOILER AND MACHINERY INSURANCE.  Cetus at its cost shall maintain
boiler and machinery insurance on all boilers, heating and air conditioning
equipment and other standard equipment in, on or about the Buildings
routinely covered by such insurance, if any of these items and the damage
that may be caused by them are not covered by the "All Risk" insurance
referred to in Section 10.1. The boiler and machinery insurance shall have
limits of not less than $100,000 per occurrence.


                                     -11-

<PAGE>

     10.5 SUBROGATION.  Each party shall cause each insurance policy obtained 
by it and relating to the Premises to provide that the insurance company 
waives all right of recovery by way of subrogation against the other in 
connection with any damage covered by any policy.

     10.6 FORM OF POLICIES. The policies evidencing the coverage carried by a 
party under this Article 10 shall be issued by insurance companies licensed 
to do business in the State of California and provide that (a) the coverage 
is primary and noncontributing to any insurance that may be carried by the 
other party; (b) the coverage cannot be cancelled, modified, reduced or 
otherwise materially changed except after 30 days prior written notice to the 
other party; and (c) the other party shall be included as an additional 
insured.

     10.7 PROCEDURES AND REMEDIES.  The party hereto responsible for carrying
insurance under this Article 10 shall deliver to the other party, in the
manner required for notices, (a) certificates or binders evidencing all
insurance policies and endorsements this Lease requires the party to carry,
and (b) proof satisfactory to the other party that the premiums for the
procurement and maintenance of such coverage are fully paid, all within the
following time limits:

          (i)  for insurance required at the commencement of the term of this 
Lease within 60 days from the Commencement Date; and


                                     -12-

<PAGE>

          (ii) for any renewal or replacement of a policy already in 
existence, at least 30 days before expiration or other termination of the 
existing policy.

     If a party fails or refuses to procure or to maintain the insurance
coverage required hereunder or fails or refuses to furnish the other party
with proof that said coverage has been procured and is in force and paid
for, the other party shall have the right, without notice, but without any
obligation so to do, to procure and maintain such coverage.  The defaulting
party shall reimburse the curing party on demand for any premiums the
latter so pays.

     COMPLIANCE WITH LAW

     11.1 COMPLIANCE WITH LAW.  Cetus shall at its sole cost and expense 
promptly comply with all laws, statutes, ordinances and governmental rules, 
regulations or requirements now in force or which may hereafter be in force, 
with the requirements of any board of fire underwriters or other similar body 
now or hereafter constituted, with any direction or occupancy certificate 
issued pursuant to any law by any public officer or officers, as well as the 
provisions of all recorded documents affecting the Premises, insofar as they 
relate to the condition, use or occupancy of the Premises, excluding 
requirements of code compliance and or structural changes not related to 
Cetus' acts.


                                     -13-

<PAGE>

     ASSIGNMENT AND SUBLETTING

     12.1 USE CONSISTENT WITH ZONING.  While Cetus may assign or sublease its
interest under the Lease, any such assignment or sublease shall be invalid
and shall constitute a breach of the Lease if the assignee or sublessee
uses the assigned or subleased premises in a manner which is inconsistent
with the then current zoning laws to which the Premises are subject.  Any
transfer of this Lease by operation of law, whether resulting from death,
merger, consolidation or liquidation, shall constitute an assignment for
purposes of this Section.

     12.2 SUBLETTING: NOTICE TO CHAPMAN.  If at any time or from time to time 
during the term of this Lease Cetus desires to sublet all or any part of the 
Premises, Cetus shall give notice to Chapman setting forth the terms of the 
proposed subletting and the space so proposed to be sublet.  No sublease 
shall be valid and no sublessee shall take possession of the Premises 
subleased until an executed counterpart of such sublease has been delivered to
Chapman.

     12.3 CHAPMAN'S RIGHT TO ENCUMBER.  At any time during the term of this 
Lease, Chapman, with Cetus' prior written consent and subject to Cetus' 
rights under this Lease, may encumber the Premises with a deed of trust or 
mortgage to secure a loan to Chapman.  If Chapman exercises his right to 
encumber the Premises in accordance with this Section 12.3, Cetus agrees to 
subordinate to second position the Chapman Note (as defined


                                     -14-

<PAGE>

below) and the deed of trust securing the Chapman Note to the new
encumbrance, pursuant to such subordination documentation as may be
reasonably acceptable to Cetus; provided, however, that if the prior
encumbrance is foreclosed or enforced, this Lease shall not be terminated
nor any of Cetus' rights hereunder disturbed, including without limitation
Cetus' rights to offset its payment obligations hereunder by the amount of
any delinquent payments under the Chapman Note.

     ENTRY BY CHAPMAN

     13.1 ENTRY BY CHAPMAN. Chapman may upon 48 hours prior written notice
enter the Premises at reasonable hours to (a) inspect the same, (b) exhibit 
the same to prospective lenders, (c) determine whether Cetus is complying 
with all its obligations hereunder, and (d) post notices of 
nonresponsibility. Chapman shall further have the right, without notice to 
Cetus, of ingress and egress over the easement (the "Dock Easement") depicted 
in green and labeled Dock Easement on Exhibit A-1 hereto; provided, however, 
that Chapman shall exercise such easement rights in a manner as will not 
interfere with Cetus' use of the Dock Easement or the remainder of the 
Premises.


                                     -15-

<PAGE>

     DEFAULT

     14.1 CHAPMAN'S NOTE.  Attached hereto as Exhibit C is a copy of Chapman's
promissory note ("Chapman's Note") dated December 5, 1980 in favor of Cetus
in the principal amount of $500,000.00. As of the Commencement Date
Chapman's Note has an outstanding principal balance of $447,788; interest
resuming on July 1, 1983.  Cetus' payment obligations hereunder are
conditioned upon the payment by Chapman to Cetus of each installment under
the Chapman Note on or before its due date, and Cetus shall have the right
to offset against payments otherwise due hereunder the amount of any
delinquent payment of principal and/or interest under the Chapman Note.

     14.2 EVENTS OF DEFAULT.  The occurrence of any one or more of the following
events ("events of default") shall constitute a substantial breach of this
Lease by Cetus:

          a.   FAILURE TO PAY RENT.  Cetus fails to pay any rental in full 
when the same becomes due, if such failure is not due to Cetus' exercise of 
its offset rights pursuant to Section 14.1 above and if such failure 
continues for more than 10 days after Cetus' receipt from Chapman of notice 
of the amount due; or

          b.   FAILURE TO PAY OTHER SUM.  Cetus fails to pay any other sum 
when the same becomes due, if such failure is not due to Cetus' exercise of 
its offset rights pursuant to


                                     -16-



<PAGE>


Section 14.1 above and if such failure continues for more than 10 days
after Cetus' receipt from Chapman of notice of the amount due; or

          c.   FAILURE TO PERFORM.  Cetus fails to perform or observe any of 
Cetus' other obligations under this Lease, if such failure continues for more 
than 30 days after notice from Chapman or from any governmental body with 
jurisdiction over the Premises describing the delinquent obligation; 
provided, however, that if by its nature the breach cannot be cured within 30 
days but Cetus nevertheless has the capacity to cure the breach, Cetus may 
have such longer period as is necessary upon the condition that Cetus 
promptly commences the curing of the breach within the 30-day period and 
thereafter diligently pursues the cure to completion; or

          d.   BANKRUPTCY.  Cetus makes a general assignment for the benefit 
of creditors, or admits in writing its inability to pay its debts as they 
become due or files a petition in bankruptcy, or is adjudicated as bankrupt 
or insolvent or files a petition in any proceeding seeking any 
reorganization, arrangement, composition, readjustment, liquidation, 
dissolution or similar relief under any present or future statute, law or 
regulation, or files an answer admitting, or fails timely to contest, the 
material allegations of a petition filed against it in any such proceeding, 
or seeks or

                                  -17-

<PAGE>

consents to or acquiesces in the appointment of any trustee, receiver or
liquidator of Cetus or any material part of its properties; or

          e.   REORGANIZATION.  Any proceeding against Cetus seeking any 
reorganization, arrangement, composition, readjustment, liquidation, 
dissolution or similar relief under any present or future statute, law or 
regulation is not dismissed within 90 days after the commencement thereof, an 
appointment is made without the consent or acquiescence of Cetus of a 
trustee, receiver or liquidator of Cetus or of any material part of its 
properties which is not vacated within 90 days thereafter; or

          f.   LEVY.  This Lease or any estate of Cetus hereunder is levied 
upon under any attachment or execution and such attachment on execution is 
not vacated within 30 days thereafter.

     14.2 CHAPMAN'S REMEDIES UPON AN EVENT OF DEFAULT

          a.   TERMINATION.  If an event of default occurs, Chapman may give 
a written termination notice to Cetus, and on the date specified in the 
notice (which shall not be less than three days after the giving of such 
notice) this Lease shall terminate, unless on or before such date all arrears 
of rental and all other sums payable by Cetus under this Lease and all costs 
and expenses incurred by or on behalf of Chapman have been paid by Cetus at 
the time existing have been fully remedied to the reasonable satisfaction of 
Chapman.

                                       -18-

<PAGE>

          b.   CONTINUATION OF LEASE, Even though Cetus has breached this 
Lease or abandoned the Premises, this Lease shall continue in effect for so 
long as Chapman does not terminate this Lease, and Chapman may enforce all 
rights and remedies including the right to recover the rental as it becomes 
due.  Acts of maintenance or preservation of or efforts to relet the Premises 
or the appointment of a receiver upon initiative of Chapman to protect 
Chapman's interest under this Lease shall not constitute a termination of 
this Lease.

         c.   OTHER RELIEF.  The remedies provided for in this Lease are in 
addition to any other remedies available to Chapman at law or in equity by 
statute.

     ATTORNEYS' FEES

     15.1 ATTORNEYS' FEES in the event of any action or proceeding brought by 
either party against the other under this Lease, the prevailing party shall 
be entitled to recover reasonable attorneys' fees.

     DAMAGE OR DESTRUCTION

     16.1 CETUS' OBLIGATION TO RESTORE.  If there is damage to the Premises 
caused by fire or any casualty which is covered by the policy of fire and All 
Risks coverage insurance described in Section 10.1 above, and if the proceeds 
to Cetus therefrom are sufficient to cover the full cost of the restoration, 
Cetus shall forthwith repair the damage, subject to the provisions of 
Sections 16.3 and 16.4 below, and this Lease shall remain in

                                  -19-


<PAGE>

full force and effect.  Rental hereunder shall abate while the repair work is 
underway in proportion to the degree to which the Premises are rendered 
unusable.

     16.2 CETUS' OPTION TO RESTORE.  If the damage results from a casualty 
not covered by fire or All Risks coverage insurance or if the proceeds to 
Cetus from such insurance are insufficient to cover the full cost of the 
restoration, then Cetus may, at its option, upon written notice to Chapman, 
within 30 days after the date of such fire or other casualty, restore the 
damage, and this Lease shall remain in full force and effect, subject to the 
abatement provision set forth in Section 16.1 above.

     16.3 OPTION TO TERMINATE.  If (a) Cetus does not elect to make repairs 
pursuant to Section 16.2 above, or (b) either 20% of the floor area of the 
Buildings or 20% of the parking lot area or such portion of the Premises as 
otherwise interferes with Cetus' operations on the premises are damaged or 
destroyed, or (c) the damage occurs during the last 9 months of the term of 
this Lease, then Cetus may by written notice to Chapman, given within 30 days 
after the date of the fire or other casualty, terminate this Lease as of the 
date of the fire or other casualty; provided, however, that if Chapman 
promptly makes available to Cetus alternate parking facilities which are 
reasonably acceptable to Cetus with respect to quality, area and location, 
then Cetus shall not terminate this Lease if the sole grounds for termination 
would have been the destruction of 20%

                                  -20-


<PAGE>

or more of the parking lot area.  If Cetus elects to terminate under this 
paragraph, then Chapman shall be entitled to receive a portion of the 
insurance proceeds proportional to the fair market value of the Buildings as 
set forth in the fair market value appraisal of the Improvements (Section 
10.1).

     16.4 TOTAL DESTRUCTION.  A total destruction of the Premises shall 
automatically terminate this Lease.

     EMINENT DOMAIN

     17.1 CONDEMNATION. If all or any part of the Premises are taken by 
eminent domain, this Lease shall terminate as to the part so taken as of the 
date of the taking.  In the case of partial taking which exceeds 20% of the 
floor area of the Buildings or 20% of the parking lot area or otherwise 
materially interferes with Cetus' operations on the Premises, Cetus shall 
have the right to terminate this Lease; provided, however, that if Chapman 
promptly makes available to Cetus alternate parking facilities which are 
reasonably acceptable to Cetus with respect to quality, area and location, 
then Cetus shall not terminate this Lease if the sole grounds for termination 
would have been the taking of 20% or more of the parking lot area.

     17.2 AWARD TO CETUS.  If all or any part of the Premises is taken by 
eminent domain Cetus shall be entitled to any and all compensation, damages, 
income, rents, awards, on any interest whatsoever which may be paid or made 
in connection with the value of Cetus' leasehold or purchase interest, its 
lease-

                                  -21-

<PAGE>

hold improvements and fixtures, or with loss of or damage to Cetus' personal 
property on the Premises or with moving expenses and other severance damages.

     17.2 REDUCTION OF RENTAL.  In the event of a partial taking of the 
Premises which does not result in a termination of this Lease, the monthly 
rental thereafter to be paid shall be reduced in proportion to the value of 
the Premises taken.

     SURRENDER

     18.1 SURRENDER OF LEASE NOT MERGER.  The voluntary or other surrender of 
this Lease by Cetus, or a mutual cancellation thereof, shall not work a 
merger, and shall at the option of Chapman, terminate all or any existing 
subleases or subtenancies, or may, at the option of Chapman, operate as an 
assignment to Chapman of any or all such subleases or subtenancies.

     18.2 REDELIVERY OF PREMISES TO LESSOR. Upon termination of this Lease 
for any reason other than acquisition of title to the Premises by Cetus, 
Cetus shall surrender the Premises to Chapman in good order, condition and 
repair, excepting only ordinary wear and tear, damage occasioned by the act 
or omission of Chapman and damage thereto by fire, earthquake, the elements 
or causes beyond Cetus' reasonable control.

                                  -22-

<PAGE>

     HOLDING OVER

     19.1 HOLDING OVER.  If, without objection by Chapman, Cetus holds 
possession of the Premises after expiration of the term of this Lease, Cetus 
shall become a tenant from month to month upon the same terms herein 
specified.  Each party shall give the other written notice at least one month 
prior to the date of termination of such monthly tenancy of its intention to 
terminate such tenancy.

     SIGNS

     20.1 SIGNS.  Chapman shall permit Cetus to have sign identification on 
and within the Buildings which is compatible with the aesthetics thereof.

     BROKERS AND FINDERS

     21.  BROKERS AND FINDERS.  Each party represents that it has not had 
dealings with any real estate broker, finder, or other person with respect to 
this Lease.  Each party shall hold harmless the other party from all damages 
resulting from any claims that may be asserted against the other party by any 
broker, finder or other person, with whom the party has or had purportedly 
dealt.

     MISCELLANEOUS

     22.1 WAIVER.  The waiver by a party of any agreement, condition or 
provision herein contained shall not be deemed to be a waiver of any 
subsequent breach of the same or any other agreement, condition or provision, 
nor shall any custom or practice which may grow up between the parties in the

                                  -23-

<PAGE>

administration of the terms hereof be construed to waive or to lessen the 
rights of a party to insist upon the performance by the other party in strict 
accordance with the terms of this Lease.

     22.2 NOTICES.  All notices and demands which may or are required to be 
given by either party to the other hereunder shall be in writing and shall be 
deemed to have been fully given when personally served (but upon an officer 
of Cetus in the case of Cetus) or when deposited in the United States mail, 
certified or registered, postage prepaid, and addressed as follows:

          To Chapman at 1450 - 53rd Street
               Emeryville, California 94608

          To Cetus at 1400 53rd Street
               Emeryville, California 94608

or such other place as a party may designate by notice to the other.

     22.3 COMPLETE AGREEMENT.  There are no oral agreements between Chapman 
and Cetus affecting this Lease, and this Lease supersedes and cancels any and 
all previous negotiations, arrangements, agreements and understandings, if 
any, between Chapman and Cetus pertaining to the subject matter of this Lease 
or the Buildings; provided, however, that until such time as Chapman's 
covenants pursuant to Section 1.2 hereof are satisfied, then Cetus' rights 
pursuant to that certain Optional Exchange Agreement, between Cetus and 
Chapman, dated January 1,

                                  -24-

<PAGE>

1982, shall survive.  There are no representations, warranties or 
inducements, express or implied, between Chapman and Cetus, except as stated 
in this Lease.

     22.4 CORPORATE AUTHORITY.  If Cetus signs as a corporation, each of the 
persons executing this Lease on behalf of Cetus does hereby covenant and 
warrant that Cetus is a duly authorized and existing corporation, that Cetus 
does and is qualified to do business in California, that the corporation has 
full right and authority to enter into this Lease, and that each of the 
persons signing on behalf of the corporation is authorized to do so.

     22.5 TIME IS OF THE ESSENCE.  Time is of the essence of this Lease and 
each and all of its provisions.

     22.6 HEIRS, ETC., BOUND BY AGREEMENT.  Except as provided in Section 6.2 
above, the agreements, conditions and provisions herein contained shall, 
subject to the provisions as to assignment, apply to and bind the heirs, 
executors, administrators, successors and assigns of the parties hereto.

     22.7 SEVERABILITY.  If any provision of this Lease in determined to be 
illegal or unenforceable, such determination shall not affect any other 
provision of this Lease and all such other provisions shall remain in full 
force and effect.

     22.8 GOVERNING LAW.  This Lease shall be governed by and construed 
pursuant to the laws of the State of California.

                                  -25-

<PAGE>

     22.9 CAPTIONS.  The captions in this Lease are for convenience only, are 
not a part of this Lease and do not in any way limit or amplify the 
provisions hereof.

     22.10     MEMORANDUM.  Upon the request of a party, Chapman and Cetus 
shall execute in recordable form a Memorandum of this Lease, which the 
requesting party may record.

     22.11     FURTHER INSTRUMENTS.  From time to time prior to and after the 
execution of this Lease, each party shall execute and deliver such 
instruments and other documents as may be reasonably requested by the other 
party or necessary to carry out the purposes and intent of this Lease.  

       EXHIBITS, ADDENDA

     23.1 EXHIBITS, ADDENDA.  The exhibits hereto and addenda, if any, are 
made a part of this Lease.

Dated:   June 23, 1983               \s\ Harold B. Chapman, Jr.
                                     ------------------------------
                                     HAROLD  B. CHAPMAN, JR.


Dated: June 23, 1983                 CETUS CORPORATION
                                      By: /s/ Signature Unreadable
                                          -------------------------
                                      Title: Vice President and 
                                             General Counsel
                                             ----------------------



                                  -26-


<PAGE>

                                EXHIBIT A

BASIS OF BEARINGS

The northerly line of 53rd St. at Horton St. Taken as S72 degrees 28'W.

LEGAL DESCRIPTION

     That parcel of land in the city of Emeryville, County of Alameda, State of
California, described as follows:

Parcel "B" of Parcel map No. 2108, filed June 17, 1977, map book 97, pages
40 and 41, Alameda County records, more particularly described as follows:

Beginning at the intersection of the north line of 53rd St. and the east
line of Horton Street thence following said east line of Horton Street
north 17 degrees 32' west 299.19 feet; thence leaving said east line of
Horton Street north 72 degrees 28' east 100.17 feet; thence north 17
degrees 32' west 43.00 feet; thence north 72 degrees 28' east 42.83 feet;
thence north 17 degrees 32' west 43.00 feet; thence north 72 degrees 28'
east 131.59 feet; thence south 17 degrees 32' east 385.19 feet to said
north line of 53rd Street; thence following said line south 72 degrees 18'
west 274.59 feet to the point of beginning.


<PAGE>

                           AMENDMENT TO LEASE

     This AMENDMENT TO LEASE (the "Amendment") is made as of this 20th day of
March 1990, between Harold B. Chapman, Jr., an unmarried man ("Chapman"),
and Cetus Corporation, a Delaware corporation ("Cetus") (collectively the
"parties").

                                RECITALS

     A.   Chapman is the lessor and Cetus is the lessee under that
certain Lease, dated July 1, 1983 (the "Lease"), between Cetus and Chapman
concerning the premises commonly known as M&G Buildings, located at 1400
and 1450 53rd Street, Emeryville, California.  Terms defined in the Lease
shall have the same meaning when used in this Amendment.

     B.   Pursuant to that certain Settlement Agreement and Release, of even 
date herewith, the parties agree to amend the Lease as provided herein.

                                AGREEMENT

     NOW, THEREFORE, in consideration of the premises and other valuable
consideration, the receipt and adequacy of which are hereby acknowledged,
the parties hereby agree as follows:

     1.   Paragraph 2.1 of the Lease entitled "TERM AND OPTIONS TO RENEW" is 
amended in its entirety to read as follows:

         2.1  TERM AND OPTIONS TO RENEW.  The term of this lease shall be 7
         years from July l, 1983 (the "Commencement Date"). Cetus shall, 
         however, have the option to extend this lease and all of its other 
         provisions for nine


<PAGE>

         additional 2-year terms.  The exercise of each of these 2-year options
         shall be automatic unless Cetus gives at least 60 days notice of its 
         intent not to exercise each such option.  However, if not more than 
         70 days prior to the expiration of the then current term Chapman 
         delivers to Cetus written notice that Chapman seeks notification as to
         whether Cetus is exercising its option to extend, then Cetus must 
         deliver to Chapman within 10 days after Cetus receives such notice
         from Chapman, Cetus' written notification as to whether Cetus
         is exercising its option to extend. If Cetus does not deliver the 
         notices required of it pursuant to the preceding sentence, then 
         Chapman shall be under no obligation to further extend the lease.

          2.   Paragraph 3.1 of the Lease entitled "RENT" is amended in its 
entirety to read as follows:

         3.1  RENT.  Rent for the premises shall be $57,362.50 per month. 
         Effective July 1, 1990, and each July 1st thereafter during the term 
         of the Lease, up to and including July 2003, the monthly rent for that
         July and the succeeding 11 months for the premises as set forth in the
         first sentence of this paragraph shall be two


                                     -2-

<PAGE>

         and one-half percent (2-1/2%) greater than the monthly rent payable 
         for the preceding 12 months.  Effective July 1 of each lease year 
         beginning July 1, 2004 and each July 1st thereafter, the monthly rent
         for that July and the succeeding 11 months shall increase from the 
         rent payable for the preceding 12 months by a percentage equal to the 
         net percentage of any increase by which the Consumer Price Index For 
         All Urban Consumers (1982-84 = 100) of the San Francisco-Oakland 
         Metropolitan Area, All Items,published by the Bureau of Labor 
         Statistics of the United States Department of Labor (the "Index"), as 
         of September of the prior year, has increased over the Index for the 
         September of the second prior year.  If the Index is not published at 
         any time pertinent to this provision, the index used shall be based 
         upon the most closely comparable statistics on the purchasing power of
         the consumer dollar as published by a governmental department or 
         agency.


                                    -3-


<PAGE>

     3.   This Amendment is binding upon and shall inure to the benefit of the
parties hereto and their respective heirs, executors, administrators,
successors in interest, and assigns. Except as expressly amended hereby,
the Lease shall remain unmodified and in full force and effect.














                                    -4-

<PAGE>

     In witness whereof, the parties hereto have executed this
Amendment as of the date first above written.


                                       HAROLD B. CHAPMAN, JR.

                                       /s/ H.B. Chapman, Jr.
                                       ----------------------------------


                                       CETUS CORPORATION

                                       By: /s/ Signature Unreadable
                                          -------------------------------
                                       Its: Sr. VP
                                          -------------------------------











                                    -5-



<PAGE>
                        SECOND AMENDMENT TO LEASE

     THIS SECOND AMENDMENT TO LEASE ("Second Amendment") is made as of the
1st day of January, 1995, between HAROLD B. CHAPMAN, JR., an individual
("Chapman"), and CHIRON CORPORATION, a Delaware corporation ("Chiron").

     THIS SECOND AMENDMENT IS ENTERED on the basis of the following facts,
intentions and understandings of the parties:

     A.   Chapman, as the lessor, and Cetus Corporation ("Cetus"), as the
lessee, entered a Lease ("Original Lease") dated as of July 1, 1983. 
Chiron is the successor to Cetus.

     B.   The Original Lease relates to premises ("Premises") commonly
known as Building M and Building G located at 1400 and 1450 53rd Street in
Emeryville, California. The Premises are more particularly described in the
Original Lease.

     C.   Chapman and Cetus entered an Amendment to Lease ("First
Amendment") dated as of March 20, 1990.  The Original Lease as amended by
the First Amendment is hereinafter referred to as the "Lease." Terms which
are capitalized in this Second Amendment and not defined herein shall have
the meanings set forth in the Lease.

     D.   Chapman and Chiron now desire to amend the Lease as provided in
this Second Amendment.

     E.   Also as of the date of this Second Amendment, Chapman and Chiron
are entering an Option Agreement pursuant to which Chapman is granting to
Chiron an option to purchase the Premises.  The Option Agreement is not to
alter the Lease (as amended by this Second Amendment) in any way.

     F.   The Term of the Lease is seven (7) years, commencing on July 1,
1983.  The Lease provides that Chiron has the option to extend the Lease
for nine (9) additional terms of two (2) years each.  Chiron has already
exercised three (3) of the two (2) year extensions, with the Term of the
Lease, as extended prior to this Second Amendment, to expire on July 1,
1996.

     G.   Chiron desires by this Second Amendment to extend the Term of the
Lease by two (2) additional terms of two (2) years, such that (i) the Term
of the Lease after the extensions pursuant to this Second Amendment shall
expire on June 30, 2000, and (ii) Chiron will have the right, in accordance
with the terms of the Lease (as amended by this Second Amendment), to
extend the


                                   1.
<PAGE>

Term of the Lease after June 30, 2000 by four (4) additional terms of two
(2) years each.

     NOW THEREFORE, IN CONSIDERATION of the mutual covenants and promises
the parties, the parties agree as follows:

     l.   EXERCISE OF OPTIONS.  By this Second Amendment, Chiron hereby
exercises two (2) options, to extend the Term of the Lease for two (2) years
each.  The extensions pursuant to this exercise shall commence on July 1, 1996,
and extend through June 30, 2000.

     2.   REVISED SECTION 10.1. The first sentence of Section 10.1 shall
state in its entirety as follows: "Cetus at its own expense shall carry 
throughout the term hereof property insurance on the Premises to replace the 
Building in compliance with current building codes."

     3.   NO MODIFICATION OF LEASE.  No terms of the Option Agreement shall
alter or modify in any way the terms of the Lease (as amended). For example, 
the failure of Chiron to exercise the option, granted in the Option Agreement,
to purchase the Premises shall not affect Chiron's rights under the Lease
(as amended).

     4.   SUCCESSORS AND ASSIGNS.  This Second Amendment shall be binding
upon and shall inure to the benefit of the parties hereto and their respective
heirs, executors, administrators, successors in interest and assigns.

     5.   REMAINDER OF LEASE UNAFFECTED.  Except as expressly amended by
this Second Amendment, the Lease shall remain in full force and effect and 
unamended.

     IN WITNESS WHEREOF, the parties hereto have executed this Second
Amendment, on the date(s) set forth below, as of the day and year first
above written.

                                   "Chapman"


                                   _____________________________
                                   Harold B. Chapman, Jr., an
                                   individual

                                    2

<PAGE>
                                   
                                   "Chiron"

                                   Chiron Corporation, a Delaware
                                   corporation


                                   By___________________________
                                   Its__________________________

                                   Date_________________________


                                   3.
<PAGE>


                                EXHIBIT C

                           POTENTIAL CLAIMS BY
                          GOVERNMENTAL AGENCIES

     Possible complaint by the County of Alameda which relates to
underground storage tanks on the Property (at the northeast corner of
"Building M").












































                                    
                                EXHIBIT C

                                    



<PAGE>

                                EXHIBIT D
                               ----------

                            TITLE EXCEPTIONS

[LOGO]          CHICAGO TITLE COMPANY OF ALAMEDA COUNTY
      
- -------------------------------------------------------------------------------

Issuing Office:                                  Escrow Location:
22320 Foothill Boulevard                         One Kaiser Plaza, Suite 1450
Hayward, CA 94541                                Oakland, California 94612
Phone:(510)537-2200                              Phone: (510) 451-8888
Fax: (510)537-6922                               Fax: (510) 465-0738

                                                 Escrow No: 105494 KIO 
                                                 Escrow Officer: Kris I. Owens
                                                 RE: CHIRON CORPORATION
                                                 Order No. 000105494 MEW 
                                                 Reference:
                                                 Regarding: 1400 - 53rd Street
                                                 Emeryville, California


- --------------------------------------------------------------------------------

FIRST AMENDED
Dated as of January 12, 1995   at 5:00 P.M.

In response to the above referenced application for a policy of title
insurance,

                 CHICAGO TITLE COMPANY OF ALAMEDA COUNTY

hereby reports that it is prepared to issue, or cause to be issued, as of
the date hereof, a Policy or Policies of Title Insurance describing the
land and the estate or interest therein hereinafter set forth, insuring
against loss which may be sustained by reason of any defect, lien or
encumbrance not shown or referred to as an Exception in Schedule B or not
excluded from coverage pursuant to the printed Schedules, Conditions and
Stipulations of said Policy forms.

The printed Exceptions and Exclusions from the coverage of said Policy or
Policies are set forth in the attached list. Copies of the Policy forms
should be read.  They are available from the office which issued the
report.

Please read the exceptions shown or referred to in Schedule B and the
exceptions and exclusions set forth in the attached list of this report
carefully.  The exceptions and exclusions are meant to provide you with
notice of matters which are not covered under the terms of the title
insurance policy and should be carefully considered. It is important to
note that this preliminary report is not a written representation as to the
condition of title and may not list all liens, defects, and encumbrances
affecting title to the land.

THIS REPORT (AND ANY SUPPLEMENTS OR AMENDMENTS HERETO) IS ISSUED SOLELY FOR
THE PURPOSE OF FACILITATING THE ISSUANCE OF A POLICY OF TITLE INSURANCE AND
NO LIABILITY IS ASSUMED HEREBY.  IF IT IS DESIRED THAT LIABILITY BE ASSUMED
PRIOR TO THE ISSUANCE OF A POLICY OF TITLE INSURANCE, A BINDER OR
COMMITMENT SHOULD BE REQUESTED.

The form of policy of title insurance contemplated by this report is:
       California Land Title Association Standard Coverage Policy


/s/ Miles Williams
- ------------------------
Miles E. Williams

- --------------------------------------------------------------------------------

<PAGE>
                               SCHEDULE A

Order No. 105494         MEW                            Your Ref:
- --------------------------------------------------------------------------------

1. The estate or interest in the land hereinafter described or referred to
   covered by this report is:

A FEE




2. Title to said estate or interest at the date hereof is vested in:

HAROLD B. CHAPMAN, JR., WHO ACQUIRED TITLE AS AN UNMARRIED MAN





3. The land referred to in this report is situated in the State of
   California, County of Alameda and is described as follows:

CITY OF EMERYVILLE

PARCEL "B", PARCEL MAP NO. 2108, FILED JUNE 17, 1977, IN MAP BOOK 97, PAGE
40, ALAMEDA COUNTY RECORDS.

ASSESSOR'S PARCEL NO. 049-1041-049



- --------------------------------------------------------------------------------

<PAGE>


                               SCHEDULE B

Page 1
Order No: 105494    MEW                       Your Ref:
- --------------------------------------------------------------------------------

At the date hereof exceptions to coverage in addition to the printed
Exceptions and Exclusions in the policy form designated on the face page
of this Report would be as follows:

B    1.  The Lien of Supplemental Taxes, if any, assessed pursuant to the
         provisions of Chapter 3.5, Revenue and Taxation Code, Sections 75 et
         seq.


Y    2.  County and City taxes for the Fiscal Year 1994 - 1995
         1st Installment   :  $14,502.81 PAID
         2nd Installment   :  $14,502.81 NOT DUE
         Land              :  $366,429.00
         Improvements      :  $2,228,455.00
         Personal Ppty.    :  NONE
         Exemption         :  NONE
         A.P. No.          :  049-1041-049
         Code Area         :  14-003

C    3.  The herein described property lies within the boundaries of
         a proposed assessment for BAY ST./SHELLMOUND ST. EXTENSION A.D.
         under Act of 1911 or 1915 or 1919, proposed Assessment No.
         (PENDING), in the tentative amount of (AMOUNT PENDING).

K        NOTICE OF ASSESSMENT, BAY STREET-SHELLMOUND STREET EXTENSION
         ASSESSMENT DISTRICT, BY THE CITY OF EMERYVILLE, IN THE AMOUNT OF
         $20,427.00, RECORDED JANUARY 7, 1994, SERIES NO. 94-008822,
         OFFICIAL RECORDS.

D    4.  NON-BUILDABLE AREA OVER THE NORTHWESTERLY 50 FEET OF THE
         NORTHEASTERLY 131.59 FEET OF SAID LAND, AS SET FORTH ON THE
         RECORDED PARCEL MAP.

E    5.  EASEMENT FOR INGRESS, EGRESS AND PUBLIC UTILITY PURPOSES
         OVER THE NORTHWESTERLY PORTION OF SAID LAND, AS SHOWN UPON THE
         RECORDED PARCEL MAP AND AS CONVEYED TO EMERYVILLE ECONOMIC
         DEVELOPMENT FUND, A NON-PROFIT CORPORATION, BY DEED RECORDED
         AUGUST 25, 1977, REEL 5019, IMAGE 505, OFFICIAL RECORDS.

F    6.  Easement, upon the terms, covenants and conditions thereof,
         for the purposes stated herein and incidental purposes created in
         that certain instrument
         Recorded        :    DECEMBER 22, 1986, SERIES NO. 86-322148, OFFICIAL
                              RECORDS
         Granted to      :    CETUS CORPORATION, A DELAWARE CORPORATION
         Purpose         :    ACCESS, INGRESS AND EGRESS PURPOSES
         Affects         :    A PORTION OF SAID PREMISES


G    7.  Unrecorded lease upon the terms and conditions contained therein
         Lessor          :    HAROLD B. CHAPMAN, JR.
         Lessee          :    CETUS CORPORATION


- --------------------------------------------------------------------------------

<PAGE>

                               SCHEDULE B
Page 2                         (continued)

Order No:  105494     MEW                            Your Ref:
- --------------------------------------------------------------------------------

         Disclosed by     :    MEMORANDUM OF LEASE
         Recorded         :    DECEMBER 1, 1987, SERIES NO. 87-320030, OFFICIAL
                               RECORDS

H        Said Lease contains provisions for renewals.

I        The present ownership of said leasehold and other matters affecting the
         interest of the lessee are not shown herein.

J    8.  A Deed of Trust to secure an indebtedness in the original amount shown
         below

         Amount           :    $3,000,000.00
         Dated            :    JANUARY 19, 1988
         Trustor          :    HAROLD B. CHAPMAN, JR., AN UNMARRIED MAN
         Trustee          :    SERRANO RECONVEYANCE COMPANY, A CALIFORNIA
                               CORPORATION
         Beneficiary      :    HOME SAVINGS OF AMERICA, F.A., A FEDERALLY
                               CHARTERED SAVINGS AND LOAN ASSOCIATION
         Address          :    P.O. BOX 7075
                               PASADENA, CALIFORNIA 91109-7075
         Loan No.         :    849904-8
         Recorded         :    FEBRUARY 8, 1988, SERIES NO. 88-033494, OFFICIAL
                               RECORDS

L    9.  Financing Statement to secure an indebtedness of
         Amount           :   NOT SHOWN
         Debtor           :   CETUS CORPORATION
         Secured Party    :   SECURITY PACIFIC EQUIPMENT LEASING, INC.
         Dated            :   NOVEMBER 10, l988
         Recorded         :   JANUARY 18, 1989, SERIES NO. 89-014007, OFFICIAL
                              RECORDS

         (AFFECTS THE LEASEHOLD ESTATE)


M        An amendment thereto was recorded OCTOBER 22, 1993, Series
         No. 93-376002, Official Records, as to A CONTINUATION STATEMENT.

N    10. Unrecorded lease upon the terms and conditions contained therein
         Lessor           :   HAROLD B. CHAPMAN, JR.
         Lessee           :   CHIRON CORPORATION
         Disclosed by     :   NOTICE OF NONRESPONSIBILITY BY OWNER
         Recorded         :   DECEMBER 4, 1992, SERIES NO. 92-394886,
                              OFFICIAL RECORDS

O    11. Any and all unrecorded leases.



- -------------------------------------------------------------------------------





<PAGE>


                               SCHEDULE B
Page 3                         (continued)

Order No:  105494     MEW                            Your Ref:

     P    12.  The possible community interest of the spouse of VESTEE, if
               such person is married.
     
     Q    13.  If extended coverage title insurance will be requested, or
               if this report has been issued to facilitate a request for
               extended coverage title insurance, then the following would also
               be exceptions to coverage:
     
     R         Any facts, rights, interests or claims which are not disclosed
               by the public records but which could by ascertained by making
               inquiry of the parties or persons in possession of the herein
               described land.
     
     S         Any easements, liens (including but not limited to any Statutory
               Liens for labor or materials arising from any on-going or 
               recently completed works of improvement), encumbrances, facts,
               rights, interest or claims which are not shown by the public
               records but which could be ascertained by an inspection of the
               herein described land.
     
     T         Discrepancies, conflicts in boundary lines, shortages in area,
               encroachments or any other facts which a correct survey of the
               herein described land would disclose which are not shown by the
               public records and the requirement that said survey meets with
               the minimum standards for ALTA/ACSM land title surveys.
     
     U         INFORMATIONAL NOTE:
     
               EFFECTIVE JULY 1, 1994, ALL DOCUMENTS TO BE RECORDED IN
               CALIFORNIA MUST CONFORM TO THE FOLLOWING:
     
                    (A)  A PAGE FOR THE PURPOSE OF RECORDING SHALL BE ONE 
                         PRINTED SIDE OF A SINGLE PIECE OF PAPER WHICH IS 8-1/2
                         INCHES BY 11 INCHES.
          
                    (B)  A SHEET SHALL BE ONE PRINTED SIDE OF A SINGLE PIECE OF
                         PAPER WHICH IS NOT EXACTLY 8-1/2 INCHES BY 11 INCHES
                         BUT NOT GREATER THAN 8-1/2 INCHES BY 14 INCHES.
          
                    (C)  IF A PAGE OR SHEET DOES NOT CONFORM TO THE DIMENSIONS
                         OF 8-1/2 INCHES BY 11 INCHES, THE RECORDER SHALL CHARGE
                         $3.00 EXTRA PER PAGE OR SHEET OF THE DOCUMENT.
          
                    THESE CHANGES ARE PURSUANT TO GOVERNMENT CODE SECTIONS 
                    27201, 27361 AND 27361.5 WHICH WERE ENACTED IN THE 1992 
                    LEGISLATIVE SESSION, TO BE EFFECTIVE JULY 1, 1994.
          
                    (D)  THE ALAMEDA COUNTY RECORDER INTERPRETS THE ABOVE 
                         STATUTES TO EXCLUDE FROM RECORDING, AND THEREFORE WILL
                         NOT ACCEPT, ANY DOCUMENT CONTAINING ONE OR MORE SHEETS
                         OR PAGES GREATER THAN 8-1/2 INCHES BY 14 INCHES.
          

<PAGE>



                                  SCHEDULE B
Page 4                            (continued)

Order No:  105494     MEW                            Your Ref:

W         NOTE:

          According to the Public Records, no Deed conveying the property
          described in this Report has been recorded within a period of two
          years prior to the date of this Report, except as shown herein:
     
          None

X         MEW/lt
          1/20/95


<PAGE>



                                 NOTICE

SECTION 12413.1 OF THE CALIFORNIA INSURANCE CODE, EFFECTIVE JANUARY 1, 1990,
REQUIRES THAT ANY TITLE INSURANCE COMPANY, UNDERWRITTEN TITLE COMPANY, OR
CONTROLLED ESCROW COMPANY HANDLING FUNDS IN AN ESCROW OR SUB-ESCROW CAPACITY,
WAIT A SPECIFIED NUMBER OF DAYS AFTER DEPOSITING FUNDS, BEFORE RECORDING ANY
DOCUMENTS IN CONNECTION WITH THE TRANSACTION OR DISBURSING FUNDS.  THIS
STATUTE ALLOWS FOR FUNDS DEPOSITED BY WIRE TRANSFER TO BE DISBURSED THE SAME
DAY AS DEPOSIT. IN THE CASE OF CASHIER'S CHECKS OR CERTIFIED CHECKS, FUNDS
MAY BE DISBURSED THE NEXT DAY AFTER DEPOSIT. IN ORDER TO AVOID UNNECESSARY
DELAYS OF THREE TO SEVEN DAYS, OR MORE, PLEASE USE WIRE TRANSFER, CASHIER'S
CHECKS, OR CERTIFIED CHECKS WHENEVER POSSIBLE.

IF YOU HAVE ANY QUESTIONS ABOUT THE EFFECT OF THIS NEW LAW, PLEASE CONTACT
YOUR LOCAL CHICAGO TITLE OFFICE FOR MORE DETAILS.


                                  Chicago Title [LOGO]



<PAGE>

                LIST OF PRINTED EXCEPTIONS AND EXCLUSIONS

    CALIFORNIA LAND TITLE ASSOCIATION STANDARD COVERAGE POLICY - 1990

                        EXCLUSIONS FROM COVERAGE
The following matters are expressly excluded from the coverage of this
policy and the Company will not pay loss or damage, costs, attorneys' fees
or expenses which arise by reason of:
1.   (a)  Any law, ordinance or governmental regulation (including but
          not limited to building and zoning laws, ordinances, or
          regulations) restricting, regulating, prohibiting or relating to
          (i) the occupancy, use, or enjoyment of the land; (ii) the
          character, dimensions or location of any improvement now or
          hereafter erected on the land; (iii) a separation in ownership or
          a change in the dimensions or area of the land or any parcel of
          which the land is or was a part; or (iv) environmental
          protection, or the effect of any violation of these laws,
          ordinances or governmental regulations, except to the extent that
          a notice of the enforcement thereof or a notice of a defect, lien
          or encumbrance resulting from a violation or alleged violation
          affecting the land has been recorded in the public records at
          Date of Policy.
     
     (b)  Any governmental police power not excluded by (a) above,
          except to the extent that a notice of the exercise thereof or a
          notice of a defect, lien or encumbrance resulting from a
          violation or alleged violation affecting the land has been
          recorded in the public records at Date of Policy.
     
2.        Rights of eminent domain unless notice of the exercise
          thereof has been recorded in the public records at Date of
          Policy, but not excluding from coverage any taking which has
          occurred prior to Date of Policy which would be binding on the
          rights of a purchaser for value without knowledge.
     
3.        Defects, liens, encumbrances, adverse claims or other matters:
     (a)  whether or not recorded in the public records at Date of
          Policy, but created, suffered, assumed or agreed to by the
          insured claimant;
     (b)  not known to the Company, not recorded in the public records
          at Date of Policy, but known to the insured claimant and not
          disclosed in writing to the Company by the insured claimant prior
          to the date the insured claimant became an insured under this
          policy;
     (c)  resulting in no loss or damage to the insured claimant;
     (d)  attaching or created subsequent to Date of Policy; or
     (e)  resulting in loss or damage which would not have been
          sustained if the insured claimant had paid value for the insured
          mortgage or the estate or interest insured by this policy.
     
4.        Unenforceability of the lien of the insured mortgage because
          of the inability or failure of the insured at Date of Policy, or
          the inability or failure of any subsequent owner of the
          indebtedness, to comply with applicable doing business laws of
          the state in which the land is situated.     

5.        Invalidity or unenforceability of the lien of the insured
          mortgage, or claim thereof, which arises out of the transaction
          evidenced by the insured mortgage and is based upon usury or any
          consumer credit protection or truth-in-lending law.
     
6.        Any claim which arises out of the transaction vesting in the
          insured the estate or interest insured by this policy or the
          transaction creating the interest of the insured lender, by reason
          of the operation of federal bankruptcy, state insolvency or
          similar creditors' rights laws.
     
     
     
                            EXCEPTIONS FROM COVERAGE
                                   
This policy does not insure against loss or damage (and the Company will
not pay costs, attorneys' fees or expenses) which arise by reason of:
1.  Taxes or assessments which are not shown as existing liens by the
    records of any taxing authority that levies taxes or assessments on
    real property or by the public records.

    Proceedings by a public agency which may result in taxes or
    assessments, or notices of such proceedings, whether or not shown by
    the records of such agency or by the public records.

2.  Any facts, rights, interests or claims which are not shown by the
    public records but which could be ascertained by an inspection of the
    land or which may be asserted by persons in possession thereof.

3.  Easements, liens or encumbrances, or claims thereof, which are not
    shown by the public records.

4.  Discrepancies, conflicts in boundary lines, shortage in area,
    encroachments, or any other facts which a correct survey would
    disclose, and which are not shown by the public records.

5.  (a) Unpatented mining claims; (b) reservations or exceptions in
    patents or in Acts authorizing the issuance thereof; (c) water rights,
    claims or title to water, whether or not the matters excepted under
    (a), (b) or (c) are shown by the public records.


<PAGE>

  AMERICAN LAND TITLE ASSOCIATION RESIDENTIAL TITLE INSURANCE POLICY (6-1-87)

                                   EXCLUSIONS

In addition to the exceptions in Schedule B, you are not insured against
loss, costs, attorney's fees and expenses resulting from:

     1.  Governmental policy power, and the existence or violation of any
         law or government regulation.  This includes building and zoning
         ordinances and also laws and regulations concerning:
          -  land use                       -  land division
          -  improvements on the land       -  environmental protection

     This exclusion does not apply to the violations or the enforcement of
     these matters which appear in the public records at Policy Date. This
     exclusion does not limit the zoning coverage described in Items 12 and 13
     of Covered Title Risks.

     2.  The right to take the land by condemning it, unless:
          -  a notice of exercising the right appears in the public records
             on the Policy Date
          -  the taking happened prior to the Policy Date and is binding on
             you if you bought the land without knowing of the taking.
               
     3.  Title Risks:
          -  that are created, allowed, or agreed to by you
          -  that are known to you, but not to us, on the Policy Date - unless
             they appeared in the public records
          -  that result in no loss to you
          -  that first affect your title after the Policy Date - this does not
             limit the labor and material lien coverage in Item 8 of Covered
             Title Risks
               
     4.  Failure to pay value for your title.

     5.  Lack of a right:
          -  to any land outside the area specifically described and referred
             to in Item 3 of Schedule A, or
          -  in streets, alleys, or waterways that touch your land
               
         This exclusion does not limit the access coverage in Item 5 of
         Covered Title Risks.



                            EXCEPTIONS FROM COVERAGE
                                    
In addition to the Exclusions, you are not insured against loss, costs,
attorneys' fees and expenses resulting from:

     1.  Someone claiming an interest in your land by reason of:
         A. Easements not shown in the public records
         B. Boundary disputes not shown in the public records
         C. Improvements owned by your neighbor placed on your land

     2.  If, in addition to a single family residence, your existing
         structure consists of one or more Additional Dwelling Units, Item 12 of
         Covered Title Risks does not insure you against loss, costs, attorneys'
         fees, and expenses resulting from:

         A. The forced removal of any Additional Dwelling Unit, or,

         B. The forced conversion of any Additional Dwelling Unit back
            to its original use.

         If said Additional Dwelling Unit was either constructed or
         converted to use as a dwelling unit in violation of any law or
         government regulation.

         
<PAGE>

              AMERICAN LAND TITLE ASSOCIATION LOAN POLICY (10-17-92)
                      WITH ALTA ENDORSEMENT - FORM 1 COVERAGE
                                       and
          AMERICAN LAND TITLE ASSOCIATION LEASEHOLD LOAN POLICY (10-17-92)
                      WITH ALTA ENDORSEMENT - FORM 1 COVERAGE

                             EXCLUSIONS FROM COVERAGE

The following matters are expressly excluded from the coverage of this
policy and the Company will not pay loss or damage, costs, attorneys' fees
or expenses which arise by reason of:

1.  (a)  Any law, ordinance or governmental regulation (including but not
         limited to building and zoning laws, ordinances, or regulations)
         restricting, regulating, prohibiting or relating to (i) the occupancy,
         use, or enjoyment of the land; (ii) the character, dimensions or
         location of any improvement now or hereafter erected on the land;
         (iii) a separation in ownership or a change in the dimensions or area
         of the land or any parcel of which the land is or was a part; or (iv)
         environmental protection, or the effect of any violation of these laws,
         ordinances or governmental regulations, except to the extent that a
         notice of the enforcement thereof or a notice of a defect, lien or
         encumbrance resulting from a violation or alleged violation affecting
         the land has been recorded in the public records at Date of Policy.

    (b)  Any governmental police power not excluded by (a) above, except
         to the extent that a notice of the exercise thereof or a notice of a
         defect, lien or encumbrance resulting from a violation or alleged
         violation affecting the land has been recorded in the public records
         at Date of Policy.

2.       Rights of eminent domain unless notice of the exercise thereof
         has been recorded in the public records at Date of Policy, but not
         excluding from coverage any taking which has occurred prior to Date of
         Policy which would be binding on the rights of a purchaser for value
         without knowledge.

3.       Defects, liens, encumbrances, adverse claims or other matters:
    (a)  created, suffered, assumed or agreed to by the insured claimant;
    (b)  not known to the Company, not recorded in the public records
         at Date of Policy, but known to the insured claimant and not
         disclosed in writing to the Company by the insured claimant prior
         to the date the insured claimant became an insured under this
         policy;
    (c)  resulting in no loss or damage to the insured claimant;
    (d)  attaching or created subsequent to Date of Policy (except to
         the extent that this policy insures the priority of the lien of
         the insured mortgage over any statutory lien for services, labor
         or material or to the extent insurance is afforded herein as to
         assessments for street improvements under construction or
         completed at Date of Policy); or
    (e)  resulting in loss or damage which would not have been
         sustained if the insured claimant had paid value for the insured
         mortgage.
     
4.       Unenforceability of the lien of the insured mortgage because
         of the inability or failure of the insured at Date of Policy, or
         the inability or failure of any subsequent owner of the
         indebtedness, to comply with applicable doing business laws of
         the state in which the land is situated.
     
5.       Invalidity or unenforceability of the lien of the insured
         mortgage, or claim thereof, which arises out of the transaction
         evidenced by the insured mortgage and is based upon usury or any
         consumer credit protection or truth in lending law.
     
6.       Any statutory lien for services, labor or materials (or the
         claim or priority of any statutory lien for services, labor or
         materials over the lien of the insured mortgage) arising from an
         improvement or work related to the land which is contracted for
         and commenced subsequent to Date of Policy and is not financed in
         whole or in part by proceeds of the indebtedness secured by the
         insured mortgage which at Date of Policy the insured has advanced
         or is obligated to advance.
     
7.       Any claim, which arises out of the transaction creating the
         interest of the mortgagee insured by this policy, by reason of
         the operation of federal bankruptcy, state insolvency, or similar
         creditors' rights laws, that is based on:
         (i)  the transaction creating the interest of the insured
              mortgagee being deemed a fraudulent conveyance or fraudulent
              transfer; or
        (ii)  the subordination of the interest of the insured mortgagee
              as a result of the application of the doctrine of equitable
              subordination; or
       (iii)  the transaction creating the interest of the insured
              mortgagee being deemed a preferential transfer except where the
              preferential transfer results from the failure:
              (a)  to timely record the instrument of transfer; or
              (b)  of such recordation to impart notice to purchaser for
                   value or a judgment or lien creditor.

The above policy forms may be issued to afford either Standard Coverage or
Extended Coverage.  In addition to the above Exclusions from Coverage, the
Exceptions from Coverage in a Standard Coverage policy will also include
the following General Exceptions:

                           EXCEPTIONS FROM COVERAGE

The policy does not insure against loss or damage (and the Company will not
pay costs, attorneys' fees or expenses) which arise by reason of:

1.   Taxes or assessments which are not shown as existing liens by the
records of any taxing authority that levies taxes or assessments on real
property or by the public records.
     Proceedings by a public agency which may result in taxes or
assessments, or notices of such proceedings, whether or not shown by the
records of such agency or by the public records.

2.   Any facts, rights, interests or claims which are not shown by the
public records but which could be ascertained by an inspection of the land
or by making inquiry of persons in possession thereof.

3.   Easements, liens or encumbrances, or claims thereof, which are not
shown by the public records.

4.   Discrepancies, conflicts in boundary lines, shortage in area,
encroachments, or any other facts which a correct survey would disclose,
and which are not shown by the public records.

5.   (a) Unpatented mining claims; (b) reservations or exceptions in
patents or in Acts authorizing the issuance thereof; (c) water rights,
claims or title to water, whether or not the matters excepted under (a),
(b) or (c) are shown by the public records.


<PAGE>

           AMERICAN LAND TITLE ASSOCIATION OWNER'S POLICY (10-17-92)
                                      and
      AMERICAN LAND TITLE ASSOCIATION LEASEHOLD OWNER'S POLICY (10-17-92)

                           EXCLUSIONS FROM COVERAGE

The following matters are expressly excluded from the coverage of this
policy and the Company will not pay loss or damage, costs, attorneys' fees
or expenses which arise by reason of:
1.  (a)   Any law, ordinance or governmental regulation (including 
          but not limited to building and zoning laws, ordinances, or 
          regulations) restricting, regulating, prohibiting or relating to 
          (i) the occupancy, use, or enjoyment of the land; (ii) the 
          character, dimensions or location of any improvement now or 
          hereafter erected on the land; (iii) a separation in ownership or a 
          change in the dimensions or area of the land or any parcel of which 
          the land is or was a part; or (iv) environmental protection, or the 
          effect of any violation of these laws, ordinances or governmental 
          regulations, except to the extent that a notice of the enforcement 
          thereof or a notice of a defect, lien or encumbrance resulting from 
          a violation or alleged violation affecting the land has been 
          recorded in the public records at Date of Policy.
          
    (b)   Any governmental police power not excluded by (a) above, except to 
          the extent that a notice of the exercise thereof or a notice of a 
          defect, lien or encumbrance resulting from a violation or alleged 
          violation affecting the land has been recorded in the public records 
          at Date of Policy.
     
2.        Rights of eminent domain unless notice of the exercise thereof has 
          been recorded in the public records at Date of Policy, but not 
          excluding from coverage any taking which has occurred prior to Date 
          of Policy which would be binding on the rights of a purchaser for 
          value without knowledge.

3.        Defects, liens, encumbrances, adverse claims or other matters:
    (a)   created, suffered, assumed or agreed to by the insured claimant;
    (b)   not known to the Company, not recorded in the public records at Date 
          of Policy, but known to the insured claimant and not disclosed in 
          writing to the Company by the insured claimant prior to the date the 
          insured claimant became an insured under this policy;
    (c)   resulting in no loss or damage to the insured claimant;
    (d)   attaching or created subsequent to Date of Policy; or
    (e)   resulting in loss or damage which would not have been sustained if 
          the insured claimant had paid value for the estate or interest insured
          by this policy.

4.        Any claim, which arises out of the transaction vesting in the insured 
          the estate or interest insured by this policy, by reason of the 
          operation of federal bankruptcy, state insolvency, or similar 
          creditors' rights laws, that is based on:
          (i)  the transaction creating the estate or interest insured by this 
               policy being deemed a fraudulent conveyance or fraudulent 
               transfer; or
          (ii) the transaction creating the estate or interest insured by this 
               policy being deemed a preferential transfer except where the 
               preferential transfer results from the failure.
               (a)  to timely record the instrument of transfer; or
               (b)  of such recordation to impart notice to a purchaser for 
                    value or a judgment or lien creditor.



The above policy forms may be issued to afford either Standard Coverage or
Extended Coverage.  In addition to the above Exclusions from Coverage, the
Exceptions from Coverage in a Standard Coverage policy will also include
the following General Exceptions:

                        EXCEPTIONS FROM COVERAGE

This policy does not insure against loss or damage (and the Company will
not pay costs, attorneys' fees or expenses) which arise by reason of:

1.   Taxes or assessments which are not shown as existing liens by the
records of any taxing authority that levies taxes or assessments on real
property or by the public records.
     Proceedings by a public agency which may result in taxes or
assessments, or notices of such proceedings, whether or not shown by the
records of such agency or by the public records.
2.   Any facts, rights, interests or claims which are not shown by the
public records but which could be ascertained by an inspection of the land
or by making inquiry of persons in possession thereof.
3.   Easements, liens or encumbrances, or claims thereof, which are not
shown by the public records.
4.   Discrepancies, conflicts in boundary lines, shortage in area,
encroachments, or any other facts which a correct survey would disclose,
and which are not shown by the public records.
5.   (a) Unpatented mining claims; (b) reservations or exceptions in
patents or in Acts authorizing the issuance thereof; (c) water rights,
claims or title to water, whether or not the matters excepted under (a),
(b) or (c) are shown by the public records.


<PAGE>


                                     EXHIBIT E
                                    -----------

                           MEMORANDUM OF OPTION AGREEMENT
                          --------------------------------

RECORDING REQUESTED BY            |
AND WHEN RECORDED MAIL TO:        |
                                  |
Brobeck, Phleger & Harrison       |
One Market                        |
Spear Street Tower, 24th Floor    |
San Francisco, California 94105   |
Attn: A. Bruce Gilmore, Esq.      |
                                  |
                                  |THE AREA ABOVE IS RESERVED FOR RECORDER'S USE
- --------------------------------------------------------------------------------

                     MEMORANDUM OF OPTION AGREEMENT

- --------------------------------------------------------------------------------


     THIS MEMORANDUM OF OPTION AGREEMENT ("Memorandum") is entered as of the 
____ day of June, 1995, by and between HAROLD B. CHAPMAN, JR., an individual 
("Chapman"), and CHIRON CORPORATION, a Delaware corporation ("Chiron").

     THIS MEMORANDUM is entered on the basis of the following facts, 
intentions and understandings of the parties:

     A.   Chapman is the owner of the real property described in EXHIBIT 1, 
attached hereto.

     B.   Chapman, as optionor, and Chiron, as optionee, have entered an 
Option Agreement dated as of January 1, 1995.  Pursuant to the Option 
Agreement, Chiron has the option ("Option") to purchase the Property from 
Chapman.

     C.   Chapman and Chiron desire to execute and record this Memorandum to 
give notice of the Option.

     NOW, THEREFORE, in consideration of the mutual covenants and promises of 
the parties, the parties agree as follows:

     l.   GRANT OF OPTION. Chapman hereby grants Chiron the Option to 
purchase the Property, subject to and in accordance with the terms set forth 
in the Option Agreement.

     2.   TERM.  The term of the Option commenced as of January 1, 1995. If 
not previously terminated, the term shall expire on December 31, 1999.

                                EXHIBIT E
                                ---------
                                   1.


<PAGE>


     3.   CONFLICT. In the event of any conflict between the terms of this 
Memorandum and the terms of the Option Agreement, the terms of the Option 
Agreement shall control.

     4.   NOTICE. The purpose of this Memorandum is to give notice of the 
Option.

     IN WITNESS WHEREOF, the parties have executed this Memorandum, on the 
date(s) set forth below, as of the day and year first above written.

                              "Chapman"


                              -------------------------------------
                              Harold B. Chapman, Jr., an individual

                              Date:
                                   -------------------------------


                              "Chiron"

                              CHIRON CORPORATION, a Delaware
                              corporation


                              By:
                                  ---------------------------------
                                 Name: 
                                       ----------------------------
                                 Its: 
                                      -----------------------------
                              Date: 
                                    -------------------------------











                                EXHIBIT E
                                ---------
                                   2.



<PAGE>

                                EXHIBIT 1

                          PROPERTY DESCRIPTION


CITY OF EMERYVILLE

PARCEL "B", PARCEL MAP NO. 2108, FILED JUNE 17, 1977, IN MAP BOOK 97, PAGE
40, ALAMEDA COUNTY RECORDS.

ASSESSOR'S PARCEL NO. 049-1041-049


<PAGE>


[CHIRON LETTERHEAD]




                            February 28, 1996


[GRAPHIC]


VIA HAND DELIVERY
AND U.S. MAIL


Harold B. Chapman, Jr.
2900 Main Street
Alameda, California 94501

     Re:  Option Agreement for Real Property and Improvements
          (Including Buildings "M" and "G") in Emeryville, California
          -----------------------------------------------------------

Dear Mr. Chapman:

     Chiron Corporation, as Buyer, and you, as Seller, entered into an Option 
Agreement dated as of January 1, 1995.  The Option Agreement relates to real 
property ("Property") in Emeryville, California, which includes Buildings "M" 
and "G." The Property is more particularly described in the Option Agreement.

     The Option Agreement provides that Chiron has the option ("Option") to 
purchase the Property by exercising the Option prior to January 1, 2000 by 
delivering a written notice ("Exercise Notice") to you by registered mail or 
personal delivery stating that Chiron desires to close escrow.  This 
letter constitutes the Exercise Notice under the Option Agreement.

     Section 11.a of the Option Agreement provides that close of escrow 
("Close of Escrow") is to occur on the date ("Closing Date") determined by 
you; provided that (i) the Closing Date shall be not later than February 27, 
1997 (one (1) year after the date of this Exercise Notice), (ii) the Closing 
Date shall not be earlier than August 27, 1996 (six (6) months after the date 
of this Exercise Notice) and (iii) you will give Chiron not less than 
forty-five (45) days' prior written notice of the Closing Date.

     You are not required to notify Chiron of the Closing Date at this time.  
However, Chiron would appreciate your notifying me as soon as possible of the 
date you desire to be the Closing Date.


CHIRON CORPORATION - 4560 Horton Street - Emeryville, CA - 94608-2916 - 
510-655-8730 LAW DEPARTMENT - General Fax: 510-654-5360 - Intellectual 
Property Fax: 510-655-3542

<PAGE>

Harold B. Chapman, Jr.                                         February 28, 1996
                                                                          Page 2

     It is my understanding that the Option Agreement provides for 
flexibility in establishing the Closing Date in order to allow you to effect 
the transfer of the Property as an exchange in accordance with Section 1031 
of the Internal Revenue Code.  Under Section 1031, you may be entitled to 
defer the taxes otherwise due upon the transfer of the Property, even if you 
acquire "replacement property" after you transfer the Property to Chiron.  It 
is Chiron's hope that, based on the flexibility provided for transfers 
pursuant to Section 1031 you will elect to have the Closing Date as soon as 
possible after August 27, 1996.

     I am also sending a copy of this letter to Eugene Schneider, your 
counsel.  If Mr. Schneider or you have any questions regarding this letter, 
please contact Bruce Gilmore (415) 442-1444.

     Thank you for your assistance in this matter.  I look forward to working 
with you as we conclude the transfer of the Property.


                                       Very truly yours,

                                       /s/ Ed Bailey

                                       Ed Bailey
                                       Director, Facilities Planning



cc:    Mr. Thomas Peterson
       A. Bruce Gilmore, Esq. (via Facsimile)
       Eugene Schneider, Esq. (via U.S. Mail)





<PAGE>

                                                                   EXHIBIT 10.56

                          [CONFIDENTIAL TREATMENT REQUESTED]

[Certain confidential information has been omitted from the Agreement and filed
separately with the Securities and Exchange Commission pursuant to a request by
Registrant for confidential treatment pursuant to Rule 24b-2.  The omitted
confidential information has been identified by the following statement:
"CONFIDENTIAL TREATMENT REQUESTED".]

                        AMENDED AND RESTATED LICENSE AGREEMENT

    This AMENDED AND RESTATED LICENSE AGREEMENT effective as of April 1, 1996
(this "Agreement") between CIBA CORNING DIAGNOSTICS CORP., a corporation
organized under the laws of the State of Delaware, U.S.A., that intends to
change its name to Chiron Diagnostics Corp. effective on or about November 1,
1996 (hereinafter "Chiron") and BIOANALYSIS LIMITED, a corporation organized
under the laws of the United Kingdom of Great Britain and Northern Ireland
(hereinafter "Bioanalysis").

    WHEREAS, Chiron (as assignee of Corning Glass Works) and Bioanalysis are
parties to an agreement dated as of December 6, 1984 (the "Original Agreement")
relating to the sublicense to Chiron by Bioanalysis of certain technology
licensed by Bioanalysis from the University of Wales College of Medicine
(formerly known as the Welsh National School of Medicine and hereinafter
referred to as "UWCM"); and

    WHEREAS, certain disputes have arisen between Chiron and Bioanalysis under
the Original Agreement, which disputes the parties wish to resolve pursuant to a
Settlement Agreement of even date herewith (the "Settlement Agreement"); and

    WHEREAS, the terms of the Settlement Agreement provide for the amendment
and restatement of the Original Agreement as set forth herein;

    NOW, THEREFORE, Chiron and Bioanalysis agree to amend and restate the
Original Agreement to read in its entirety as follows:


<PAGE> 

1.DEFINITIONS

    When used in this Agreement with initial capitals, the terms defined in
this Section 1 shall have the respective meanings set forth below:

    a."ADDITIONAL ROYALTY ACCOUNT" shall have the meaning specified in Section
3(c).

    b."AE" shall mean any chemiluminescent aryl acridinium esters.

    c."AFFILIATE" of a party shall mean a corporation or any other business
entity, in whatever country organized, which, directly or indirectly, controls,
is controlled by or is under common control with such party.  For this purpose,
control shall mean the ownership of more than 50% of the issued share capital or
the legal power to direct or cause the direction of the general management and
policies of the party in question.  Notwithstanding the foregoing, in the case
of Chiron, "Affiliate" shall (i) include Ciba Corning Diagnostics de Mexico S.A.
(which intends to change its name on or about November 1, 1996 to Chiron S.A. de
C.V.), so long as Chiron continues to own at least 49% of the voting stock of
that corporation, and (ii) exclude Ciba-Geigy Limited, a Switzerland corporation
("Ciba"), and any subsidiaries of Ciba, unless and until such time as Ciba and
Chiron Corporation may mutually agree upon the terms and conditions upon which
Ciba may be deemed an Affiliate of Chiron for purposes of this Agreement.

    d."BAYER AGREEMENT" means the Licensing Agreement dated as of December 18,
1986 between Bayer Corporation (formerly known as Miles Laboratories, Inc.) and
Chiron.

    e."BAYER OFFSET ACCOUNT" shall have the meaning specified in Section 3(b).

    f."BIOANALYSIS PRODUCTS" shall mean the products identified in Schedule A.


                                          2

<PAGE> 

    g."CAMPBELL PATENTS" shall mean U.S. Patent No. 4,946,958, any foreign
counterpart patent of U.S. Patent No. 4,946,958 or any continuation, division,
re-issue or re-examination either the U.S. patent above named or its foreign
counterpart.

    h."CLAIM" shall mean an issued patent claim which defines an invention
which the patentee has been granted the right to exclude others from making,
using, or selling throughout the granting country.  The term does not include
any patent claim which has been disclaimed, canceled, or finally adjudicated to
be invalid.

    i."CLOSING DATE" shall mean July 1, 1996.

    j."IMMUNOASSAY" shall mean any assay wherein the analyte of interest is an
antibody or protein or is determined by the binding thereto of an antibody or
other specific binding protein.

    k."LICENSED PATENTS" shall mean all patents relating to Immunoassays
employing AE labels now or hereafter legally or beneficially owned or controlled
by Bioanalysis ("Bioanalysis Patents") or UWCM ("UWCM Patents"), including all
of the Campbell Patents, provided that "Licensed Patents" shall not include any
patent arising out of an invention first conceived on or after, and with an
earliest claimed priority date on or after, April 1, 1996.  The list of the
Licensed Patents and the pending applications which may result in the issuance
of Licensed Patents ("Licensed Patent Applications") is attached hereto as
Schedule B, provided that any omission from such list shall not affect the
status of a patent which would otherwise be a Licensed Patent hereunder.

    l."LICENSED PRODUCTS" shall mean Immunoassays or components for
Immunoassays for use in (i) human healthcare and (ii) pre-clinical and
laboratory research whether or not directed to human healthcare, the
manufacture, use or sale of which would, in the absence of a license, infringe a
Claim of a Licensed Patent.


                                          3

<PAGE> 

    m."NET SALES REVENUE" shall mean the amount billed by Chiron or its
Affiliates or sublicensees to third parties for the sale of Royalty Products or
performance of assays using Royalty Products, less discounts allowed; less
credits for customers' returns and allowances; less the value of the instrument
and service components of an operating or capital lease for which the charges
are included in the price of Royalty Products purchased by the lessee; less
charges for freight handling and transportation paid by Chiron; and less sales
and use taxes and other similar taxes incurred, all to the extent reasonable and
as determined in accordance with generally accepted accounting practices and
industry practices.  Notwithstanding the foregoing, if Chiron or its Affiliates
or sublicensees bills a third party for performance of an assay using a Royalty
Product, the amount of Net Sales Revenue shall be equal to the average Net Sales
Revenue for sales of such Royalty Product in the country in which such assay is
performed during the quarter in which such assay is performed, or, if such
Royalty Product is not sold for commercial use in such country during such
quarter, the worldwide average Net Sales Revenue for sales of such Royalty
Product for such quarter, or, if such Royalty Product is not sold commercially
in any country, a reasonable apportionment shall be made of the gross amount
invoices for performance of the assay between the value of the assay and the
value of the laboratory services associated therewith, taking into account the
average selling prices of similar products, such apportionment to be negotiated
in good faith between the parties and arbitrated if they are unable to agree. 
No royalty shall be due upon a sale of a Royalty Product by Chiron to an
Affiliate.  Instead, royalty shall be due when such Royalty Product is re-sold
to or used to perform an assay for a third party, and Net Sales Revenue shall be
calculated based on the invoiced price to such party.  Royalty shall accrue only
once as to any Royalty Product.

    n."PRIME RATE" shall mean, as to each of Chiron's fiscal quarters, the
prime rate of interest as published on the last business day of such quarter in
the Wall Street Journal, provided that Chiron may substitute for the Wall Street
Journal any comparable print or electronic publication, provided that such
substitute publication is used generally by Chiron for such purposes in its


                                          4

<PAGE> 

accounting operations.  Chiron agrees to notify Bioanalysis of any change in the
source it uses for the Prime Rate.

    o."PROPRIETARY INFORMATION" - Information of any kind, including without
limitation, inventions, technology, disclosures, processes, systems, methods,
formulae, patent applications, machinery, materials, research activities and
plans, costs of production, contract forms, prices, volume of sales, promotional
methods, and lists of names or classes of customers, know-how and trade secrets,
owned or controlled by a party which such party regards as valuable and holds
confidentially other than information which (i) was known by the receiving party
prior to its disclosure by the disclosing party; (ii) is or becomes public
knowledge without fault of the receiving party; (iii) is obtained or derived by
the receiving party from a third party which, to the best knowledge of the
receiving party after appropriate inquiry, is lawfully in possession of such
information and has the right to disclose the information to the receiving party
on a non-confidential basis; or (iv) is developed or derived by the receiving
party, prior or subsequent to its disclosure by the disclosing party,
independently and without resort to the information which was disclosed by the
disclosing party.

    p."ROYALTY ADVANCE" shall have the meaning specified in Section 3(a)(ii).

    q."ROYALTY PRODUCTS" shall have the following meanings at the respective
times specified below:

         i.Until the earlier of August 7, 2007 or depletion of the Bayer Offset
Account, "Royalty Products" shall mean (A) so long as at least one Claim of a
Campbell Patent remains in force anywhere in the world, Immunoassays or
components for Immunoassays that use an AE label, regardless of whether such
products constitute Licensed Products hereunder, except as to any product which
is an Independent Sublicensee Product referred to in clause (ii) of this
Paragraph 1(q); or (B) if no Claim of a Campbell Patent remains in force,
Immunoassays or components of Immunoassays, the manufacture, use or sale of
which would, in the absence of a license, infringe a


                                          5

<PAGE> 

Claim of a Licensed Patent in force in country in which such manufacture, use or
sale occurs, as determined by applicable principles of patent law.

         ii.Thereafter, and at all times with respect to any products of a
sublicensee which are not designed for use on a Chiron instrument and are not
labelled with a Chiron trademark ("Independent Sublicensee Products"), "Royalty
Products" shall mean Immunoassays or components for Immunoassays the
manufacturer, use or sale of which would, in the absence of a license, infringe
a Claim of a Campbell Patent in force in a country in which such manufacture,
use or sale occurs, as determined by applicable principles of patent law.

    r."UWCM LICENSE" shall mean the Agreement dated as of July 12, 1984 between
UWCM and Bioanalysis pursuant to which UWCM licensed the UWCM Patents to
Bioanalysis.

2.GRANT OF LICENSE; LIMITATIONS

    a.GRANT.  Bioanalysis hereby grants to Chiron a world-wide sublicense under
the UWCM Patents and a world-wide license under the Bioanalysis Patents to
develop, make, have made, import, use, offer to sell and sell Licensed Products.
Such sublicense and license (i) shall be exclusive as to Licensed Products for
use in human healthcare and pre-clinical and laboratory research directed to
human healthcare and non-exclusive as to Licensed Products for use in
pre-clinical and laboratory research not directed to human health care and (ii)
shall include the right to grant sublicenses in accordance with the terms of
Section 5 hereof; provided, however, that pre-clinical and laboratory research
conducted by Bioanalysis with application to human healthcare shall not infringe
Chiron's exclusive license so long as that research has potential application to
fields other than human healthcare.

    b.RESERVATION OF RIGHTS IN GRANTOR.  Notwithstanding the exclusive licenses
granted to Chiron hereunder, Bioanalysis reserves to itself the non-exclusive
right (with right of sublicense to


                                          6

<PAGE> 

third parties or Affiliates with whom Bioanalysis enters into collaborative
arrangements for the development, manufacture and marketing of Bioanalysis
Products) to make, have made, import, use, offer to sell and sell the
Bioanalysis Products.

    c.RIGHTS LIMITED TO LICENSED PRODUCTS.  Nothing herein grants to Chiron any
rights under the Licensed Patents with respect to the manufacture, use or sale
of any products other than Licensed Products.  Without limiting  the generality
of the foregoing, nothing herein shall be construed as a grant to Chiron of any
rights under the Licensed Patents to develop, make, have made, import, use,
offer to sell or sell nucleic acid hybridization assays or any other assays for
which rights are not specifically granted to Chiron herein.

    d.NO LIMITATIONS EXCEPT UNDER PATENTS.  As between the parties to this
Agreement, the field of use restrictions contained herein prohibit the
manufacture, use or sale of any product by either party only to the extent that
such manufacture, use or sale constitutes infringement of a Claim of a patent in
force in the jurisdiction in which such activity occurs.

    e.PROPRIETARY INFORMATION.  Bioanalysis and UWCM have provided Chiron with
information relating to the use of acridinium esters in immunoassays and binding
protein assays.  To the extent that any information provided to Chiron by
Bioanalysis or UWCM constitutes Proprietary Information, Bioanalysis and UWCM
covenant not to assert any restriction on the use or communication of such
Proprietary Information, including publication, except at the direction of
Chiron. To the extent that any Proprietary Information provided to Chiron by
UWCM or Bioanalysis has entered the public domain, it has done so without the
fault of Chiron.  Bioanalysis has not provided Chiron with Proprietary
Information useful in the field of nucleic acid hybridization assays.

    f.OPTION.  In the event that Bioanalysis obtains during the term of this
Agreement any patent rights either as owner or licensee, which relate to an AE
technology, Bioanalysis will grant to


                                          7

<PAGE> 

Chiron an option to receive a non-exclusive license at a reasonable royalty for
the Licensed Products (as defined to include such patent rights as Licensed
Patents).  The terms of the license will include a most favored licensee clause
and rights to grant sublicenses to third parties with whom Chiron enters into
collaborative arrangements for the development, manufacture and marketing of the
Licensed Products, and will not include license fees or minimum royalties.  The
royalty rate and other terms of the license not specified herein will be
negotiated in good faith and resolved in accordance with the dispute resolution
procedures set forth in Section 9(c) if the parties cannot agree.  The option
will be exercisable no later than six months after Chiron's receipt of
Bioanalysis' written request to either exercise or waive its rights with respect
to a particular patent or patent application.  Bioanalysis agrees that it will
not, without Chiron's written consent, waive its rights to a license under any
of the Patents as defined in the UWCM License.

3.LICENSE FEES AND ROYALTIES

    a.RESTRUCTURING FEE AND ROYALTY ADVANCE.  Chiron shall make the following
non-refundable payments to Bioanalysis on the Closing Date:

         i.A license restructuring fee in the amount of [CONFIDENTIAL TREATMENT
REQUESTED], which shall not be creditable against royalties, and

         ii.An advance upon future royalties in the amount of [CONFIDENTIAL
TREATMENT REQUESTED] (the "Royalty Advance").

         Chiron shall not be required to make any further payments until the
Royalty Advance has been fully depleted by application to royalties earned under
Paragraph 3(d).

    b.BAYER OFFSET ACCOUNT.  An account (the "Bayer Offset Account") shall be
established as an accounting mechanism for the purpose of determining when
Chiron has been fully compensated for its royalty payments under the Bayer
Agreement, plus interest thereon, through reductions in the


                                          8

<PAGE> 

rate of royalty that would otherwise have been payable hereunder.  The amount of
the Bayer Offset Account as of April 1, 1996 is agreed to be [CONFIDENTIAL
TREATMENT REQUESTED].  Effective as of the end of each of Chiron's fiscal
quarters, (i) there shall be added to the Bayer Offset Account (A) an amount
equal to the interest that would have accrued on the balance of the Bayer Offset
Account during such quarter if such balance earned interest at the Prime Rate
(provided that for the quarter ending June 30, 1996, such hypothetical interest
shall be deemed to accrue only from and after the Closing Date) and (B) the
amount of royalties paid by Chiron to Bayer under the Bayer Agreement for such
quarter, and (ii) there shall be subtracted from the Bayer Offset Account an
amount equal to the difference between the amount of royalties paid to
Bioanalysis for such quarter (including royalties paid by means of an
application of credit for the Royalty Advance) and the amount of royalties that
would have been payable at a royalty rate of [CONFIDENTIAL TREATMENT REQUESTED].
Nothing herein shall be construed to require Bioanalysis to make any actual
deposit or payment of funds to cover any amount of the Bayer Offset Account.

    c.ADDITIONAL ROYALTY ACCOUNT.  A second account (the "Additional Royalty
Account") shall be established for the purpose of determining the time at which
the rate of royalty payable hereunder shall be reduced to zero until Chiron has
been fully compensated for its royalty payments under the Bayer Agreement, plus
interest thereon.  The amount of the Additional Royalty Account as of the
Closing Date shall be [CONFIDENTIAL TREATMENT REQUESTED].  Effective as
of the end of each of Chiron's fiscal quarters, (i) there shall be added to the
Additional Royalty Account an amount equal to the interest that would have
accrued on the balance of the Additional Royalty Account during such quarter if
such balance earned interest at the Prime Rate (provided that for the quarter
ending June 30, 1996, such interest shall be deemed to accrue only from and
after the Closing Date and provided further that no such interest shall accrue
after August 7, 2007) and (ii) there shall be subtracted from the Additional
Royalty Account an amount equal  to the amount of royalties paid to Bioanalysis
for such quarter, other than royalties paid through application of the Royalty
Advance.  The Additional Royalty Account is an accounting mechanism only, and
except


                                          9

<PAGE> 

as provided in Section 9(b), nothing herein shall require Chiron to make any
actual deposit of funds to cover the amount of the Additional Royalty Account.

    d.ROYALTY RATES AND APPLICATION OF ADVANCE.  Chiron shall pay Bioanalysis
royalties on its sales of Royalty Products at the rates of (i)[CONFIDENTIAL
TREATMENT REQUESTED].  All royalties shall first be credited against the Royalty
Advance and no additional cash payments in respect of royalties shall be payable
until the Royalty Advance has been fully depleted.  Thereafter, royalties shall
be due and payable as provided in Paragraph 3(d), 3(e) and 4(b).  Chiron will
not be liable to pay more than actual accrued royalties even if they do not
deplete the Additional Royalty Account during the term of this Agreement, and
Bioanalysis will not be responsible for any shortfall if Chiron does not recover
the amount of the Bayer Offset Account during the term hereof.

    e.EFFECT OF INVALIDITY/UNENFORCEABILITY.  Chiron will make all payments
provided for in this Agreement, notwithstanding that any of the Licensed Patents
may be held invalid and/or unenforceable in any proceeding at a later date, so
long as at least one Claim of a Licensed Patent remains in force and has not
been finally adjudicated to be invalid, provided, that (i) after the earlier of
August 7, 2007 or depletion of the Bayer Offset Account, royalties shall be
payable only with respect to Royalty Products as defined in Paragraph 1(q)(ii)
hereof, (ii) no royalties shall be payable after August 7, 2007 except to the
extent, if any, necessary to deplete the Additional Royalty Account; and (iii)
if no Claim of any Campbell Patent remains valid, royalties shall be payable
only with respect to Royalty Products as defined in Clause (B) of Paragraph
1(q)(i).


                                          10

<PAGE> 

4.RECORD KEEPING, PAYMENT AND REPORTS

    a.RECORDS.  Chiron shall maintain records of sales of Royalty Products in
sufficient detail to enable royalties payable hereunder to be determined and
shall cause its Affiliates and sublicensees to do likewise.  Such records shall
be maintained for a period of at least five years after the end of quarter to
which they relate.

    b.REPORTS AND PAYMENTS.  Within sixty (60) days after the end of each
fiscal quarter (as Chiron may establish from time to time for its corporate
operations) Chiron shall provide Bioanalysis with a written statement of Net
Sales Revenue of Royalty Products by Chiron and its Affiliates and sublicensees,
a calculation of royalties owed, and a payment of the total amount then due. 
Quarterly royalty reports will separately identify sales by Chiron and its
sublicensees and will also include a report on the value of the Royalty Advance,
the Additional Royalty Account and the Bayer Offset Account and a report of any
pending disputes under Section 6(b).

    c.PRO-RATION WITHIN QUARTERS.  With respect to changes in royalty rates
occurring other than at the end of a fiscal quarter, the amount of Net Sales
Revenue occurring prior to the change in rate shall be deemed to be equal to the
Net Sales Revenue for the entire quarter, times a fraction, the numerator of
which shall be the number of days from the first day of the quarter to the date
of the rate change and the denominator of which shall be the number of days in
the quarter.

    d.CURRENCY.  All payments hereunder shall be made in U.S. currency.
Non-US$ denominated sales will be converted into dollar sales in accordance with
the standard accounting procedure used by Chiron with respect to its sales
generally as of the Closing Date.  In the event that Chiron changes its method
of converting foreign currency sales into U.S. dollars, Chiron will notify
Bioanalysis of the change.  If during the first accounting period that such
change is in effect, the Net Sales Revenue determined using the new method of
currency conversion is at least 95% of the Net Sales Revenue determined using
the previous method of currency conversion, Bioanalysis'


                                          11

<PAGE> 

approval of the change in conversion method shall not be required.  If the new
method of currency conversion results during such initial accounting period in a
reduction of Net Sales Revenue to less than 95% of Net Sales Revenue under the
previous method, Chiron shall continue to use its previous method of currency
conversion for purposes of this Agreement unless and until Chiron and
Bioanalysis agree on implementation of the new method.  Notwithstanding the
foregoing, non-US dollar sales of sublicensees may be converted to U.S. dollars
in accordance with the method used by the sublicensee in question in its
financial statements generally.

    e.TAXES.  No taxes or deductions of any kind shall be made or taken from
the payments due under Section 3(a).  All taxes which Chiron is required to
withhold from royalty payments shall be deducted from such payments and evidence
of actual payment to the relevant taxing authority shall be delivered to
Bioanalysis at the time the accounting for the payment is made to Bioanalysis. 
The amounts deducted on account of such taxes shall be deemed to have been paid
to Bioanalysis for purposes of depleting the Additional Royalty Account.

    f.AUDIT. Upon Bioanalysis' request (but not more than once per year) and on
reasonable notice, Chiron will, and will cause its Affiliates and sublicensees
to, permit, at the expense of Bioanalysis, independent certified public
accountants, reasonably acceptable to both parties, to have access during
reasonable business hours to inspect and make extracts from such records as may
be reasonably necessary to determine, in respect of any quarterly period, the
correctness of any royalty statements and payments under this Agreement,
provided that Chiron will bear any such reasonable audit expense if the review
or audit shows an underpayment of more than 10% for the applicable period,
unless the conclusions of such review or audit are determined to be incorrect by
agreement of the parties or pursuant to the dispute resolution procedures set
forth in Paragraph  9.  The independent certified public accountants must sign
non-disclosure agreements prohibiting them from revealing any information to any
third party and allowing them to disclose to Bioanalysis only information
reasonably necessary to be communicated in order to carry out the purpose of the
audit.


                                          12

<PAGE> 

5.SUBLICENSES

    a.RIGHT TO GRANT SUBLICENSES.  Chiron shall have the right to grant
sublicenses under the rights granted in Paragraph 2(a) to Affiliates and to
third parties.  Royalties shall be payable to Bioanalysis by Chiron with respect
to its sublicensees' Net Sales Revenue (determined in the same manner as Net
Sales Revenue of Chiron) for Royalty Products at the same rates and in the same
manner as provided in Paragraphs 3(d) and 4(b).  If Chiron does not receive a
royalty report or payment from a sublicensee prior to the date when Chiron's
report and payment are due to Bioanalysis, Chiron shall make the royalty report
and payment to Bioanalysis based on its best estimate of the amount of royalty
due with respect to the sublicense and shall make an appropriate adjustment in
the next quarter's report and payment.  If so agreed by Chiron with a
sublicensee, royalties with respect to a sublicense may be paid semi-annually
rather than quarterly and on the basis of the sublicensee's fiscal periods
rather than Chiron's fiscal periods.

    b.Arrangements Not Sublicenses.  As used herein, the term "sublicense" 
shall not include (i) the right of [CONFIDENTIAL TREATMENT REQUESTED] or a 
[CONFIDENTIAL TREATMENT REQUESTED] or (ii) any arrangement whereby a 
[CONFIDENTIAL TREATMENT REQUESTED], whether or not such party also 
[CONFIDENTIAL TREATMENT REQUESTED] or a combination of Chiron [CONFIDENTIAL] 
TREATMENT REQUESTED]. Chiron's royalty payments to Bioanalysis with respect 
to products [CONFIDENTIAL TREATMENT REQUESTED] who also 
[CONFIDENTIAL TREATMENT REQUESTED] shall be based on the 
[CONFIDENTIAL TREATMENT REQUESTED] by such [CONFIDENTIAL TREATMENT REQUESTED] 
and not on [CONFIDENTIAL TREATMENT REQUESTED].

    c.IN-KIND SUBLICENSES.  In the event that Chiron receives any right
benefit, advantage, concession other than money (including, without limitation
any licenses to any patents of any Affiliate or third party or any business
discount from or any equity of any Affiliate or third party) in consideration
for a grant by Chiron of a sublicense under the licenses granted to it pursuant
to this Agreement, Chiron shall (i) nonetheless be obligated to pay Bioanalysis
royalties pursuant to


                                          13

<PAGE> 

this Agreement based on such third party's or Affiliate's sales or revenues in
connection with Royalty Products or (ii) if no such sales or revenues are to be
received from such third party or Affiliates, inform Bioanalysis of such event
and provide Bioanalysis with all reasonable documentation and information
necessary or appropriate for the parties to negotiate in good faith with respect
to the proper valuation of any such right, benefit, advantage or concession and
the corresponding amounts owing to Bioanalysis in connection therewith, which
shall be determined by allocating the total value received by Chiron between the
sublicense granted hereunder and all other items of value provided by Chiron and
dividing the value allocable to the sublicense granted hereunder equally between
Chiron and Bioanalysis.  In the event that the parties do not agree on the
proper valuation or the amounts owing, such issues will be resolved in
accordance with the parties' dispute resolution procedures pursuant to Section
9.

6.PROSECUTION, MAINTENANCE AND ENFORCEMENT OF PATENTS

    a.PROSECUTION AND MAINTENANCE.  Bioanalysis shall pay for all expenses in
prosecuting the Licensed Patent Applications and maintaining the Licensed
Patents.  Bioanalysis shall maintain the Licensed Patents listed in Schedule B. 
Bioanalysis shall provide Chiron with copies of all pending Licensed Patent
Applications and inform Chiron concerning the progress of all relevant patent
prosecutions on a semi-annual basis.

    b.ENFORCEMENT OF PATENTS BY CHIRON.  Chiron shall have the sole,
unrestricted right to enforce the Licensed Patents against all infringers whose
products would constitute Licensed Products if sold by Chiron hereunder, without
regard to whether the infringing products compete with Chiron's products. 
Chiron shall pay all costs and keep all recoveries with respect to such
enforcement.  Bioanalysis shall assist Chiron as reasonably requested by Chiron,
including by making its officers and employees available as witnesses, and
providing full access to all relevant documents and records, provided that
Chiron shall reimburse all of Bioanalysis out-of-pocket costs


                                          14

<PAGE> 

in connection therewith.  Bioanalysis shall join an enforcement action as party
plaintiff if required by law.  Chiron will have no right to offset against any
payments otherwise due under this Agreement, any costs, expenses or damages
relating to such infringement or infringement litigation.  Chiron agrees to
defend, indemnify and hold Bioanalysis and UWCM harmless from any liability
arising out of actions taken by Chiron pursuant to this sub-section, as well as
attorneys fees arising out of any failure to defend.

    c.ENFORCEMENT BY BIOANALYSIS.  Notwithstanding the provisions of Paragraph
6(b), if Bioanalysis notifies Chiron of activities which Bioanalysis believes
constitute infringement of the Licensed Patents within the scope of Chiron's
right to enforce as specified in Paragraph 6(b), and if Chiron does not within
12 months thereafter commence patent enforcement proceedings against the alleged
infringer or conclude licensing negotiations with the alleged infringer
(provided that such period shall be extended to the extent of any period during
which Chiron is engaged in proceedings against or negotiations with another
infringer), Bioanalysis shall thereafter have the right, but not the obligation,
to enforce the Licensed Patents against such alleged infringer at Bioanalysis'
own expense and with all recoveries of damages being for Bioanalysis' sole
benefit.  Such right of Bioanalysis to enforce the Licensed Patents shall lapse
unless Bioanalysis institutes enforcement proceedings within six months of the
date Bioanalysis is first permitted to institute such proceedings in accordance
with this Paragraph.  Except with respect to enforcement actions against
Ciba-Geigy or its subsidiaries, nothing herein shall be deemed to permit
Bioanalysis to grant any license under the Licensed Patents within the scope of
the exclusive license granted to Chiron hereunder.


                                          15

<PAGE> 

7.REPRESENTATIONS AND WARRANTIES.

    a.Bioanalysis represents and warrants that:

         i.OWNERSHIP.  Bioanalysis is the sole owner of the UWCM License, a
true, complete and correct copy of which, including all amendments through the
date hereof, has been provided to Chiron, and is the sole owner or exclusive
licensee of each of the Licensed Patents and Licensed Patent Applications.

         ii.THIRD PARTY RIGHTS.  Bioanalysis has not granted any rights to any
third party that are inconsistent with the terms of this Agreement, no third
party has made any claim to have been granted such rights, and Bioanalysis is
not aware of any grounds for any such claim.

         iii.COMPLETE LIST.  To the best of Bioanalysis' knowledge after due
inquiry, Schedule B is a complete list of patents and patent applications
relating to Immunoassays using AE labels that is now or at any time since
December 6, 1984 has been legally or beneficially owned or controlled by
Bioanalysis or UWCM, except for Woodhead ET AL. EP 478,626, and the related
applications and counterparts thereof.

         iv.Nothing in this Agreement shall be construed as a warranty or
representation by Bioanalysis as to the validity of any Licensed Patent. 
Nothing in this Agreement shall be construed as a warranty or representation by
Bioanalysis that any product made, used, sold or imported under any Licensed
Patent is or will be free from infringement of patents not licensed hereunder or
patents of third parties.  Nothing in this Agreement shall be construed as
conferring by implication, estoppel or otherwise any license or rights under any
patents belonging to Bioanalysis other than the Licensed Patents as defined in
this Agreement.


                                          16

<PAGE> 

    b.Chiron represents and warrants that Net Sales Revenue for the period
January 1, 1995 - December 31, 1995 was not less than [CONFIDENTIAL TREATMENT
REQUESTED].

8.TERM AND TERMINATION

    a.TERM.  Except as provided in Paragraph 8(b), the licenses granted to
Chiron hereunder shall continue until the expiration of the last to expire of
the Licensed Patents.  Notwithstanding the foregoing, Chiron's obligations to
pay royalties hereunder shall continue only so long as provided in accordance
with Paragraphs 3(d) and 3(e).

    b.CHALLENGE TO VALIDITY.  The initiation of any legal proceeding
challenging the validity of a Campbell Patent by Chiron or any party acting
under the direction and control of Chiron shall give Bioanalysis an immediate
right to terminate the license upon written notice to Chiron, such termination
to be effective thirty (30) days after notice of termination unless such
challenge to validity is dismissed with prejudice within the thirty day period. 
Notwithstanding the foregoing, if the challenge to validity is asserted by a
party other than Chiron or an Affiliate and Chiron disputes whether such party
is under its direction and control, no termination shall occur unless a final
decision of an arbitral panel in a proceeding conducted in accordance with
Paragraph 9 hereof determines that such party is under the direction and control
of Chiron.  If the arbitrators determine that the party challenging validity was
acting under the direction or control of Chiron, Chiron will have a period of
thirty (30) days to cause such challenge to be withdrawn and thereby avoid
termination, unless the arbitrators conclude that Chiron's contention as to
direction or control was made in bad faith, in which case the Agreement shall
terminate immediately upon such determination.  Nothing herein shall prevent
Chiron from presenting evidence of prior art in connection with a dispute
regarding the proper interpretation of the scope of any Claim of any patent.


                                          17

<PAGE> 

9.DISPUTES AND REMEDIES FOR BREACH.

    a.DAMAGES SOLE REMEDY.  Except as provided in paragraphs 8(b) and 9(b),
Bioanalysis' sole remedy for breach of the license agreement by Chiron shall be
the recovery of an award of damages in an arbitration proceeding, which award
shall include interest at the Prime Rate compounded quarterly from the date the
damages were incurred.  In any arbitration proceeding, the arbitrators shall
have authority to award attorneys' fees to the prevailing party.  Nothing herein
is intended to limit Bioanalysis right to seek injunctive relief with respect to
infringement of the Licensed Patents by activities outside the scope of the
license and sublicense granted hereunder.

    b.EXTRAORDINARY REMEDY.  If Bioanalysis, after initiating and prevailing in
an arbitration with respect to non-payment of royalties in which the recovery
exceeds 10% of the amount of royalties due for the period with respect to which
the determination of royalties is in dispute (which period shall be a period of
at least two quarters), again initiates and prevails in such an arbitration and
recovers such an amount, and provided that Chiron has not theretofore been the
prevailing party in an arbitration between the parties, the unrecovered balance,
if any, of the Additional Royalty Account shall become immediately due and
payable as a non-refundable advance on future royalties.

    c.RESOLUTION OF DISPUTES.  Chiron and Bioanalysis agree that the following
procedure will govern the resolution of any dispute between or among them
arising out of or relating to this Agreement: 

         i.the parties will use all reasonable efforts for a period of at least
90 days to resolve the dispute through negotiation; 

         ii.if the dispute cannot be settled through negotiation, Chiron and
Bioanalysis agree to try in good faith to settle the dispute by mediation
administered by the American Arbitration Association under its Commercial
Mediation Rules; and

                                          18

<PAGE> 



         iii.if the dispute cannot be resolved by mediation Chiron and
Bioanalysis agree that the dispute will be resolved by mandatory, binding
arbitration. The arbitration will take place in San Francisco, CA, at the
offices of the American Arbitration Association ("AAA"), pursuant to the AAA
International Commercial Rules. The dispute will be resolved by the majority
decision of three arbitrators of whom one will be nominated by the Claimant(s)
and one by Respondent(s), and a third nominated by the two party-appointed
arbitrators, unless Claimant(s) and Respondent(s) agree in any given dispute to
have it settled by a single arbitrator acceptable to both Claimant(s) and
Respondent(s). If a party fails to nominate its arbitrator to a three arbitrator
panel within 30 days after the other party has appointed its arbitrators and
served written notice of such appointment on the other party, or if within 30
days after both party-appointed arbitrators are appointed, the party appointed
arbitrators have not agreed upon the appointment of a third arbitrator, then the
missing arbitrator will be appointed by the AAA in accordance with the governing
rules.   The decision of the arbitrators, or of the single arbitrator, as the
case may be, will be final and binding.  Judgment on the award may be entered in
any Court of competent jurisdiction.

         iv.The parties agree that, prior to the formation of the arbitral
panel, a party may apply to a state or federal court in California for
provisional or interim relief.  After the arbitration panel is empaneled, it
shall have sole jurisdiction to hear such application, except that the parties
agree that any relief ordered by the arbitrators may be enforced by a California
state court.

         v.If Chiron or Bioanalysis desire to join Gen-Probe as a party to an
arbitration commenced or to be commenced under this Section, then each of the
parties shall use their best efforts to convince Gen-Probe to join the
arbitration.  If Gen-Probe will not agree to join the arbitration, then each of
Chiron and Bioanalysis agrees that, notwithstanding this Section, the
complaining party shall bring its dispute in federal court in California, or in
the event that the federal court does not have jurisdiction over the subject
matter of the dispute, in state court in California.

         vi.Each of the parties submits to the jurisdiction of the federal
courts in California, or in the event that the federal court does not have
jurisdiction over the subject matter of the


                                          19

<PAGE> 

dispute, to the jurisdiction of the state courts in California, for purposes of
Section 9(c)(iv) and 9(c)(v) of this Agreement.

10.NOTICES.

    Any notice or report required or permitted to be given under this Agreement
shall be in writing and shall be delivered by hand or overnight courier or
mailed postage prepaid by recorded, registered or certified mail return receipt
requested, addressed as set forth below unless changed by notice so given:

         If to Chiron:

              Ciba Corning Diagnostics Corp.
              333 Coney Street
              East Walpole, MA  02032

              Attention:  President
              Copy to:  General Counsel

         If to Bioanalysis:

              Bioanalysis Limited
              Cardiff Business Technology Centre
              Senghenydd Road
              Cardiff CF2 4AY, United Kingdom

              Attention:  Managing Director

    Any such notice or report shall be deemed delivered on the date received,
provided that no such notice or report shall be deemed delinquent if deposited
in the mails or delivered to a courier service on or before the date such notice
or report is required to be given.


                                          20

<PAGE> 

11.MISCELLANEOUS.

    a.CONFIDENTIALITY.  Bioanalysis agrees to hold in confidence all
information it may receive hereunder concerning royalty payments and sales by
Chiron and its Affiliates and sublicensees, except that Bioanalysis may disclose
such information (i) to the extent such information has previously been publicly
disclosed by Chiron, (ii) to the extent required to be disclosed by applicable
law and after using all reasonable efforts to obtain confidential treatment of
the required disclosure, (iii) to its legal counsel and accountants, or (iv) to
the arbitrators in any arbitral proceeding pursuant to Paragraph  9 hereof. 
This obligation shall survive termination of this Agreement.

    b.NO JOINT VENTURE.  This Agreement does not constitute and shall not be
construed as an agency, joint venture or partnership between the parties.

    c.BENEFIT AND ASSIGNMENT.  This Agreement shall be binding upon and inure
to the benefit of the successors and assigns of the parties hereto, provided,
however, that neither party may assign or transfer its rights and obligations
without the written consent of the other party, which consent shall not be
unreasonably withheld, except that Chiron may assign its rights and obligations
without such consent to a purchaser or other transferee of Chiron's
immunodiagnostics business, and Bioanalysis may assign its rights and
obligations without such consent to UWCM  and Affiliates of Bioanalysis.

    d.ENTIRE AGREEMENT; AMENDMENT.  This Agreement is the entire agreement
between the parties with respect to the matters set forth herein and supersedes
all other prior agreements or understandings, whether written or oral.  No
representations, oral or otherwise, express or implied, other than those
expressly set forth herein or in the Settlement Agreement have been made by
either party to the other concerning the subject matter of this Agreement.  This
Agreement may not be


                                          21

<PAGE>

modified or amended  other than in writing signed by the party whose rights or
obligations are modified or amended.

    e.WAIVER.  The failure of party to insist upon another party's strict
adherence to any term of this Agreement on any occasion will not be construed as
a waiver or deprive that party of the right to insist upon strict adherence to
that term or any other term of this Agreement.

    f.GOVERNING LAW.  This Agreement shall be governed and construed in
accordance with the laws of the State of California, U.S.A., without giving
effect to that state's conflict of law rules.

    g.SEVERABILITY.  If any provision or sub-provision of this Agreement is
found invalid or unenforceable, the balance of the Agreement, and all provisions
thereof shall continue in full force and effect.

    h.INTERPRETATION.  References to any gender include the other gender and to
the singular number the plural number and vice versa.  All headings throughout
this Agreement have been inserted for the purpose of ease of reference  only and
do not define, limit or affect the meaning or interpretation of this Agreement
or of any instrument created pursuant hereto or in accordance herewith.  Each
party has been provided with an opportunity to participate in the drafting and
preparation of this Agreement.  Therefore, in any construction to be made of
this Agreement, the same shall not be construed against any party.

    i.GEN-PROBE AGREEMENT - This Agreement does not diminish, alter, or affect
in any way, the rights of Gen-Probe under the Gen-Probe Agreement.

                   [REMAINDER OF THE PAGE LEFT INTENTIONALLY BLANK]


                                          22

<PAGE>

    IN WITNESS WHEREOF, the parties hereto have executed this Agreement or
caused their duly authorized representatives to execute this Agreement as of the
date first above written.

CIBA CORNING DIAGNOSTICS CORP.         BIOANALYSIS LIMITED

By: /s/ Kenneth J. Conway             By: /s/ J.L.D. Bell
    --------------------------            ----------------------------
    Kenneth J. Conway                     Director
    Senior Vice President, 
    Immuno/Chemistry


Date: 7/2/96                          Date:
     -------------------------

                                      21


<PAGE> 

                                                                      SCHEDULE A
                                                                     PAGE 1 OF 8

                                      SCHEDULE A

                                 BIOANALYSIS PRODUCTS


1.  HIV 1/2 per attached description (and all reasonable improvements thereto
which do not substantially change the nature of the product).

2.  Hepatitis B per attached description (and all reasonable improvements
thereto which do not substantially change the nature of the product).

3.  Anti-Thyroglobulin per attached description (and all reasonable
improvements thereto which do not substantially change the nature of the
product).

4.  Anti-Thyroid Peroxidase per attached description (and all reasonable
improvements thereto which do not substantially change the nature of the
product).

5.  Thyrotrophin Receptor Antibodies per attached description (and all
reasonable improvements thereto which do not substantially change the nature of
the product).

6.  Insulin (manual microtiter plate format).

7.  Proinsulin (manual microtiter plate format).

Reasonable improvements do not include modifications to enable use on automated
instruments.


                                          1

<PAGE>

                                                                    SCHEDULE  A
                                                                      Page ____

                  IMMUNOASSAY FOR HIV  1/2  ANTIBODIES IN SERUM


BACKGROUND


HIV is regarded as the causative agent of AIDS.  It is difficult to detect
circulating viral protein or cDNA/RNA by routine methods.  Thus screening tests
for HIV rely on the detection of circulating (anti-HIV) antibodies.

Since the discovery of HIV, a number of such assays have been described.  
There are three main HIV antigenic gene products:  GAG (viral core proteins:  
p55, p24, p17, p9, p7), POL (regulatory proteins including reverse 
transcriptase p66 and p51, protease p10, integrase/endonuclease p31) and ENV 
(envelope glycoproteins gp160, gp120 and gp41).  Of these, the gene products 
of ENV and GAG are of most interest with regard to the detection of anti-HIV 
antibodies in serum.  All these proteins and their fragments are capable of 
generating a host immune response and will yield positive bands in western 
blot and radioimmuno-precipitation detection systems.  These two testing 
methods offer high levels of specificity and sensitivity but are too labor 
intensive and time consuming for routine laboratory use.  They thus form a 
body of confirmatory tests for samples screened positive for HIV antibodies 
by ELISA.

Early tests used viral lysates as antigen though this invariably resulted in an
unacceptably high false positive rate.  More recently developed tests have
involved the use of synthetic or recombinant proteins as antigen to minimize
unwanted cross-reactions.

This report describes a method for the detection of [Confidential Treatment
Requested] to HIV1 and HIV2 by the use of [Confidential Treatment Requested] and
[Confidential Treatment Requested] respectively.


METHOD

[Confidential Treatment Requested] are dissolved in [Confidential Treatment
Requested] buffer to give a concentration of [Confidential Treatment Requested]
and added to the wells of [Confidential Treatment Requested] or [Confidential
Treatment Requested].  Following [Confidential Treatment Requested] incubation,
wells are [Confidential Treatment Requested] by addition of [Confidential
Treatment Requested] in [Confidential Treatment Requested].  This is followed by
a further incubation for [Confidential Treatment Requested] at [Confidential
Treatment Requested].  Affinity purified [Confidential Treatment Requested] is
labeled with [Confidential Treatment Requested] by standard techniques and
diluted in [Confidential Treatment Requested] buffered [Confidential Treatment
Requested] containing [Confidential Treatment Requested] treated [Confidential
Treatment Requested] and [Confidential Treatment Requested].  [Confidential
Treatment Requested] of this solution yields approximately [Confidential


<PAGE>

Treatment Requested].  Pooled HIV1 positive serum was obtained from
[Confidential Treatment Requested].  HIV2 positive serum and HIV1 seroconversion
panels were obtained from [Confidential Treatment Requested].  Control samples
were obtained from the [Confidential Treatment Requested] and [Confidential
Treatment Requested].

Sample diluent is [Confidential Treatment Requested] containing [Confidential
Treatment Requested] and [Confidential Treatment Requested].


ASSAY PROTOCOL

1.  Pipette [Confidential Treatment Requested] sample diluent into each well

2.  Add [Confidential Treatment Requested] sample or control

3.  Mix by addition of a further [Confidential Treatment Requested] sample
    diluent

4.  Incubate [Confidential Treatment Requested] at [Confidential Treatment
    Requested] with [Confidential Treatment Requested]

5.  Wash [Confidential Treatment Requested] in [Confidential Treatment
    Requested]

6.  Add [Confidential Treatment Requested] labeled antibody

7.  Incubate [Confidential Treatment Requested] with [Confidential Treatment
    Requested]

8.  Wash [Confidential Treatment Requested] in [Confidential Treatment
    Requested]

9.  Read each well for [Confidential Treatment Requested] in plate luminometer


<PAGE>

                 SCREENING TEST FOR HEPATITIS B SURFACE ANTIGEN


INTRODUCTION

Hepatitis B represents a significant global health problem.  Because of its 
mode of transmission through biological fluids, it is of particular concern 
to the blood transfusion services since the disease will invariably affect 
those who receive infected blood.

The cause of infection is the hepatitis B virus (HBV) which, in its intact form
is known as a Dane particle.  This particle is of 42 nm diameter, though
infected blood may contain large quantities of viral envelopes as 22 nm spheres
or as filaments.  These particles incorporate the hepatitis B surface antigen
(HBSAg) which is a specific marker of HBV infection.  HBSAg comprises a group
determinant and two sets of mutually exclusive sub-type determinants which
produce the sub-types adw, adr, ayw and ayr.

Detection of the presence of immunoreactive HBSAg in serum or plasma is
diagnostic of HBV infection.


METHOD

The method described below is a [Confidential Treatment Requested] assay in
which the solid-phase antibody comprises a mixture of [Confidential Treatment
Requested] and [Confidential Treatment Requested] antibodies [Confidential
Treatment Requested] to the wells of microtitre strips or plates and the labeled
reagent is a mixture of [Confidential Treatment Requested] incorporating a
[Confidential Treatment Requested].  The serum sample is incubated in a well
together with an aliquot of [Confidential Treatment Requested] and after
reaction, the wells are washed to remove unbound material.  The plate carrying
the wells is transferred to a [Confidential Treatment Requested] to detect the
presence of bound immune complexes.  Results are analyzed by comparison with
test wells containing samples of positive and negative controls.


DESCRIPTION

Microtitre plates or strips [Confidential Treatment Requested] are coated with a
mixture of [Confidential Treatment Requested] and [Confidential Treatment
Requested] antibody.  Coating is carried out by [Confidential Treatment
Requested] by [Confidential Treatment Requested] reaction in [Confidential
Treatment Requested].  After washing with [Confidential Treatment Requested] the
plates are blocked with [Confidential Treatment Requested] for [Confidential
Treatment Requested] hours at [Confidential Treatment Requested].  The plates
are washed again and then vacuum dried prior to storage in sealed bags.


<PAGE>

Two [Confidential Treatment Requested] antibodies are labeled with [Confidential
Treatment Requested] by standard methods and are used in solution in
[Confidential Treatment Requested] supplemented with [Confidential Treatment
Requested] and [Confidential Treatment Requested].  Approximately [Confidential
Treatment Requested] are added to each well in a volume of [Confidential
Treatment Requested].


PROTOCOL

1.  Dispense [Confidential Treatment Requested] test sample or control into
    each well

2.  Add [Confidential Treatment Requested] labeled antibody and cover plate

3.  Incubate at [Confidential Treatment Requested] for [Confidential Treatment
    Requested] with shaking

4.  Wash plate [Confidential Treatment Requested] with [Confidential Treatment
    Requested]

5.  Transfer plate to [Confidential Treatment Requested] and read each well for
    [Confidential Treatment Requested].


<PAGE>

                       IMMUNOCHEMILUMINOMETRIC ASSAY FOR
                            THYROGLOBULN ANTIBODIES


INTRODUCTION

Autoimmune thyroid disease is characterized by the production of antibodies to
various thyroid proteins.  Thyroglobulin (Tg) is one such protein and the
detection of circulating antibodies to Tg is indicative of autoimmunity.


METHOD

The present assay for Tg antibodies involves [Confidential Treatment Requested]
of Tg onto [Confidential Treatment Requested] tubes to which the serum sample is
added.  Following [Confidential Treatment Requested] and washing, anti-Tg
antibodies, if present, are detected using [Confidential Treatment Requested]
labeled [Confidential Treatment Requested] which binds to the human
Immunoglobulin.


DESCRIPTION

[Confidential Treatment Requested] tubes are coated with [Confidential Treatment
Requested] using standard conditions.  [Confidential Treatment Requested] is
labeled with [Confidential Treatment Requested] in the usual manner.

Purified Tg is labeled with [Confidential Treatment Requested] Co.) according to
the Manufacturer's instructions.

The test is designed to be used with a [Confidential Treatment Requested] serum
sample.

PROTOCOL

    1.   Dispense [Confidential Treatment Requested] of sample into
         [Confidential Treatment Requested] coated tube
    2.   Add [Confidential Treatment Requested] solution and vortex
    3.   Incubate for [Confidential Treatment Requested]
    4.   Aspirate and wash [Confidential Treatment Requested] with wash
         solution
    5.   Add [Confidential Treatment Requested] of [Confidential Treatment
         Requested] solution
    6.   Incubate for [Confidential Treatment Requested]
    7.   Aspirate and wash [Confidential Treatment Requested]
    8.   Measure tubes for [Confidential Treatment Requested] in [Confidential
         Treatment Requested]


<PAGE>

PERFORMANCE

Limit of detection: [Confidential Treatment Requested] TgAb activity
Precision:          [Confidential Treatment Requested] CV intra-assay over range
Range:              [Confidential Treatment Requested] U/ml



                        IMMUNOCHEMILUMINOMETRIC ASSAY FOR
                          THYROID PEROXIDASE ANTIBODIES


INTRODUCTION

Autoimmune thyroid disease is characterized by the production of antibodies to
various thyroid proteins.  Thyroid peroxidase (TPO) is one such protein and the
detection of circulating antibodies to TPO is indicative of thyroid
autoimmunity.


METHOD

The present assay for TPO antibodies involves indirect [Confidential Treatment
Requested] of TPO onto [Confidential Treatment Requested] tubes to which the
serum sample is added.  Following aspiration and washing, anti-TPO antibodies,
if present, are detected using [Confidential Treatment Requested] labelled
[Confidential Treatment Requested] which binds to the human immunoglobulin.


DESCRIPTION

[Confidential Treatment Requested] tubes are coated with [Confidential Treatment
Requested] using standard conditions.  [Confidential Treatment Requested] is
labeled with [Confidential Treatment Requested] in the usual manner.

Purified TPO is labeled with [Confidential Treatment Requested] Co.) according
to the Manufacturer's instructions.

The test is designed to be used with a [Confidential Treatment Requested] serum
sample.


<PAGE>

PROTOCOL

    1.   Dispense [Confidential Treatment Requested] of sample into
         [Confidential Treatment Requested] coated tube
    2.   Add [Confidential Treatment Requested] of [Confidential Treatment
         Requested] solution and vortex
    3.   Incubate for [Confidential Treatment Requested] at [Confidential
         Treatment Requested]
    4.   Aspirate and wash [Confidential Treatment Requested] with wash
         solution
    5.   Add [Confidential Treatment Requested] of [Confidential Treatment
         Requested] solution
    6.   Incubate for [Confidential Treatment Requested] at [Confidential
         Treatment Requested]
    7.   Aspirate and wash [Confidential Treatment Requested] times
    8.   Measure tubes for [Confidential Treatment Requested] in [Confidential
         Treatment Requested]

PERFORMANCE

Limit of detection: [Confidential Treatment Requested]
Precision:          [Confidential Treatment Requested] CV intra-assay over range
Range:              [Confidential Treatment Requested] U/ml



                         CHEMILUMINESCENT RECEPTOR ASSAY FOR
                           THYROTROPHIN RECEPTOR ANTIBODIES



INTRODUCTION

Autoimmune thyroid disease is characterized by the production of antibodies to
various thyroid proteins.  Thyrotrophin receptor (TR) is one such protein and
the detection of circulating antibodies to TR is important in the diagnosis and
management of autoimmune hyperthyroidism (Graves' Disease).


METHOD

The present assay for TR antibodies (TRAb) involves incubation of the serum
sample with a [Confidential Treatment Requested] preparation in the presence of
[Confidential Treatment Requested] labeled[Confidential Treatment Requested]. 
The presence of TRAb prevents binding of the labeled [Confidential Treatment
Requested] to the 


<PAGE>

receptor.  Receptor-bound [Confidential Treatment Requested]activity is thus 
[Confidential Treatment Requested] to TRAb activity.  Receptor-bound 
complexes are separated by [Confidential Treatment Requested]precipitation.


DESCRIPTION

[Confidential Treatment Requested] tubes are used as reaction tubes.

[Confidential Treatment Requested] is labeled with [Confidential Treatment
Requested] using established methods.

[Confidential Treatment Requested] receptors are isolated from [Confidential
Treatment Requested] using published methods.

The test is designed to be used with a [Confidential Treatment Requested] serum
sample.


PROTOCOL

    1)   Dispense [Confidential Treatment Requested] of serum sample into tube
    2)   Add [Confidential Treatment Requested] of receptor solution
    3)   Incubate [Confidential Treatment Requested] at [Confidential Treatment
         Requested]
    4)   Add [Confidential Treatment Requested] of [Confidential Treatment
         Requested] labeled [Confidential Treatment Requested] solution
    5)   Incubate [Confidential Treatment Requested]
    6)   Add [Confidential Treatment Requested] solution, vortex
    7)   Centrifuge for [Confidential Treatment Requested] at [Confidential
         Treatment Requested]
    8).  Aspirate supernatant
    9)   Resuspend pellet in [Confidential Treatment Requested] deionized water
    10)  Measure tubes for [Confidential Treatment Requested] in [Confidential
         Treatment Requested]


PERFORMANCE

Limit of detection:   [Confidential Treatment Requested] TRAb activity
Precision:            [Confidential Treatment Requested] intra-assay over range
Range:                [Confidential Treatment Requested] U/ml


<PAGE>

                                                                     SCHEDULE  B
                                                                        Page ___


                                  SCHEDULE  B
                                           
                                  UWCM PATENTS
                                           


CASE WCM 3:  LUMINESCENT PROTEIN LABELING

COUNTRY             PATENT #          FILED          PRIORITY        EXPIRY
- -------             --------          -----          --------        ------

GB                  2008247B          14/11/78       17/11/77        14/11/98
Canada              1113392           16/11/78       17/11/77        01/12/98
Germany             2849708           16/11/78       17/11/77        Lapsed
Switzerland         640061            13/11/78       17/11/77        13/11/98
France              7832459           17/11/78       17/11/77        17/11/98
USA                 4478817           14/11/78       17/11/77        23/10/01


CASE WCM 3 (DIVISIONAL) HOMOGENEOUS ASSAY

COUNTRY             PATENT #          FILED          PRIORITY        EXPIRY
- -------             --------          -----          --------        ------

GB                  2095830B          01/11/81       17/11/77        14/11/98
Germany             2858792           07/06/89       17/11/77        17/11/98
Switzerland         645725            13/12/83       17/11/77        13/11/98
Canada              1116079           27/3/81        17/11/77        12/01/99


CASE WCM 13:  ACRIDINIUM LABELS

COUNTRY             PATENT #          FILED          PRIORITY        EXPIRY
- -------             --------          -----          --------        ------

GB                  2112779B          08/12/82       11/12/81        08/12/02
Europe*             0082636           08/12/82       11/12/81        08/12/02
USA#                4946958           26/09/88       11/12/81        07/08/07


CASE WCM 16:  MASS PHOTON IMMUNOASSAY

COUNTRY             PATENT #          FILED          PRIORITY        EXPIRY
- -------             --------          -----          --------        ------

GB                  2129553B          09/09/83       10/09/82        09/09/03
Europe**            0103469           09/09/83       10/09/82        09/09/03


<PAGE>

USA                 4761382           05/02/87       10/09/82        02/08/05
Japan               Pending           29/12/83       10/09/82        29/12/03

*France, Germany, Holland, Switzerland

**Belgium, France, Germany, Italy, Holland, Switzerland

                            UWCM PATENT APPLICATIONS
                                           
#US Continuation Applications 08/328563 filed 24/10/94 and 08/455414 filed
31/05/95 are still pending.


                              BIOANALYSIS PATENTS
                                      None
                                        
                        BIOANALYSIS PATENT APPLICATIONS
                                      None
                                           




<PAGE>

C H I R O N




May 6, 1996                                                       CONFIDENTIAL
                                                                  ------------

Magnus Lundberg
Gullvivivevagen #5
75655 Uppsala, Sweden

Dear Magnus:

We are pleased to confirm our offer of employment as Vice President, Chiron 
Corporation, reporting to me.  Your starting salary will be paid at a monthly 
rate of $14,583 ($175,000 annually) as an exempt employee.  The details of 
your Employment Contract will be outlined at a later date.

You will be eligible to participate in our Stock Option Program. Subject to 
the approval of the Board of Directors, you will be awarded a stock option 
grant of 7,500 shares.  We expect that the grant will be approved and 
effective within 90 days of your employment date.  The exercise price of the 
option will be set at the actual market price of a share of stock on the date 
the grant is approved.  Under the option program as it is currently 
administered, you will be eligible for additional annual stock option grants 
based on your performance.

You will be eligible to participate in Chiron's Executive Variable 
Compensation Plan, which as structured, is paid out in the first quarter of 
each calendar year based upon company and individual performance in the 
preceding year.  Your first payout will be made in the first quarter of 1997. 
The payout potential for your position under the current program will be a 
maximum of 60% of your annual salary.  You will be guaranteed a minimum of 
30% for the first two years of employment.  Additionally, you will be 
provided a company car of a value up to $33,000 for your use during your stay 
in the Bay Area.

The following are highlights of your Chiron benefits.  Some are effective 
immediately upon your employment, while there are established enrollment 
periods for others.  Your group medical insurance benefits start on the first 
day of the month following your date of hire.

     1.  A choice of medical and dental coverage for you and your eligible
         dependents.

     2.  Three weeks paid vacation per year.


CHIRON CORPORATION - 4560 Horton Street - Emeryville, CA - 94608-2916 - 
510-655-8730

<PAGE>

Magnus Lundberg
May 6,1996
Page 2

     3.  Eight scheduled and two floating paid holidays per year.

     4.  Eligible employees (20 hours or more per week) accrue 10 days of
         sick leave per calendar year.

     5.  401(k) tax-deferred investment plan.

     6.  Employee stock purchase plan.

     7.  Tuition reimbursement program.

     8.  Disability salary continuation plan.

     9.  Life and accidental death/dismemberment insurance.

A member of the Human Resources Department staff will assist you with all 
aspects of your temporary relocation to the San Francisco Bay Area.  Chiron 
provides a relocation package for you which will cover the following items:

     *   One house-hunting trip to the San Francisco Bay Area for you and
         your family. Travel arrangements and tickets must be secured through 
         the Chiron Travel Department.

     *   Relocation counseling assistance.

     *   Movement of your household goods to the San Francisco Bay Area.

     *   Storage of household goods for up to 120 days.

     *   A housing allowance for your stay in the San Francisco Bay Area.

     *   Travel to the San Francisco Bay Area for you and your family so
         that you may start work on a date that is yet to be determined. 
         Travel arrangements and tickets must be secured through the Chiron
         Travel Department.

As part of Chiron's medical surveillance program, you will be required to 
provide a baseline blood draw.

This offer is contingent upon your ability as required by federal law, to 
establish your employment eligibility as a U.S. citizen, a U.S. lawful 
permanent resident, or an individual specifically authorized for employment 
in the U.S. by the Immigration and Naturalization Service.  Please read the 
enclosed notice specifying the documentation required in this

<PAGE>


Magnus Lundberg
May 6, 1996
Page 3

regard.  If you have an employment authorization document (EAD) issued by the 
Immigration & Naturalization Service, please contact Rick Ross at 
(510) 601-2511. This allows us to ensure that your authorized employment will 
not lapse during your period of employment with Chiron.  If possible, we request
that you present your Social Security card to Human Resources for the purpose 
of verifying that your payroll records are accurately recorded.

Magnus, we hope the terms of this offer are satisfactory and we look forward to
a favorable response.  If you have questions in the meantime, feel free to 
call me.

Sincerely,

CHIRON CORPORATION


/s/ Edward E. Penhoet

Edward E. Penhoet, Ph.D.
President and Chief Executive Officer

Enclosure

cc:  Human Resources

<PAGE>




May 25, 1996



Magnus Lundberg
Gullvivivevagen #5
75655 Uppsala, Sweden


Dear Magnus:

      This letter confirms the exchange of correspondance and conversations 
we've had regarding the terms of your employment.

      We reaffirm our commitment to pay reasonable costs for moving you and 
your immediate family, along with your household goods, to the San Francisco 
Bay Area at a specific date this fall. Further, Chiron will absorb all 
reasonable costs associated with moving your family and household goods back 
to Sweden approximately one year later.

      Your offer of employment is contingent upon your ability to establish 
employment eligibility in the United States. In that regard, Chiron's Legal 
and Human Resources departments will be at your disposal in handling these 
matters.

      I confirm that you will receive four weeks' vacation per calendar year.

      With respect to notice of termination, either you or Chiron can give 
notice of termination. Said termination would take place six months from the 
written notification. Your employment and salary would continue up to that 
termination date. You would be entitled to severance pay equivalent to one 
year's salary and benefits, including the six month notice period.

      We will provide you with financial assistance in the renting of a home 
in the San Francisco area in the form of a monthly contribution not to exceed 
$2,000.


Sincerely,


Edward E. Penhoet
President and Chief Executive Officer



<PAGE>

                                                                  Exhibit 10.86

                         [CONFIDENTIAL TREATMENT REQUESTED]

[Certain confidential information has been omitted from the Agreement and filed
separately with the Securities and Exchange Commission pursuant to a request by
Registrant for confidential treatment pursuant to Rule 24b-2.  The omitted
confidential information has been identified by the following statement:
"CONFIDENTIAL TREATMENT REQUESTED".]

Notarial Deed A. Prot. 1996/20
dated 17 February 1996 of the
Notary Public Dr. Werner Wenger, Basle


                                    NOTARIAL DEED
                        -------------------------------------
                          PURCHASE AND ASSIGNMENT AGREEMENT

Negotiated in Basle, Switzerland on the 17th day of February 1996.

Before the notary public Dr. Werner Wenger with place of office in Basle
appeared today:

1.   MR. BERND CROMME, born 8 August 1939, attorney-at-law, of German
     nationality, domiciled at D-65812 Bad Soden,

2.   DR. HANS KUPPER, born 17 July 1944, bio-chemist, of German nationality,
     domiciled at D-35039 Marburg,

     both acting not for themselves, but with a power of attorney for
     BEHRINGWERKE AG, with an office at Marburg (Lahn), registered at the
     commercial register of Marburg (Lahn) under HR B 1055, with notarial
     confirmation of representation, an authenticated copy of which constitutes
     APPENDIX A to this document;

3.   DR. EKKEHARD MOESER, born 20 July 1947, attorney-at-law, domiciled at
     D-60389 Frankfurt am Main, not acting for himself but

     a)   with a power of attorney for 31, CORSA VERWALTUNGSGESELLSCHAFT MBH,
          with an office at Frankfurt am Main, with notarial confirmation of
          representation, the original of which constitutes APPENDIX B to this
          document;


<PAGE>


                                          2


     b)   with a power of attorney for CHIRON CORPORATION, with an office at
          California, with notarial confirmation of representation, the original
          of which constitutes APPENDIX C to this document.

The foregoing persons identified themselves to the notary public by presenting
valid official national identity cards or passports.

Such persons and the notary public declared that they all have sufficient
knowledge of the English language to follow the notarization, which, at the
request of all the parties, will be conducted in English.

Such persons confirmed that they do not wish this document to be translated into
the German language nor do they wish that a German translation of this document
be added as an annex to this document.

From a conversation with such persons, the notary public took evidence that each
of them has sufficient command of the English language to follow and to
understand the document here notarized.

The foregoing persons request that the notary public notarize the following:


<PAGE>

                                          3


                          PURCHASE AND ASSIGNMENT AGREEMENT

between

Behringwerke Aktiengesellschaft,
(hereinafter "Behringwerke")
                                                          - ON THE ONE SIDE -

AND

(1)  31. CORSA Verwaltungsgesellschaft mbH,

     (to be renamed "Chiron Biocine GmbH")

     (hereinafter "Buyer")


(2)  Chiron Corporation,

     (hereinafter "Guarantor")

                                                          - ON THE OTHER SIDE -.

(Behringwerke and Buyer are collectively hereinafter referred to as the
"Parties" or individually as the "Party", as the context requires.)


<PAGE>

                                          4


TABLE OF CONTENTS


Directory of Annexes                                                         5

Preamble                                                                     6

1.   Facts; Covenants                                                        6

2.   Sale and Assignment                                                     7

3.   Put and Call; Shareholders' Agreement                                   8

4.   Purchase Price                                                          9

5.   Condition Precedent                                                    12

6.   Operating Lease Agreement                                              13

7.   Behringwerke's Representation and Warranties                           14

8.   Use of Name                                                            20

9.   Buyer's Representation and Warranties                                  21

10.  Cooperation after the Closing Date                                     22

11.  Non-Competition                                                        22

12.  Confidentiality                                                        23

13.  Merger Control                                                         23

14.  Indemnification; Guarantee                                             24

15.  Miscellaneous                                                          24


<PAGE>

                                          5


DIRECTORY OF ANNEXES

Annex 1.4 (a)    -    Contribution Agreement

Annex 1.4 (b)    -    Partnership Agreement

Annex 3.4        -    Shareholders' Agreement

Annex 4.6        -    Investment Plan for 1996

Annex 4.7        -    Terms and Conditions for Commission

Annex 7.1.16     -    Third Party Consents Agreements

Annex 7.1.18     -    Liens, Pledges, Usufructs and other Encumbrances

Annex 7.1.19     -    Financial Statements

Annex 8          -    Use of Name and Logo

Annex 11         -    Hoechst Letter


<PAGE>

                                          6


PREAMBLE

A.   Object of Behringwerke, a stock company (AKTIENGESELLSCHAFT) incorporated
     under the laws of Germany, is, inter alia, the production and distribution
     of pharmaceutical products for human and animal use.

B.   Object of Buyer, a GmbH organized under the laws of Germany, is the
     distribution of pharmaceutical products for human use.

C.   The Parties propose to enter into a joint venture in the field of human
     vaccines, pursuant to which Behringwerke will contribute its human vaccine
     business (hereinafter the "Business") to a newly organized limited
     partnership (hereinafter "VuCo GmbH & Co."). Buyer will purchase a 49%
     interest in the limited partnership and Buyer will have an option to
     purchase, and Behringwerke will have an option to require Buyer to
     purchase, the remaining 51% interest.

NOW, THEREFORE, the Parties hereto agree as follows:

1.   FACTS; COVENTANTS

1.1  Behringwerke is the sole shareholder of  32. CORSA Verwaltungsgesellschaft
     mbH (hereinafter "VuCo GmbH") and is holding two shares with a nominal
     value of DM 25,000 and DM 25,000  representing 100% of the stated capital
     of VuCo GmbH (hereinafter the "Shares"). VuCo GmbH is registered at the
     commercial register of Amtsgericht Frankfurt a.M. under HR B 40994.


1.2  Behringwerke is the sole limited partner (KOMMANDITISTIN) of VuCo GmbH &
     Co.; application has been filed for registration at the commercial register
     of Amtsgericht Marburg. Behringwerke's limited partnership interest will be
     fully contributed pursuant to the Contribution Agreement as defined in
     clause 1.4; an application has been filed to have registered as liability
     amount of Behringwerke at the commercial register an amount of  DM 70,000
     (in words: Deutsche Mark seventy thousand) (VOLL GELEISTETE
     KOMMANDITEINLAGE UND REGISTRIERTE HAFTEINLAGE).


<PAGE>

                                          7

1.3  Behringwerke is also the sole owner of Institut fur Produkttest und
     Verbrauchsforschung GmbH. ("IPV").

1.4  Presently "IPV" is the sole general partner of VuCo GmbH & Co. Behringwerke
     shall immediately after the date hereof cause VuCo GmbH to replace IPV as
     general  partner of VuCo GmbH & Co. and immediately after such replacement
     Behringwerke shall execute, and shall cause VuCo GmbH & Co. to execute, the
     Contribution Agreement attached as ANNEX 1.4 (a) ("the Contribution
     Agreement") and the limited partnership agreement attached as ANNEX 1.4 (b)
     (the "Partnership Agreement"), the latter with effect as of the Closing
     Date and also to be entered into by Buyer.

2.   SALE AND ASSIGNMENT

2.1  Behringwerke hereby sells to Buyer and Buyer hereby purchases from
     Behringwerke from its share in VuCo GmbH with a nominal value of DM 25,000
     (in words: Deutsche Mark twenty-five thousand) a partial share with a
     nominal value of DM 24,500 (in words: Deutsche Mark twenty four thousand
     five hundred) after split of such share in two shares with nominal values
     of DM 500 (in words: Deutsche Mark five hundred) and DM 24,500  (in words:
     Deutsche Mark twenty-four thousand five hundred). The transfer of the
     purchased share shall have effect as of the Closing Date, subject to the
     occurrence of all of the conditions at the Closing Date as defined in
     clause 5.1. (The sold share in VuCo GmbH is hereinafter referred to as the
     "GmbH Share".) From the Closing Date, Buyer shall be entitled to all
     dividend rights and all other secondary rights of the GmbH Share.

2.2  Behringwerke hereby sells to Buyer and Buyer hereby purchases from
     Behringwerke 49% of its limited partnership interests in VuCo GmbH & Co.
     including 49% of all capital accounts and of any other rights Behringwerke
     may have in VuCo GmbH & Co. (the "Limited Partnership Interest") with
     economical effect as of the Closing Date subject to the occurrence of all
     of the conditions at the Closing Date. Buyer shall be entitled to all
     dividend rights and all other secondary rights of a limited partner of VuCo
     GmbH & Co. with respect to the Limited Partnership Interest.


<PAGE>

                                          8

2.3  Behringwerke hereby assigns to Buyer with effect in rem as of the Closing
     Date the GmbH Share and the Limited Partnership Interest, and Buyer accepts
     such assignment from Behringwerke.

     The effectiveness in rem of the assignment of the GmbH Share and the
     Limited Partnership Interest shall in any case be subject to the condition
     precedent of payment of the Fixed Cash Purchase Price and of the Lease
     Compensation payable to Behringwerke pursuant to clauses 4.1 and 4.2 and
     the other conditions of clause 5.1.

2.4  Behringwerke shall cause VuCo GmbH to consent to the split of the DM 25,000
     share and to the transfer of the Limited Partnership Interest.


3.   PUT AND CALL; SHAREHOLDERS' AGREEMENT

3.1  Behringwerke herewith grants to Buyer the option (the "Chiron Call Option")
     to require Behringwerke to sell to Buyer all of the remaining shares of
     Behringwerke in VuCo GmbH and all of the remaining limited partnership
     interests in VuCo GmbH & Co. (the "Option Interests"). Buyer may exercise
     the Chiron Call Option within each of the following periods: March 1998,
     March 1999, March 2000, March 2001 (the "Call Option Periods").  For the
     purpose of executing the Chiron Call Option Behringwerke hereby irrevocably
     offers to the Buyer to sell the Option Interests within any of the Call
     Option Periods on the terms and conditions set forth herein. Buyer may
     exercise the Chiron Call Option by accepting the offer of Behringwerke by
     notarial deed within each of the Call Option Periods, PROVIDED THAT, Buyer
     gives a notice to Behringwerke 30 days before accepting the offer.

3.2  Buyer herewith grants to Behringwerke the option to require Buyer to buy
     from Behringwerke the Option Interests (the "Behring Put Option").
     Behringwerke may exercise the Behring Put Option within March 2001 (the
     "Put Option Period"). For the purpose of executing the Behring Put Option
     Buyer hereby irrevocably offers to Behringwerke to buy the Option Interests
     within the Put Option Period on the terms and conditions set forth herein.
     Behringwerke may exercise the Behring Put Option by accepting the offer of
     Buyer by notarial deed within the Put Option Period, PROVIDED THAT,
     Behringwerke gives a notice to Buyer 30 days before accepting the offer.


<PAGE>

                                          9


     In case a bankruptcy proceeding or composition proceeding is commenced with
     regard to the assets of VuCo GmbH or VuCo GmbH & Co., or the commencement
     of such proceedings is rejected due to lack of assets, Behringwerke is
     entitled to immediately exercise the Behring Put Option with a notice
     period of thirty days, PROVIDED THAT such notice shall not become effective
     if Buyer arranges that the continuation of VuCo GmbH and VuCo GmbH & Co. as
     a going concern is secured within such notice period.

3.3  Subject to the condition that either the Chiron Call Option or the Behring
     Put Option is exercised pursuant to clauses 3.1 or 3.2 above and subject to
     the further condition that the payment of the Option Purchase Price
     pursuant to clause 4.3 is made, Behringwerke hereby assigns to the Buyer
     the Option Interests and the Buyer accepts such assignment.  Behringwerke
     represents and warrants that as of the effective date of such assignment,
     it is the sole owner of such Option Interests and that the Option Interests
     are fully paid, not repaid and free and clear of any encumbrances and not
     subject to any restrictions on disposition, any preemptive rights, option
     rights, rights of first refusal or similar rights, all with respect to
     rights of third parties.

3.4  Buyer and Behringwerke herewith enter into the Shareholders' Agreement
     attached as ANNEX 3.4 which governs the Parties' shareholder rights in VuCo
     GmbH and VuCo GmbH & Co. for the time period until the exercise of the
     Chiron Call Option or the Behring Put Option.

4.   PURCHASE PRICE

4.1  The purchase price owed by Buyer for the GmbH Share and the Limited
     Partnership Interest is DM 171,500,000 (in words: Deutsche Mark one hundred
     and seventy-one million and five hundred thousand) (hereinafter the "Fixed
     Cash Purchase Price"). The payment of the Fixed Cash Purchase Price is due
     and payable on the Closing Date.

4.2  In addition to the Fixed Cash Purchase Price, Buyer shall pay to
     Behringwerke on the Closing Date 49% of the amount VuCo GmbH & Co. actually
     receives as rent under section 3.1 of the Operating Lease Agreement (the
     "Lease Compensation") entered into pursuant to the Contribution Agreement.

4.3  The purchase price owed by Buyer for the Option Interests is DM 178,500,000
     (in words: Deutsche Mark one hundred seventy-eight million and five hundred
     thousand)


<PAGE>

                                          10


     plus an amount equal to 51% of the Lease Compensation and plus an option
     fee calculated on such amounts at a rate of 5.125 % p.a. (in words: five
     and one eighth percent) compounded annually for the time period between the
     Closing Date and the due date under this clause 4.3 (the "Option Purchase
     Price"). Any dividends (ENTNAHMEN) received by Behringwerke from VuCo GmbH
     or VuCo GmbH & Co., plus interest, if and to the extent appropriate, on
     such amounts at a rate of 5.125 % p.a. (in words: five and one eighth
     percent) compounded annually for the time period between receipt of such
     dividend and receipt of payment under this clause 4.3 shall be credited to
     the Option Purchase Price, if due.

     The Option Purchase Price shall be due and payable within five days of the
     date of the notarization of the acceptance of the Chiron Call Option or the
     Behring Put Option, as the case may be.

4.4  Buyer shall make any payments owed under this clause 4 by wire transfer
     free of cost until 11:00 h at the respective due date to the following
     account of Behringwerke:

                                Commerzbank AG Marburg
                     A/C No. 391 0023 (BLZ/Bank ID-No 533 400 24)

     or any other account as designated by Behringwerke.

4.5  If the Closing Date is deferred for the sole reason that Buyer did not pay
     the full amount of the Fixed Cash Purchase Price and 49 % of the Lease
     Compensation or if Buyer does not pay the Option Purchase Price when due,
     then starting from such date at which the Closing Date otherwise would have
     occurred or the Option Purchase Price was due, the respective amount owed
     by Buyer shall bear interest until receipt of payment at a rate of 3-month
     FIBOR plus 10 basis points p.a.

4.6  The Fixed Cash Purchase Price and the Option Purchase Price include an
     amount of DM 35,000,000 (in words: Deutsche Mark thirty-five million) as
     consideration for the contribution of Stock in VuCo GmbH & Co. by
     Behringwerke pursuant to the Contribution Agreement or the Operating Lease
     Agreement and for investments in the Business which may be activated and
     which are implemented by Behringwerke since 1 January 1996 (the "New
     Investments"). The investments for 1996, as currently planned, approximate
     DM 6,700,000 (in words: Deutsche Mark six million seven hundred thousand)
     and are shown in the investment plan attached as ANNEX 4.6 which
     Behringwerke may alter at its discretion subject to this Agreement and
     the Contribution Agreement at any given time. Behringwerke will consult
     with Buyer from time to time regarding the implementation of


<PAGE>

                                          11



     such plan and any amendments thereto. The Parties shall make an inventory
     close to the Closing Date with respect to such Stock and the New
     Investments. The Parties shall evaluate the Stock and the New Investments
     considering generally accepted accounting principles in Germany and the
     principle of balance sheet consistency. If the value of the Stock and the
     New Investments as determined in accordance with the foregoing provisions,
     exceeds  DM 35,000,000, an amount of 49% of such excess amount shall be
     paid by Buyer to Behringwerke within 4 weeks after the Closing Date. If the
     value of the Stock and the New Investments as determined in accordance with
     the foregoing provisions is lower than DM 35,000,000, an amount of 49% of
     such shortfall shall be paid by Behringwerke to Buyer within 4 weeks after
     the Closing Date. As from the Closing Date any such payment owed by Buyer
     to Behringwerke, or by Behringwerke to Buyer, as the case may be, shall
     bear interest at a rate of 3-month FIBOR p.a. compounded annually. The
     remaining 51% of the balance shall be due and payable by Buyer to
     Behringwerke, or vice versa, as the case may be, at the date of the payment
     under clause 4.3, plus interest at a rate of 5.125% (in words: five and one
     eighth percent) compounded annually for the time period between Closing
     Date and receipt of such balance payment.

4.7  In addition to any purchase price payments hereunder, Buyer agrees to pay
     or to cause VuCo GmbH & Co. to pay to Behringwerke a yearly commission
     ("Commission") on the sales of Buyer's vaccine products listed in ANNEX 4.7
     in Germany calculated as [CONFIDENTIAL TREATMENT REQUESTED] of the excess
     of sales as forecast in ANNEX 4.7.  Any such Commission shall be payable 
     for each of the years through 2001, regardless of the date of exercise 
     of the Chiron Call Option or the Behringwerke Put Option, all further 
     regulated in ANNEX 4.7. To be clear: any such Commission received by 
     Behringwerke will not reduce the Fixed Cash Purchase Price and/or the 
     Option Purchase Price, if any.

4.8  Buyer cannot set off any claims including claims pursuant to clause 7 of
     this Agreement, it may have against any payments under this clause 4 unless
     the counterclaim is undisputed or non-appealable. The exercise of rights of
     retention of Buyer, if any, is also excluded. The same applies to payment
     obligations of Behringwerke pursuant to clause 4.6.

5.   CONDITION PRECEDENT

5.1  The date of perfection (VOLLZUG) of the transactions contemplated in this
     Agreement (the "Closing Date") is subject to the occurrence of each of the
     following conditions:


<PAGE>

                                          12


     5.1.1     VuCo GmbH & Co. is holding all official approvals for the
               operation of the Business as currently conducted pursuant to the
               ARZNEIMITTELGESETZ, GENTECHNIKGESETZ, TIERSCHUTZGESETZ and
               BUNDESSEUCHENGESETZ;

     5.1.2     the Operating Lease Agreement (cf. clause 6) has been terminated
               with effect as of the Closing Date;

     5.1.3     the Contribution Date pursuant to the Contribution Agreement has
               already occurred;

     5.1.4     the approval contemplated in Art. 7 of the Contribution Agreement
               shall have been obtained and the respective other contracting
               party referred to therein shall have consented to an assignment
               of the contract described in ANNEX 7 of the Contribution
               Agreement to VuCo GmbH & Co. (as VuCo GmbH & Co. will exist upon
               purchase of the GmbH Share and the Limited Partnership Interest
               by Buyer contemplated hereby); and

     5.1.5     the necessary merger control approvals pursuant to clause 13 have
               either been granted, regardless of whether subject to any
               conditions, or the implementation of this Agreement cannot be
               prohibited by the merger control authorities due to lapse of
               time.

5.2  The Parties shall use their best efforts that the events stated in clause
     5.1 will be fulfilled as soon as possible and they will promptly inform
     each other of the occurrence of any event stated in clause 5.1. All
     conditions shall be deemed to have occurred as soon as the Parties informed
     each other in writing of such occurrence.
     
5.3  Until Behringwerke shall have obtained the necessary approval referred
     to in clause 5.1.4, either party may initiate the following procedure by
     written notice, which may not be given earlier than 60 (sixty) days after
     the date hereof. If the condition precedent stated in clause 5.1.4 has not
     been fulfilled within such 60 (sixty) days period, each Party shall be
     entitled to terminate this Agreement, effective on five (5) days written
     notice to the other Party, without any Party being obliged to pay or
     entitled to receive any compensation by reason of such termination to or
     from the other Party. Neither Party is entitled to terminate this Agreement
     if  Behringwerke agrees at its own discretion within such period to effect
     a partial universal reorganization or other ways to reorganize in order to
     satisfy such condition and to indemnify Buyer against the cost and expense
     of any challenge regarding the effectiveness of such reorganization to
     cause the succession of VuCo


<PAGE>

                                          13


     GmbH & Co. to the contract described in Annex 7 of the Contribution
     Agreement without the consent of the respective other contracting party.

5.4  This Agreement shall be terminated if Closing Date has not occurred by
     October 31, 1996, unless mutually extended by the Parties.

5.5  On the Closing Date Behringwerke shall cause the managing director(s)
     (GESCHAFTSFUHRER) of VuCo GmbH to resign from office and Buyer and
     Behringwerke shall nominate a new managing director pursuant to the
     Shareholders' Agreement. Buyer shall also render a declaration that it
     waives all claims it or VuCo GmbH or VuCo GmbH & Co. may have against the
     resigning managing director.

5.6  On the Closing Date, Behringwerke shall deliver to Buyer a receipt for the
     purchase price received.

6.   OPERATING LEASE AGREEMENT

     The Operating Lease Agreement as provided for in the Contribution Agreement
     shall in any case become effective and shall run until the Closing Date.
     Behringwerke shall cause VuCo GmbH & Co. to agree to such effectiveness of
     the Operating Lease Agreement.

7.   BEHRINGWERKE'S REPRESENTATION AND WARRANTIES

7.1  Behringwerke represents and warrants in form of an independent guarantee
     (SELBSTANDIGES GARANTIEVERSPRECHEN) as of the date of this Agreement and
     the Closing Date, unless, otherwise stipulated and, excluding any further
     claims, that:

     7.1.1     it has all corporate-legal authorities to conclude and execute
               this Agreement and the execution and implementation of this
               Agreement have duly been authorized by all necessary corporate
               actions, in particular by its supervisory and managing bodies;

     7.1.2     assuming the necessary approvals referred to in clause 13 below
               will be granted and, except for circumstances exclusively within
               the sphere of Buyer, the execution, delivery and performance of
               this Agreement by Behringwerke do not and will not


<PAGE>

                                          14


     7.1.2.1   violate, conflict with or result in the breach of any provision
               of the Articles of Association or GESCHAFTSORDNUNG of
               Behringwerke,

     7.1.2.2   conflict with or violate any law, regulations, order, judgment,
               award, injunction, writ, decree or government order applicable to
               Behringwerke, nor

     7.1.2.3   require the consent of any third party including public
               authorities other than the approvals referred to in clauses 5.1.1
               and 5.1.4;

7.1.3     it is the sole owner of the fully paid in GmbH Share and of the
          Limited Partnership Interest (hereinafter collectively the "VuCo
          Interests") and is entitled to sell and transfer to Buyer the full
          legal and beneficial ownership of the VuCo Interests, and Buyer will
          own such interests

          free and clear from any encumbrances and will thereby become the sole
          owner of the VuCo Interests;

          VuCo GmbH has a net equity (BILANZIELLES REINVERMOGEN - Section 266
          III A HGB) in the amount of at least DM 50,000;

7.1.4     the VuCo Interests are not subject to any restrictions on disposition,
          any preemptive rights, option rights, rights of first refusal or
          similar rights of third parties;

7.1.5     the facts stated in clause 1 are true and correct;

7.1.6     no additional contribution obligations in cash or in kind
          (NACHSCHUBPFLICHTEN) exist with respect to VuCo GmbH and/or VuCo GmbH
          & Co.;

7.1.7     there are no voting trusts, stockholder agreements, proxies or other
          agreements or understandings in effect with respect to the voting or
          transfer of the VuCo Interests except as provided for in the articles
          of incorporation of VuCo GmbH and the Partnership Agreement;

7.1.8     the VuCo Interests do not constitute the entire property of
          Behringwerke within the meaning of sect. 419 of the Civil Code
          (BURGERLICHES GESETZBUCH);

7.1.9     The articles of incorporation (GESELLSCHAFTSVERTRAG) of VuCo GmbH are
          known to the Parties and will only be changed upon mutual consent;


<PAGE>

                                          15

7.1.10    ANNEX 1.4 (b) contains a true and correct copy of the Partnership
          Agreement to be effective on or before the Closing Date;

7.1.11    VuCo GmbH has not conducted any business activities other than
          administration as otherwise expressly contemplateed by this Agreement
          and is not subject to rights or obligations stemming from other
          business activities;

7.1.12    except for the JAHRESPRAMIENORDNUNG; ERFOLGSBETEILIGUNG, neither VuCo
          GmbH nor VuCo GmbH & Co. is bound by any control, profit transfer or
          other agreements of the type referred to in sect. 291, 292 ET SEQ. of
          the Stock Corporation Act (AKTIENGESETZ), and no silent participations
          (STILLE BETEILIGUNGEN), profit participating loans (PARTIARISCHE
          DARLEHEN), profit participations of management or employees or other
          similar obligations exist with respect to the profits of VuCo GmbH
          and/or of VuCo GmbH & Co. except for the Operating Lease Agreement
          (cf. clause 6);

7.1.13    sufficient insurance policies have been concluded and maintained to
          secure against risk arising in connection with the business of VuCo
          GmbH & Co. until the Closing Date; such insurance shall be continued
          for the period of joint ownership, while Hoechst is holding indirectly
          the majority in VuCo GmbH and VuCo GmbH & Co., unless VuCo GmbH & Co.
          and/or VuCo GmbH decides otherwise;

7.1.14    all warranties and representations granted by Behringwerke under the
          Contribution Agreement are true and correct, and Buyer is entitled to
          claim those warranties on behalf of VuCo GmbH & Co.;

7.1.15    between the date of this Agreement and the Closing Date, the
          Contribution Agreement will not be amended, the Business will be
          conducted in the ordinary course and consistent with past practice,
          and Behringwerke shall cause VuCo GmbH and VuCo GmbH & Co. not to
          enter into any transaction outside the ordinary course of business
          without the prior consent of Buyer. As amplification and not
          limitation of the foregoing, VuCo GmbH and/or VuCo GmbH & Co. will
          not:

7.1.15.1  make any loan to, guarantee any indebtedness of or otherwise incur any
          indebtedness on behalf of Behringwerke or any third party or assume
          any other unusual obligations;


<PAGE>

                                          16

7.1.15.2  redeem any of the capital or declare, make or pay any profit
          distributions (whether in cash, securities or other property);

7.1.15.3  enter into any arrangement under or similar to the Transformation Law
          (UMWANDLUNGSGESETZ);

7.1.15.4  purchase any assets or make any investments in excess of DM 50,000 (in
          words: Deutsche Mark fifty thousand), except as described in the
          capital investment plan, without the prior written consent of Buyer;

Behringwerke will not hire new employees attributable to the Business without
the prior consent of Buyer; in case of replacement of leaving employees, such
consent of Buyer shall not be unreasonably withheld;

7.1.16    neither the execution, delivery and performance of this Agreement by
          Behringwerke, the execution, delivery and performance of the
          Contribution Agreement by Behringwerke, VuCo GmbH and VuCo GmbH & Co.,
          nor the consummation of the transactions contemplated hereby and
          thereby, will (i) violate or conflict with Articles of Incorporation
          of Behringwerke or VuCo GmbH or the present partnership agreement of
          VuCo GmbH & Co., (ii) subject to clause 13 violate or conflict with
          any law, regulations, order, judgment, award, injunction, writ or
          decree applicable to Behringwerke, VuCo GmbH or VuCo GmbH & Co., (iii)
          subject to obtaining the third party consents with respect to the
          contracts listed in ANNEX 7.1.16 (the "Third Party Consents"), violate
          or conflict with, result in a breach of, or result in or permit the
          acceleration or termination of or constitute a default under (whether
          with notice or lapse of time or both) any agreement, instrument,
          indenture, mortgage, lien, lease or other contract to which
          Behringwerke, VuCo GmbH or VuCo GmbH & Co. is a party or by which any
          of them or their property or assets is bound, provided such violation,
          conflict, acceleration, termination of default individually or in the
          aggregate would have a material adverse effect on the Business; (iv)
          result in the creation of any lien, charge, or encumbrance on any of
          the property or assets of the Business which individually or in the
          aggregate would have a material adverse effect on the Business;

7.1.17    The Contribution Agreement completely and correctly identifies all
          contracts with licensors, contracts with licensees, leases, employment
          and labor agreements and other contracts relating to the Business
          (other than contracts with an

<PAGE>
                                          17

          annual payment obligation of no more than DM 50,000 and a term of less
          than one year). Except as disclosed in such Annexes, neither VuCo GmbH
          nor VuCo GmbH & Co. is a party or otherwise subject to (i) any
          contract, agreement or instrument evidencing or relating to any
          material amount of indebtedness for borrowed money or the deferred
          purchase price of property, or any direct or indirect guarantee of any
          such indebtedness or deferred purchase price, or (ii) any secrecy or
          other agreement or any injunction, judgment, order or award that (x)
          restricts the right of VuCo GmbH or VuCo GmbH & Co. to engage in any
          place in any line of business or (y) would restrict the right of VuCo
          GmbH or VuCo GmbH & Co. to engage in any place in any line of business
          after the Closing Date;

7.1.18    VuCo GmbH & Co. will receive good and marketable title to the
          intellectual property rights contributed pursuant to clause 3.1.1.1 of
          the Contribution Agreement and to the inventory and other stock
          contributed pursuant to clause 3.1.2 of the Contribution Agreement,
          and will also have good and marketable title to, or a valid leasehold
          interest in, the machinery, equipment and other fixed assets
          contributed pursuant to clause 3.1.1.2 of the Contribution Agreement,
          and except as expressly set forth in the Annexes to such clause or in
          ANNEX 7.1.18, all such assets are free and clear of any liens,
          pledges, usufruct, and other encumbrances;

7.1.19    to the best knowledge and belief of the management board (VORSTAND) of
          Behringwerke and officers (PROKURISTEN) of Behringwerke attributable
          to the Business, the financial statements contained in ANNEX 7.1.19
          fairly present the financial position and results of operation of the
          Business at the respective dates and for the respective periods to
          which they apply;

7.1.20    Behringwerke has disclosed all facts and circumstances which are or
          which can reasonably be expected to be material to Buyer;

7.1.21    Behringwerke, VuCo GmbH and VuCo GmbH & Co. each is in compliance in
          all material respects with all laws, regulations, orders, judgments
          and decrees of any court or governmental or administrative authority
          applicable to the Business so that there will be no material
          detrimental impact for the Business in future;

7.1.22    Since June 30, 1995, there has not been (a) any material adverse
          change in financial condition, operations, business prospects or
          properties of the Business; (b)

<PAGE>

                                          18

          any acquisition or disposition of any of assets of the Business which
          may have a material and adverse effect on the ability of VuCo GmbH &
          Co. to conduct the Business as heretofore conducted; (c) any damage,
          destruction or loss to any properties or assets of the Business which
          may materially and adversely affect or impair VuCo GmbH & Co.'s
          ability to conduct the Business in the manner heretofore conducted; or
          (d) any other act or event outside of the ordinary course of business
          which may materially and adversely affect or impair the ability of
          VuCo GmbH & Co. to conduct the Business in the manner heretofore
          conducted;

7.2  In case of a breach of any of the representations and warranties under
     clause 7.1 the following applies:

     7.2.1     Behringwerke is entitled, with respect to the warranted items, to
               cure the breach. If Behringwerke fails to cure the breach within
               a reasonable period of time, such period not to exceed three
               months after Buyer has notified Behringwerke of the breach, or if
               immediate action is necessary (GEFAHR IM VERZUG), Behringwerke
               shall refund to Buyer the necessary amount spent by Buyer to
               establish the warranted status and this shall be Buyer's sole
               remedy.

     7.2.2     Buyer may only ask for recovery based on a warranty claim or 
               on other claims connected therewith if the individual claim 
               exceeds [CONFIDENTIAL TREATMENT REQUESTED] (in words: 
               [CONFIDENTIAL TREATMENT REQUESTED]) and to the extent the 
               aggregate of all such individual claims exceeds [CONFIDENTIAL
               TREATMENT REQUESTED] (in words: [CONFIDENTIAL TREATMENT
               REQUESTED]). The total amount of the claims here mentioned may
               not exceed [CONFIDENTIAL TREATMENT REQUESTED] (in words: 
               [CONFIDENTIAL TREATMENT REQUESTED]) (the "Warranty Cap"), 
               whereby any warranty claims of VuCo GmbH & Co. pursuant to the 
               Contribution Agreement must be included in calculating the 
               Warranty Cap and the corresponding deductible amounts. This 
               clause 7.2.2 shall not apply with regard to clauses 7.1.1, 
               7.1.2 and with regard to the net equity guarantee pursuant to 
               clause 7.1.3 second paragraph.

7.3  To the extent that Buyer can raise a warranty claim for the same reason
     for which VuCo GmbH & Co. has raised and has got settled a warranty claim
     under the Contribution Agreement, Buyer is excluded to raise its warranty
     claim, notwithstanding that Buyer is entitled to claim those warranties on
     behalf of VuCo GmbH & Co.

7.4  Any claims regarding cancellation (WANDLUNG), rescission (RUCKTRITT) or
     challenge (ANFECHTUNG) of this Agreement or any other release from this
     Agreement, including any

<PAGE>

                                          19

     claim resulting from a liability due to breach of duty prior to contract
     (CULPA IN CONTRAHENDO), are excluded unless Buyer cannot reasonably be
     expected to adhere to this Agreement as a result of the breach of the
     guarantee pursuant to clause 7.1.22.  A breach of clause 7.1.22 by way of
     example and not limitation is considered as occurred if VuCo GmbH & Co's
     business or plant is subject to dislocation or massive destruction of
     production facilities which after insurance proceeds would result in a
     decline in value in excess of DM 52,500,000 (in words: Deutsche Mark 
     fifty-two million five hundred thousand).  Such extraordinary right of
     rescission has to be exercised within two weeks after the Closing Date.

     Any further claims for damages because of a breach of one or more of the 
     guarantees or representations and warranties made pursuant to clause 7 or
     any other liability of Behringwerke as well as claims based on breach of 
     duty prior to contract (CULPA IN CONTRAHENDO) shall be excluded.

7.5  Claims of Buyer pursuant to this clause 7 shall become time-barred fifteen
     (15) months after the Closing Date with the exception of the warranty
     granted under clause 7.1.14 which shall become time-barred as soon as the
     respective warranty claims of VuCo GmbH & Co under the Contribution
     Agreement become time-barred. The limitation period stops running if
     claims are asserted in writing by Buyer against Behringwerke and if the
     reasons on which such claim is based are reasonably identified. If
     Behringwerke does not accept the claim within one month, Buyer must raise
     the claim before court within a further period of three months pursuant to
     clause 15.5 or it becomes time-barred.

8.   USE OF NAME

     Buyer has the royalty free, worldwide exclusive right to use in
     perpetuity the name "Behring" as part of the firm of Buyer, VuCo GmbH
     and VuCo GmbH & Co. and to use such name and the logo "E. v. Behring"
     as described in ANNEX 8, provided, however, that the name and logo may
     only be used in connection with human vaccine products against
     infectious diseases and only in connection with a clear indication of
     the name of Chiron, all as also described in ANNEX 8. Such right to
     use the name Behring and the logo shall be subject to the
     non-exclusive right of Hoechst in India, Sri Lanka and Bangladesh and
     subject to any third parties' rights including not fully controlled
     affiliates.

<PAGE>

                                          20

     The parties will rename VuCo GmbH and VuCo GmbH & Co. within 6 (six)
     months after the Closing Date accordingly.

     Behringwerke is prepared to discuss with Buyer on a case by case basis the
     use of the name Behring in connection with the name Chiron outside of the
     vaccine field for human health care products based on modern biological
     technology (excluding Diagnostics) in as far as this is not in conflict
     with legal aspects and own interests of Behringwerke AG, Hoechst AG, and
     Centeon. All parties will guarantee that all uses will not damage the
     reputation of the name Behring. All discussions hereto will be conducted
     in good faith.

     All uses of the name by either Party will be of high quality and
     consistent with the preservation of the reputation and goodwill associated
     with the name.

     For the avoidance of doubt: Behringwerke shall remain the sole owner of
     the trade name and trademark "Behring" and of the logo "E. v. Behring",
     and all use of such trade name, trademark and logo in accordance with the
     aforesaid shall be governed by a "Trade Name and Trademark License
     Agreement" to be entered into by the relevant parties.

9.   BUYER'S REPRESENTATION AND WARRANTIES

9.1  Buyer represents and warrants in form of an independent guarantee
     (SELBSTANDIGE ERFULLUNGSGARANTIE) excluding any further warranty claims
     that:

     9.1.1     it has all corporate-legal authorities to conclude and execute
               this Agreement and the execution and implementation of this
               Agreement have duly been authorized by all necessary corporate
               actions, in particular by its supervisory and managing bodies;

     9.1.2     assuming the necessary approvals referred to in clause 13 below
               will be granted and except for circumstances exclusively within
               the sphere of Behringwerke, the execution, delivery and
               performance of this Agreement by Buyer do not and will not

               9.1.2.1   violate, conflict with or result in the breach of any
                         provision of the Articles of Association or
                         GESCHAFTSORDNUNG of Buyer,
<PAGE>

                                          21

               9.1.2.2   conflict with or violate any law regulations, order,
                         judgment, award, injunction, writ, decree or government
                         order applicable to Buyer, nor

               9.1.2.3   require the consent of any third party including public
                         authorities.

9.2  In the event that any of the representations and warranties made in clause
     9.1 is incorrect, Buyer shall indemnify Behringwerke for such damage
     Behringwerke may suffer as a result thereof.

10.  COOPERATION AFTER THE CLOSING DATE

10.1 Behringwerke and Buyer agree to cooperate after the Closing Date to achieve
     a smooth and efficient transfer of the VuCo Interests to Buyer.
     Behringwerke and Buyer shall initiate all acts necessary, or cause to be
     initiated such acts, respectively, to implement this Agreement.

10.2 Behringwerke and Buyer shall, without undue delay, pass to each other any
     payment, notice, correspondence, information or inquiry relating to the
     Business which may be received by either of them after the Closing Date
     and which the other is entitled to or is of concern to the other, taking
     into account the terms and conditions of this Agreement. Clause 12 is
     applicable to both Parties in this respect.

11.  NON-COMPETITION

     For a period of five years from the Closing Date, Behringwerke and
     affiliated companies except for VuCo GmbH or VuCo GmbH & Co. shall refrain
     from developing, producing, marketing, selling or otherwise distributing
     human vaccine products in the world; for such purposes an affiliated
     company of Behringwerke is a company in which Behringwerke either holds a
     majority interest or which is controlled by Behringwerke. In the letter
     attached hereto as ANNEX 11 Hoechst AG is undertaking a separate
     non-compete covenant and other covenants with respect to this Agreement
     (the "Hoechst Letter").

<PAGE>


                                          22

12.  CONFIDENTIALITY

     Except as otherwise provided in this Agreement, after the date of this
     Agreement Behringwerke shall not use or disclose to third Parties any
     information disclosed, transferred, assigned, licensed or otherwise made
     available by or to Buyer hereunder and relating to the transfer of the
     Business, unless (i) such information is needed by Behringwerke to
     continue its commercial activities, (ii) is or becomes public knowledge
     through no fault of Behringwerke, (iii) is passed to Behringwerke after
     the Closing Date by a third party which is not under an obligation of
     confidentiality, or (iv) has to be disclosed by Behringwerke pursuant to
     law, judicial, or official order; in such case Behringwerke shall notify
     Buyer in advance about the impending disclosure.

13.  MERGER CONTROL

13.1 Immediately after the date hereof, the Parties' respective counsel shall 
     determine whether this Agreement is subject to the merger control by the 
     Commission of the European Union (hereinafter "Commission") pursuant to
     the Regulation (EEC) No. 4064/89 of the Council of the European
     Communities of December 21, 1989 on the Control of Mergers between
     Undertakings. If so, they will notify the Commission on the merger
     contemplated in this Agreement promptly, but not later than one week after
     the date of notarization. Each party is obligated to provide all
     information and addresses necessary and useful in connection herewith in a
     timely, complete and correct manner and to take all steps necessary and
     useful to achieve a positive outcome of the merger control proceeding.

13.2 All legal acts relating to the consummation of this Agreement are subject
     to the condition precedent that either the Commission has found this
     Agreement to be compatible with the common market or that after the
     notification the prohibition of consummation shall be suspended for
     whatever reason.

     Both Parties shall only be released from the obligation resulting from
     this Agreement in the event that the Commission should deny its approval
     with respect to a transfer of the Business in total. In this context,
     Buyer shall conduct all negotiations with the Commission within due course
     and shall render to the Commission all additional details which shall
     enable the Commission to approve this Agreement, even if under conditions;
     furthermore, Buyer shall offer to the Commission or accept, respectively,
     to implement all acts the Commission deems necessary and shall then
     implement such acts accordingly.

<PAGE>

                                          23

13.3 In case that the Commission forbids the implementation of this Agreement
     in its entirety, the Parties shall regard such decision as final unless
     they agree otherwise until the decision becomes non-appealable.

13.4 In case the German Federal Cartel Office is in charge, clause 13.1 to 13.3
     shall apply respectively.

14.  INDEMNIFICATION; GUARANTEE

14.1 Buyer shall assume responsibility (SELBSTANDIGE ERFULLUNGSGARANTIE) by way
     of fulfillment of all obligations of VuCo GmbH & Co. stemming from the
     Contribution Agreement arising after the Closing Date.

     Buyer shall furthermore indemnify Behringwerke against any liability of
     Behringwerke as (former) limited partner after exercise of the Chiron Call
     Option or the Behring Put Option stemming from any repayment of the
     registered liability amount (HAFTEINLAGE) after the Closing Date.

14.2 The Guarantor shall assume responsibility (SELBSTANDIGEERFULLUNGSGARANTIE)
     by way of fulfillment of all obligations of Buyer stemming from this
     Agreement and its Annexes.

14.3 With respect to the Guarantor's obligation under clause 14.2 , it is
     agreed that the Guarantor shall enter into such reasonable and appropriate
     facilities as the Guarantor, Buyer and Behringwerke may from time to time
     agree.

15.  MISCELLANEOUS

15.1 This Agreement including the Annexes contains the entire understanding of
     the Parties hereto in respect of the subject matter contained herein. No
     agreements other than those expressly set forth herein exist between the
     Parties.

15.2 Any modifications or amendments of this Agreement including this clause
     15.2. shall be effective only if made in writing, unless the law provides
     for a stricter form.

15.3 Each party shall pay its own costs and expenses (including costs and
     expenses of its advisors) incurred in connection with this Agreement and
     the execution of the transac-

<PAGE>

                                          24

     tions contemplated hereby, except for the cost of notarization of this
     Agreement, which shall be borne by Buyer. The expenses for the
     cancellation of encumbrances not assumed by Buyer shall be borne by
     Behringwerke. Any taxes or court expenses and cost in connection with the
     merger control clearance which may arise from implementing this Agreement
     shall be borne by Buyer excluding any taxes based on income or capital
     gain which may arise upon the sale or transfer of the GmbH Share or the
     Limited Partnership Interest from Behringwerke to Buyer, which taxes shall
     remain the obligation of Behringwerke.

15.4 This Agreement shall be governed by and construed in accordance with the
     law of the Federal Republic of Germany (without rules of conflict of
     laws), unless the application of foreign law is compulsory.

15.5 Any disputes arising from, and in connection with, this Agreement shall be
     finally decided by an arbitration court consisting of three arbitrators
     following the rules of arbitration proceedings of the International
     Chamber of Commerce (ICC). The arbitration court shall meet in Frankfurt
     am Main. The language of the proceedings shall be German. The jurisdiction
     of the ordinary courts shall be excluded except for summary judgment
     (EINSTWEILIGER RECHTSSCHUTZ) and writs of execution. The arbitration court
     may also decide about the validity of this document if necessary. The
     costs of any arbitration shall be borne by the Parties pursuant to sect.
     91 et seq. of the Civil Procedure Code (ZIVILPROZEBORDNUNG).

15.6 To the extent possible, each provision of this Agreement will be
     interpreted in such manner as to be effective and valid under the
     applicable law. If any provision of this Agreement is held to be
     prohibited by or invalid under applicable law, such provision will be
     ineffective only to the extent of such prohibition or invalidity, without
     invalidating the remainder of such provision or the remaining provisions
     of this Agreement. To the extent that a provision is ineffective or
     invalid, it shall be replaced by an effective and valid provision which
     comes as close as possible to the economic purpose of the ineffective or
     invalid provision.

15.7 All notices and other communications under this Agreement shall be in
     writing and shall be given or made to the following addresses, unless
     specified otherwise in this contract:
<PAGE>

                                          25

     To Behringwerke:
          Behringwerke AG
          attn. Vorstand
          Postfach 1140
          D-35001 Marburg
          Fax:  (49-6421) 39-4880

     To Buyer/Guarantor:
          Chiron Corporation
          attn. President, Chiron Biocine
          4560 Horton Street
          Emeryville, CA 94608-2916
          U.S.A.
          Fax:  (1-510) 654-5360

          with a copy to General Counsel of Chiron Corporation, same address

15.8 It is agreed that Behringwerke shall cause the Behring/Armour joint
     venture to continue to have distributed in Germany by VuCo GmbH & Co. the
     products currently distributed by Behringwerke on behalf of such joint
     venture on existing terms for so long as VuCo GmbH & Co. is jointly owned.
     Further, it is agreed that the Parties shall cause VuCo
     GmbH & Co. to continue the existing arrangements between Behringwerke
     and Hoechst with respect to the distribution of human vaccine products
     outside Germany at arm's length terms to be agreed upon for not less
     than three years.

15.9 With respect to the Master Service Agreement as attached to the
     Contribution Agreement the following is agreed:

     As contemplated by sections 1.3 and 8.4 of the Master Service
     Agreement, the Services are to be defined in the Annexes and are to be
     divided into categories based upon the length of notice required to be
     given to terminate any such service. Neither the Annexes nor the
     division of the services into categories are complete as of the date
     hereof. The parties agree to complete the Annexes and the
     determination of which Services fall into which categories within six
     months of the Closing Date. Notwithstanding the foregoing the Parties
     agree that the Services will continue uninterrupted after the Closing
     Date. Buyer agrees that Category I will in particular include Services
     such as filling and packaging, production, logistics, materials 
     management, engineering, safety and environment.

15.10After signature of this Agreement, the Parties shall jointly issue a press
     release. Neither party shall, without the prior consultation of the other,
     issue any oral or written statement

<PAGE>

                                          26

     to the press or the public regarding this Agreement, except as required by
     law. This, in particular, applies with respect to the Purchase Price.

The present document with the annexes attached hereto was read aloud in the
presence of the appeared persons and signed by their own hands in my
presence as follows:

Basle, this 17th (seventeenth) day of February 1996 (nineteenhundred-
ninetysix).

<PAGE>


                                                                 ANNEX 1.4 (a)
                                                     to the Purchase Agreement

                                   AGREEMENT
                          ON CONTRIBUTION TO CAPITAL


between

Behringwerke Aktiengesellschaft
Emil-von-Behring-Strasse 76
35041 Marburg

- - HEREINAFTER "BEHRINGWERKE" -

a n d

Behring Vakzine GmbH & Co.
Emil-von-Behring-Strasse 76
35041 Marburg

represented by 32. CORSA Verwaltungsgesellschaft mbH in its capacity as general
partner of VuCo GmbH & Co., with same place of business

- - HEREINAFTER "VUCO GMBH & CO." -

(Behringwerke and VuCo GmbH & Co. are hereinafter collectively referred to as
the "Parties" or individually as the "Party", as the context requires.)


<PAGE>

                                          2


TABLE OF CONTENTS

Directory of Annexes . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Preamble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Article 1  -  Contribution . . . . . . . . . . . . . . . . . . . . . . . . 4

Article 2  -  Consideration. . . . . . . . . . . . . . . . . . . . . . . . 4

Article 3  -  Assets and Contracts to be Contributed . . . . . . . . . . . 5

Article 4  -  Transfer of Ownership; Implementation of the Contribution. . 8

Article 5  -  Takeover of Business; Periodical Delimitation. . . . . . . .10

Article 6  -  Warranties . . . . . . . . . . . . . . . . . . . . . . . . .15

Article 7  -  Contracts to be Contributed at a Later Date. . . . . . . . .18

Article 8  -  Use of Name. . . . . . . . . . . . . . . . . . . . . . . . .18

Article 9  -  Transition Period. . . . . . . . . . . . . . . . . . . . . .18

Article 10  -  Operating Lease Agreement . . . . . . . . . . . . . . . . .19

Article 11  -  Contracts to be Concluded . . . . . . . . . . . . . . . . .19

Article 12  -  Tax Law . . . . . . . . . . . . . . . . . . . . . . . . . .19

Article 13  -  Confidentiality . . . . . . . . . . . . . . . . . . . . . .19

Article 14  -  Miscellaneous . . . . . . . . . . . . . . . . . . . . . . .20


<PAGE>

                                          3


DIRECTORY OF ANNEXES

Annex  3.1.1.1 (a)      -    Contributed intellectual property
Annex  3.1.1.1 (b)      -    Licensed intellectual property
Annex  3.1.1.1 (c)      -    License Agreement (in favor of VuCo GmbH & Co.)
Annex  3.1.1.1 (d)      -    License Agreement (in favor of Behringwerke)
Annex  3.1.1.2          -    Fixed assets
Annex  3.1.3.1          -    Contracts with licensors
Annex  3.1.3.2          -    Contracts with licensees
Annex  3.1.3.3          -    Other contracts with third parties
Annex  5.1.1            -    Transferred employees
Annex  6.1.6            -    Shop agreements
Annex  6.1.7            -    Employment contracts with an annual remuneration
                             exceeding DM 300,000
Annex  7                -    Contracts to be contributed at a later time
Annex  10               -    Operating Lease Agreement
Annex  11.1             -    Master Service Agreement
Annex  11.2             -    Lease Agreement


<PAGE>

                                          4

PREAMBLE

Behringwerke and 32. CORSA Verwaltungsgesellschaft have formed VuCo GmbH & Co.
Pursuant to the Purchase and Assignment Agreement between Behringwerke and 31.
CORSA Verwaltungsgesellschaft mbH (to be renamed "Chiron Biocine GmbH") (the
"Purchase Agreement"), Behringwerke undertook the obligation to transfer its
human vaccine unit (the "Business") to VuCo GmbH & Co. as investment in kind.

NOW, THEREFORE, the Parties agree as follows:

ARTICLE 1 - CONTRIBUTION

1.1 As fulfillment of Behringwerke's obligation stemming from the Purchase
    Agreement described in the Preamble, Behringwerke contributes to the
    capital of VuCo GmbH & Co. the Business subject to the terms and conditions
    stated hereinafter and consisting of the assets and contracts described in
    Art. 3 with effect as of 1 April 1996, 00:00 h (the "Contribution Date").

1.2 VuCo GmbH & Co. accepts such contribution.

1.3 The value of the contribution of assets shall be determined pursuant to a
    balance sheet per the Contribution Date (the "Contribution Balance Sheet"),
    which shall include all assets and liabilities, if any, contributed hereby
    and assessed at their respective book values of Behringwerke. The
    Contribution Balance Sheet shall be prepared on a basis consistent with
    that adopted for previous fiscal time periods and in any case in accordance
    with the German generally accepted accounting principles ("GRUNDSATZE
    ORDNUNGSGEMASSER BUCHFUHRUNG UND BILANZIERUNG / GOB"). The Contribution
    Balance Sheet shall be testified by C&L Treuarbeit and the costs shall be
    borne by Behringwerke.

ARTICLE 2 - CONSIDERATION

2.1 Behringwerke shall receive as consideration a fixed capital interest in the
    capital account I kept by VuCo GmbH & Co. in the amount of DM 5,000,000 (in
    words:

<PAGE>

                                          5


    Deutsche Mark five million) as per the Contribution Date (the Kapitalkonto
    I - HAFTEINLAGE "Fixed Capital Interest").

2.2 To the extent that the Contribution Balance Sheet reflects a higher net
    equity value than the Fixed Capital Interest, VuCo GmbH & Co. shall credit
    the surplus in the capital account II of Behringwerke. The same shall apply
    for any subsequent contribution of Stock at the termination date of the
    Operating Lease Agreement (cf. Art. 3.1.2).

ARTICLE 3 - ASSETS AND CONTRACTS TO BE CONTRIBUTED

3.1 The assets and contracts to be contributed (hereinafter collectively
    referred to as the "Vaccine Assets") consist of the following:

    3.1.1 INTANGIBLE/TANGIBLE FIXED ASSETS

          3.1.1.1  All copyrights, patents, trademarks, drug licenses and other
                   intellectual property rights and registrations and
                   applications for registration with respect to any of the
                   foregoing, trade and operational secrets, know-how,
                   procedures, formulas and other intangible assets which are
                   not covered by the aforementioned intellectual property
                   rights, incorporation of such assets and ancillary
                   documents, such as application documents for drug licenses,
                   descriptions, product specifications, production
                   documentation and examination certificates, as well as all
                   sales literature, customers- and suppliers-lists,
                   transferable operational permits and approvals, all of the
                   aforesaid predominantly relating to the Business. The
                   registered intellectual property rights and trademarks are
                   listed in ANNEX 3.1.1.1 (a), which is to be updated as of
                   the Contribution Date and thereafter as provided for in
                   Article 3.2, 3.3 and 3.4;

                   Not part of the intangible assets contributed hereunder are
                   the  rights listed in ANNEX 3.1.1.1 (b) which is to be
                   updated as of the Contribution Date and thereafter as
                   provided for in Article 3.2, 3.3 and 3.4. Behringwerke
                   grants to VuCo GmbH & Co. upon the terms and conditions of
                   the License Agreement attached as ANNEX 3.1.1.1 (c) and
                   concluded herewith a royalty-free license to make use of
                   such rights. In return VuCo GmbH & Co. grants to
                   Behringwerke upon the terms and conditions of the License
                   Agreement attached as ANNEX 3.1.1.1 (d) and concluded
                   herewith a royalty-free license to make use of the rights
                   listed in ANNEX 3.1.1.1 (a) except for the trademarks.


<PAGE>

                                          6


          3.1.1.2  All machinery, equipment, office equipment and other fixed
                   assets including software shown in the books of Behringwerke
                   as being in a cost center related to the Business as listed
                   in ANNEX 3.1.1.2 which is to be updated as of the
                   Contribution Date and thereafter as provided for in Article
                   3.2, 3.3 and 3.4.

    3.1.2 STOCK

          All inventories, finished and semifinished products, raw materials,
          stocks, spare parts, information and promotional material and
          supplies allocated to the Business as well as advance payments for
          products previously sold but still held by Behringwerke, whereby
          Behringwerke shall have the right to exclude such products from
          inventory, all to be identified pursuant to a joint stocktaking close
          to the Contribution Date (hereinafter "Stock"). Stock which is
          produced under a license agreement is contributed and transferred
          subject to the condition subsequent that the respective licensor
          agrees to the transfer of the respective license agreement. In case
          that the respective licensor does not agree to the transfer of the
          respective license agreement, Behringwerke is free to sell such stock
          to any third party. If the Operating Lease Agreement provided for in
          Art. 10 becomes effective, no Stock shall be contributed by
          Behringwerke to VuCo GmbH & Co. pursuant to this Art. 3.1.2.

    3.1.3 CONTRACTS

          The following contracts of Behringwerke as well as offers relating to
          the Business:

          3.1.3.1  contracts with licensors attached as ANNEX 3.1.3.1;

          3.1.3.2  contracts with licensees attached as ANNEX 3.1.3.2;

          3.1.3.3  other contracts with third Parties including, without
                   limitation, with Hoechst and its affiliates other than
                   contracts otherwise dealt with in this Contribution
                   Agreement and/or the Purchase Agreement, attached as ANNEX
                   3.1.3.3, such annex, however, is limited to contracts
                   covering annual payment obligations of more than DM 50,000
                   or having a term of more than one year and not containing
                   purchase orders in the ordinary course of business;

          Behringwerke and VuCo GmbH & Co. shall use their best efforts to
          obtain the consent of the respective contract partners for the
          transfer to VuCo GmbH & Co. with-


<PAGE>

                                          7


          out undue delay after signature of this Agreement. Behringwerke
          herewith grants to VuCo GmbH & Co. a power of attorney to exercise
          all rights stemming from such contracts with respect to the time
          period between the Contribution Date and the date that such consent
          has been granted. As from the Contribution Date, VuCo GmbH & Co.
          shall hold Behringwerke free and harmless in respect of any
          obligations stemming from such contracts.

    3.1.4 All goodwill of and pertaining to the Business, including the right
          to use the name "Behring" in accordance with the further provisions
          of this Agreement.

3.2 As far as assets and contracts attributable to the Business are
    inadvertently not mentioned or not included in the respective Annexes, the
    Parties shall agree on a subsequent transfer or assumption in respect
    thereof and the Parties shall accept such transfer or assumption without
    consideration. Art. 7 remains unaffected.

3.3 As far as assets and contracts not attributable to the Business are
    inadvertently included in the respective Annexes, the Parties shall agree
    on a subsequent retransfer to or reassumption by Behringwerke thereof
    without consideration.

3.4 The exact identity of such Vaccine Assets which are to be identified by
    Annexes shall be governed exclusively by the Annexes updated as of the
    Contribution Date. With respect to ANNEX 3.1.1.1(b) it is agreed that any
    patent applications of Behringwerke filed with the relevant authorities
    within a period of one year after the Closing Date as defined in the
    Purchase Agreement shall be included in such annex and in the respective
    annex of the License Agreement attached as ANNEX 3.1.1.1(c), all subject to
    third parties' rights. With respect to ANNEX 3.1.1.1(a) it is agreed that
    any patent applications of VuCo GmbH & Co. filed with the relevant
    authorities within a period of one year after the Closing Date as defined
    in the Purchase Agreement shall be included in such annex and in the
    respective annex of the License Agreement attached as ANNEX 3.1.1.1(d).

3.5 The above provisions of Article 3.1.1.1 and 3.4 with respect to ANNEX
    3.1.1.1(b) shall apply MUTATIS MUTANDIS to any patents and patent
    applications of Hoechst AG arising out of an ongoing collaboration with
    Behringwerke or relating to existing products of the Business, PROVIDED
    THAT such right shall be granted on reasonable commercial terms, all
    subject to third parties' rights and to the consent of Hoechst AG.


<PAGE>

                                          8


ARTICLE 4 - TRANSFER OF OWNERSHIP; IMPLEMENTATION OF THE CONTRIBUTION

4.1 Behringwerke and VuCo GmbH & Co. are in agreement that the transfer of
    ownership of the Vaccine Assets from Behringwerke to VuCo GmbH & Co. shall
    be effected as of the Contribution Date. VuCo GmbH & Co. is entitled to
    take possession of the movable assets contributed to it under Art. 3.1.1.2
    and of the Stock, if contributed. As far as immediate possession is not
    possible, Behringwerke will possess the items with VuCo GmbH & Co.'s
    approval and according to its instructions (BESITZMITTLER).  As far as the
    movable assets contributed according to Art. 3.1.1.2 are in the possession
    of a third party on the Contribution Date, Behringwerke hereby assigns its
    respective rights and claims it may have against such third party with
    respect to such assets to VuCo GmbH & Co. with effect as of the
    Contribution Date.

4.2 If, due to the retention of title or other security interests of third
    Parties, Behringwerke has rights vested but not yet fully effective
    (ANWARTSCHAFTSRECHTE) with respect to the Vaccine Assets, Behringwerke
    hereby transfers these rights to VuCo GmbH & Co.

4.3 If and to the extent the transfer of ownership or assignment of other
    rights relating to the Vaccine Assets to be contributed requires additional
    acts which are not provided for in this Agreement, the Parties shall
    execute such acts promptly.

4.4 Behringwerke and VuCo GmbH & Co. shall take all action necessary for the
    implementation of this Agreement, including obtaining the necessary
    approvals of public authorities for the transfer of existing permits or
    applying for new permits and soliciting for necessary approvals of contract
    partners or other third parties.

4.5 If and to the extent an assignment of contractual rights and duties cannot
    be effected in relation to third parties, other than provided for in Art.
    7, Behringwerke shall be obliged to exercise the respective contractual
    rights and fulfill obligations in the interest of VuCo GmbH & Co. to the
    extent possible. The same shall apply to the extent necessary and possible
    with respect to the use of public permits. Behringwerke shall internally
    place VuCo GmbH & Co. in the same economic position as it would be in if
    such assignments had been valid and if that is not practicable it shall
    indemnify VuCo GmbH & Co. against all damages associated therewith. VuCo
    GmbH & Co. shall indemnify and internally place Behringwerke in the same
    economic position with respect to the performance by VuCo GmbH & Co.
    directly or indirectly of obligations of Behringwerke under such contracts,
    as though Behringwerke had been discharged from any further liabilities in
    respect


<PAGE>

                                          9


    thereof, but not for any breach caused by the transfer to or assumption by
    VuCo GmbH & Co. of such obligation.

4.6 As of the Contribution Date, all benefits and encumbrances (NUTZEN UND
    LASTEN) related to the Business as well as the risk of accidental loss and
    accidental deterioration of the Business shall pass to VuCo GmbH & Co.

4.7 If due, Behringwerke shall pay all public fees, charges and taxes relating
    to the Business attributable to the time before the Contribution Date,
    irrespective of whether such fees, charges and taxes have been levied at
    the Contribution Date including taxes attributable to the portion of any
    tax period which includes the Contribution Date from the beginning of the
    tax period through the Contribution Date.

4.8 Behringwerke shall pay any and all taxes based on income or capital gain
    imposed as a result of the contribution of assets to VuCo GmbH & Co.
    pursuant to this Agreement.

ARTICLE 5  -  TAKEOVER OF BUSINESS; PERIODICAL DELIMITATION

5.1 With respect to the assumption of employees, the following is agreed:

    5.1.1 As of the Contribution Date, VuCo GmbH & Co. shall assume all rights
          and obligations including pension entitlements, all pursuant to
          Section 613a of the German Civil Code (BGB), arising from the
          employment contracts of the employees of Behringwerke as listed in
          Annex 5.1.1.

    5.1.2 To the extent employees object to the transfer of their employment to
          VuCo GmbH & Co., such employees shall work in the Business until the
          earliest date at which such employments can be terminated, if
          possible, and VuCo GmbH & Co. shall compensate Behringwerke for all
          salaries and fringe payments and other costs related to continuing
          employment. All costs, if any, in connection with the termination of
          such employments shall be borne by Behringwerke. Behringwerke shall
          give priority to investigate whether there are comparable employment
          opportunities within Behringwerke, otherwise the employment of such
          employees shall be terminated with effect as of the earliest date
          possible.


<PAGE>

                                          10


          Behringwerke has the right to nominate employees replacing objecting
          employees with comparable qualification and salary and reasonably
          acceptable to VuCo GmbH & Co. VuCo GmbH & Co. may decline to accept
          such nominees, whether or not reasonably acceptable, but if a
          reasonably acceptable nominee is rejected, then VuCo GmbH & Co. shall
          bear all costs connected with the termination of the employment of
          the objecting employee to be replaced and shall hold Behringwerke
          free and harmless in this respect, unless Behringwerke decides at its
          sole discretion to employ such objecting employee elsewhere in its
          business. If the nominee is accepted, the provisions of this Article
          5 shall apply mutatis mutandis. Starting with the date at which VuCo
          GmbH & Co. employs any replacement employee, Behringwerke shall bear
          all costs connected with an employee who has been replaced because
          she/he objected to the transfer of her/his employment.

    5.1.3 To the extent that VuCo GmbH & Co. has assumed hereunder claims of
          employees pursuant to Section 613a of the German Civil Code (BGB) and
          such claims are attributable to the time prior to the Contribution
          Date, in particular claims for salary (including Christmas and
          vacation pay), vacation claims, bonus claims, settlements (including
          payments for employee inventions), life insurance premiums, and other
          payments to be made in addition to the regular salary, Behringwerke
          shall hold VuCo GmbH & Co. free and harmless therefrom.

    5.1.4 To the extent that VuCo GmbH & Co. has assumed hereunder pension
          obligations for employees pursuant to Section 613 a of the German
          Civil Code (BGB) attributable to the time prior to the Contribution
          Date, Behringwerke shall pay to VuCo GmbH & Co. an amount which
          approximates full cost of the pension liability. Full costs should be
          calculated in accordance with the provisions of FAS 87 using the
          biometric tables of Dr. Klaus Heubeck (amended as follows: mortality
          100%; disability 50%) and applying an interest rate of 7%, future
          salary rate increase of 4% and a fluctuation rate of 15% until age
          30, 10% until age 40, 5% until age 50, and 0% for 50+. The amount
          shall be calculated on the basis of an actuarial report
          (versicherungsmathematisches Gutachten) as of the Closing Date of the
          Purchase Agreement, to be prepared at Behringwerke's cost. Upon
          determination of the amount, such amount shall be payable within ten
          banking days to VuCo GmbH & Co. but in no case prior to the Closing
          Date of the Purchase Agreement.


<PAGE>

                                          11


    5.1.5 Behringwerke shall hold VuCo GmbH & Co. free and harmless against any
          taxes, social security contributions and contributions to workers'
          social associations (Berufsgenossenschaften) to be paid for the
          employees listed in Annex 5.1.1 or replacement employees transferred
          to VuCo GmbH & Co. pursuant to the second paragraph of clause 5.1.2
          attributable to the time period prior to the Contribution Date.

    5.1.6 If any employees other than those listed in Annex 5.1.1 are
          transferred to VuCo GmbH & Co. pursuant to Section 613a BGB,
          Behringwerke shall indemnify VuCo GmbH & Co. against all liabilities
          and expenses arising from such employments. VuCo GmbH & Co. shall
          terminate such employments as soon as legally possible. VuCo GmbH &
          Co. shall take all actions necessary or advisable to minimize any
          such liabilities or expenses of Behringwerke, including, without
          limitation, the use in any legal proceeding of all legal remedies
          available to it and the filing of appeals, all after due consultation
          with Behringwerke. VuCo GmbH & Co. may enter into settlements,
          provided, however, that it shall notify Behringwerke in writing in
          advance of such intention to settle and that Behringwerke does not
          object to such settlement within a period of three weeks after receipt
          of such written notification. The aforementioned provision shall not
          be applicable for the first seven employees who are attributable to
          the Business and have not been listed in Annex 5.1.1 as updated on the
          Contribution Date if and to the extent Behringwerke does not exercise
          its right to nominate replacement employees and VuCo GmbH & Co.
          employs such replacement employees or bears the severance costs.  For
          such seven employees this Art. 5.1 shall apply mutatis mutandis.

5.2  Notwithstanding anything to the contrary contained in this Agreement, VuCo
     GmbH & Co. shall not assume any costs, liabilities or expenses, whether or
     not related to the Business, other than (a) the pension obligations
     expressly assumed under clause 5.1.1, and (b) contractual obligations of
     the Business which accrue after the Contribution Date and which (i) are
     related to the contracts set forth in ANNEXES 3.1.3.1, 3.1.3.2, 3.1.3.3 AND
     7 or (ii) involve expenditures of less than DM 50,000 annually under
     contracts with a term of less than one year, or (iii) are related to
     purchase orders in the ordinary course of Business, or (iv) involve
     expenditures in connection with the License Agreements provided for in
     clause 3.1.1 (the "Assumed Liabilities"). With the exception of the Assumed
     Liabilities, VuCo GmbH & Co. shall not assume or otherwise be responsible
     for any liability or obligation of any nature of Behringwerke, whether or
     not related to the Business, or any claims of such liability or obligation,
     whether matured or unmatured, liquidated or unliquidated, fixed or
     contingent, known or unknown, whether arising out of occurrences prior to,
     at or


<PAGE>

                                          12


     after the Contribution Date. Subject to the foregoing, VuCo GmbH & Co.
     shall be responsible for any liabilities, obligations or damages incurred
     or caused after the Contribution Date in connection with the operation of
     the Business.

5.3  Notwithstanding anything to the contrary contained in this Agreement,
     Behringwerke shall hold VuCo GmbH & Co. free and harmless from all taxes,
     costs, liabilities and expenses related to the Business, in particular
     those arising from the contracts contributed and transferred under Art.
     3.1.3, attributable to the time prior to the Contribution Date. All costs,
     liabilities and expenses related to the Business and which are attributable
     to the time after the Contribution Date shall be borne by VuCo GmbH & Co.
     For the avoidance of doubt: Any capital expenses with respect to
     maintenance, repair and similar works incurred after the Contribution Date
     are attributable to the period after the Contribution Date unless the
     specific works causing the capital expense have been executed prior to the
     Contribution Date; ongoing works shall be split up accordingly.

5.4  All rents, rates, gas, water, electricity, and telecommunication costs,
     ancillary costs and other periodic expenditures relating to the Business
     incurred before the Contribution Date shall be borne by Behringwerke unless
     these are considered expenses related to a certain period after the
     Contribution Date and would therefore be shown as appertainment of payments
     pursuant to sec. 250 para. 1 Commercial Code (HGB) on the asset side. In
     the latter case they shall be borne by VuCo GmbH & Co. On or around the
     Contribution Date, the Parties will determine the uncharged consumption of
     gas, water, electricity, heating and other charges as basis for the
     apportionment of the expenses as stated above. To the extent that an exact
     apportionment is not possible, these expenses will be estimated.

5.5  All incoming payments received before the Contribution Date relating to the
     Business  shall belong to Behringwerke except for incoming payments
     attributable to the time after the Contribution Date which would be shown
     as appertainment of payments pursuant to sec. 250 para. 1 Commercial Code
     (HGB) on the liabilities side. All incoming payments received after the
     Contribution Date relating to VuCo GmbH & Co. shall belong to VuCo GmbH &
     Co. except for incoming payments if attributable to the time before the
     Contribution Date. Receivables attributable to any period starting before
     the Contribution Date and ending after the Contribution Date shall be split
     between Behringwerke and VuCo GmbH & Co. pro rata.

5.6  Behringwerke and VuCo GmbH & Co. shall initiate all action necessary for
     implementation of this Agreement and the takeover of the Business by VuCo
     GmbH & Co.


<PAGE>

                                          13


5.7  Behringwerke and VuCo GmbH & Co. agree to cooperate after the Contribution
     Date to achieve a smooth and efficient transfer of the Business to VuCo
     GmbH & Co.

5.8  Behringwerke and VuCo GmbH & Co. shall, without undue delay, pass to each
     other any payment, notice, correspondence, information or inquiry relating
     to the Business which is received by either of them after the Contribution
     Date and which the other is entitled to or which is of concern to the
     other, taking into account the terms and conditions of this Agreement; Art.
     13 is applicable to both Parties in this respect.

5.9  On or shortly after the Contribution Date or the termination of the
     Operating Lease Agreement, Behringwerke shall hand over to VuCo GmbH & Co.
     all documents, files, books etc., including the personnel files of the
     employees assumed by VuCo GmbH & Co. pursuant to Art. 5.1, except for such
     documents which Behringwerke must keep in its hands for legal reasons.
     Behringwerke hereby permits VuCo GmbH & Co. to review and to take copies of
     all retained documents to the extent necessary to continue the operation of
     the Business. Documents of the Business shall remain Behringwerke's
     property, as far as these are required to exercise rights and meet duties
     arising from the period prior to the Contribution Date, in particular if
     matters of taxation are involved.

5.10 Tax returns relating to the fiscal years prior to the Contribution Date
     are to be prepared by Behringwerke at its costs; with respect to the
     ongoing fiscal year of the Contribution Date, tax returns shall be jointly
     prepared by Behringwerke and VuCo GmbH & Co. and the costs shall be shared
     pro rata temporis. Behringwerke is entitled to designate the accountants
     for testifying the balance sheets and to file any legal remedies against
     levies and/or inspections of the tax authorities and social insurance
     institutions, relating to the time period until the Contribution Date.
     To the extent only VuCo GmbH & Co. can initiate the relevant action, it
     shall do so upon request and as directed by Behringwerke at Behringwerke's
     cost.

5.11 In case the Operating Lease Agreement provided for in Art. 10 becomes
     effective, this Art. 5 shall not be applicable as of the Contribution
     Date but as of such date the termination of the Operating Lease Agreement
     becomes effective, save that Art. 5.1.1 is applicable at both dates.

ARTICLE 6-  WARRANTIES

6.1 Behringwerke hereby warrants and represents in form of an independent
    guarantee (selbstandiges Garantieversprechen), excluding any further claims
    that on the date of signature of this Agreement and as of the Contribution
    Date


<PAGE>

                                          14


    6.1.1 the Vaccine Assets comprise all assets and contracts used in the
          operation of the Business as currently conducted, other than (a) the
          contract listed in Annex 7, which will be governed by the provisions
          of Article 7, (b) certain patent rights which are also used in the
          operation of  Behringwerke's other business units, for which VuCo
          GmbH & Co. will have a royalty-free license to use in accordance with
          the provisions of clause 3.1.1.1, (c) certain machinery, equipment,
          office equipment and other fixed assets which are also used in the
          operation of Behringwerke's other business units; such fixed assets
          will be operated on behalf of the Business by Behringwerke or its
          sub-contractors in accordance with the provisions of the Master
          Service Agreement, (d) certain real property, which will be leased to
          VuCo GmbH & Co. pursuant to the terms of the Lease Agreement, and (e)
          the contracts with Hoechst AG otherwise dealt with in this Agreement
          and/or the Purchase Agreement. Except as expressly set forth in the
          preceding sentence, upon contribution of the Vaccine Assets, VuCo
          GmbH & Co. will have all assets and contracts required for the
          continuation of the operation of the Business by VuCo GmbH & Co.,
          other than public permits that are person-related;

    6.1.2 it has full corporate power and authority to conclude and execute
          this Contribution Agreement, and that the execution and
          implementation of this Contribution  Agreement have been duly
          authorized by all necessary corporate actions, in particular by its
          supervisory and managing bodies;

    6.1.3 it is the sole owner of the respective intellectual property rights
          sold and transferred under Art. 3.1.1.1, except as set forth
          otherwise in the respective Annexes to Art. 3.1.1.1 or in Annex
          7.1.18 of the Purchase Agreement and said rights are free and clear
          of any liens, pledges, usufruct, and other encumbrances except as
          stated in the respective Annexes to Art. 3.1.1.1 and all measures
          necessary to maintain the protection of the intellectual property
          rights have been taken and, to the best knowledge, it does not
          infringe the rights of any other person;

    6.1.4 it is entitled to contribute all assets as provided for under Art.
          3.1.1.2 and that such assets are free and clear of all unusual liens,
          pledges, usufruct, option and use rights or any other encumbrances or
          rights of third parties, unless such encumbrances serve as security
          for obligations assumed by VuCo GmbH & Co. or unless otherwise stated
          in the respective Annexes;


<PAGE>

                                          15


    6.1.5 all public permits object-related, but not person-related, and
          necessary for the operation of the Business have been issued and
          there are no indications that such permits or licenses will be
          limited, recalled or revoked or become subject to new conditions
          (Auflagen), with the exception of those mentioned in the respective
          annexes;

    6.1.6 with respect to the Business no shop agreements
          (Betriebsvereinbarungen) have been concluded with the exception of
          those mentioned in Annex 6.1.6;

    6.1.7 except for those mentioned in Annex 6.1.7, it has not concluded any
          employment contracts attributable to the Business with an annual
          remuneration of more than [CONFIDENTIAL TREATMENT REQUESTED];

    6.1.8 there are no judicial or arbitration proceedings pending or to the
          best of its knowledge threatened with an amount in dispute of more
          than DM 300,000 in the aggregate and, to the best knowledge of the
          Vorstand of Behringwerke, it is not subject to any tax proceedings,
          all only to the extent that there are facts involved that could have
          a material detrimental impact on the Business;

    6.1.9 the Business between 30 June 1995 and the date hereof has been
          conducted in the customary manner, in particular, with respect to
          investments and maintenance of the assets and Stocks and no material
          assets outside the ordinary business have been acquired, sold,
          pledged or otherwise encumbered;

    6.1.10  all pension arrangements for the employees listed in ANNEX 5.1.1
            and transferred to VuCo GmbH & Co. pursuant to Section 613 a Civil
            Code (BGB) and the handling and documentation of respective rights
            including payments thereunder are in accordance with the present
            German legislation; except for those pension plans, no other
            commitments have been made nor additional pension claims exist.

6.2 In case of breach of warranty under Art. 6.1 the following applies:

    6.2.1   With respect to the warranted items Behringwerke is entitled to
            establish the warranted status. If Behringwerke fails to establish
            the warranted status within a reasonable period of time, such
            period not to exceed three months after VuCo GmbH & Co. has
            notified Behringwerke of the breach, or if immediate action is
            necessary (GEFAHR IM VERZUG), Behringwerke shall refund to VuCo
            GmbH & Co. the necessary amount spent by VuCo GmbH & Co. to
            establish the warranted status and this shall be VuCo GmbH & Co.'s
            sole remedy


<PAGE>

                                          16


    6.2.2   VuCo GmbH & Co. may only ask for recovery based on a warranty claim
            or on other claims connected therewith if the individual claim
            exceeds [CONFIDENTIAL TREATMENT REQUESTED] (in words: [CONFIDENTIAL
            TREATMENT REQUESTED]) and the aggregate of all such individual
            claims exceeds [CONFIDENTIAL TREATMENT REQUESTED] (in words:
            [CONFIDENTIAL TREATMENT REQUESTED]). The total amount of the claims
            here mentioned may not exceed [CONFIDENTIAL TREATMENT REQUESTED] (in
            words: [CONFIDENTIAL TREATMENT REQUESTED]) (the "Warranty Cap)",
            whereby any warranty claims of Buyer pursuant to the Purchase
            Agreement must be included in calculating the Warranty Cap and the
            corresponding deductible amounts.

6.3 Beyond the remedies mentioned in this Art. 6, VuCo GmbH & Co. shall have no
    further claims in connection with a breach of a warranty or corresponding
    claims. In particular, to the extent legally possible, all claims of VuCo
    GmbH & Co. going beyond the aforementioned remedies striving for additional
    capital contribution, cancellation (WANDELUNG) or any other form of
    rescission as well as a liability of Behringwerke based on breach of duty
    prior to contract (CULPA IN CONTRAHENDO) are excluded to the extent legally
    possible.

6.4 Claims of VuCo GmbH & Co. under this Art. 6  shall become time-barred
    fifteen (15) months after the Closing Date of the Purchase Agreement. The
    statute of limitation shall be interrupted if claims are asserted in
    writing by VuCo GmbH & Co. against Behringwerke and if the reason on which
    any such claim is based are reasonably identified. If Behringwerke does not
    accept the claim within one month, VuCo GmbH & Co. must raise the claim
    before court within a further period of three months; otherwise it becomes
    time-barred.

ARTICLE 7-  CONTRACTS TO BE CONTRIBUTED AT A LATER DATE

VuCo GmbH & Co. acknowledges that the assignment of rights and duties under the
contracts listed in ANNEX 7 requires the approval of the respective contracting
partner. Behringwerke shall seek to retain the approval for an assumption of
such contracts by VuCo GmbH & Co. If Behringwerke succeeds to obtain the
respective approvals, Behringwerke shall assign all rights and duties under such
contracts listed in ANNEX 7 to VuCo GmbH & Co. and the terms of this
Contribution Agreement shall be applicable to such contracts. If Behringwerke
cannot obtain the approvals, VuCo GmbH & Co shall not be entitled to any
compensation claims.

VuCo GmbH & Co. cannot assert any claims against Behringwerke based on this Art.
7.

ARTICLE 8-  USE OF NAME

Use of the name "Behring" and the logo "E. v. Behring" is governed by clause 8
of the Purchase Agreement.


<PAGE>

                                          17


ARTICLE 9-  TRANSITION PERIOD

Between the date of signature of this Agreement and the Contribution Date
(hereinafter "Transition Period"), Behringwerke shall continue to operate the
Business in the ordinary course, consistent with prior practice and maintain it
as an active operation and shall notify VuCo GmbH & Co. without undue delay upon
becoming aware of any circumstances which (would) lead to a breach of the
warranties set forth in Art. 6. During the Transition Period Behringwerke shall
not employ additional employees attributable to the Business other than such
necessary to replace leaving employees without the prior consent of VuCo GmbH &
Co.

ARTICLE 10-  OPERATING LEASE AGREEMENT

In the event that VuCo GmbH & Co. does not receive the necessary permits prior
to or on the Contribution Date and will thus not be able to continue the
operation of the Business, the Parties enter simultaneously herewith into the
Operating Lease Agreement attached as ANNEX 10.

ARTICLE 11-  CONTRACTS TO BE CONCLUDED

11.1      Behringwerke and VuCo GmbH & Co. enter simultaneously herewith into
          the Master Service Agreement attached as Annex 11.1.

11.2      Behringwerke and VuCo GmbH & Co. enter simultaneously herewith into
          the Lease Agreement attached as Annex 11.2.

ARTICLE 12-  TAX LAW

VuCo GmbH & Co. shall continue the valuation of assets as shown in the tax
balance sheet (STEUERBILANZ) of Behringwerke as of the Contribution Date.
Accordingly, no hidden reserves shall be disclosed and any goodwill shall not be
(newly) activated. The same applies for the commercial balance sheet
(HANDELSBILANZ) for which the book values of the VuCo Assets as determined in
the Contribution Balance Sheet are decisive.


<PAGE>

                                          18


ARTICLE 13-  CONFIDENTIALITY

Except as otherwise provided in this Agreement, after the date of this Agreement
Behringwerke shall not use or disclose to third Parties any information
disclosed, transferred, assigned, licensed or otherwise made available to VuCo
GmbH & Co. hereunder and relating to the transfer of the Business, unless (i)
such information is needed by Behringwerke to continue its commercial activities
or in connection with the Operating Lease Agreement, (ii) is or becomes public
knowledge through no fault of Behringwerke, (iii) is passed to Behringwerke
after the Contribution Date by a third party which is not under an obligation of
confidentiality, or (iv) has to be disclosed by Behringwerke pursuant to law,
judicial, or official compulsion; in such case Behringwerke shall notify VuCo
GmbH & Co. in advance about the impending disclosure.

ARTICLE 14-  MISCELLANEOUS

14.1      This Agreement including the Annexes contains the entire understanding
          of the Parties hereto in respect of the subject matter contained
          herein. No agreements exist other than those expressly set forth
          herein.

14.2      Any modifications or amendments of this Agreement or of any provision
          of this Agreement including this Art. 14.2 shall be effective only if
          made in writing, unless the law provides for a stricter form.

14.3      All expenses incurred in connection with this Agreement and the
          execution of the  transactions contemplated hereby shall be borne by
          Behringwerke.

14.4      This Agreement shall be governed by and construed in accordance with
          the law of the Federal Republic of Germany, unless the application of
          foreign law is compulsory.

14.5      To the extent possible, each provision of this Agreement will be
          interpreted in such manner as to be effective and valid under the
          applicable law. If any provision of this Agreement is held to be
          prohibited by or invalid under applicable law, such provision will be
          ineffective only to the extent of such prohibition or invalidity,
          without invalidating the remainder of such provision or the remaining
          provisions of this Agreement.  To the extent that a provision is
          ineffective or invalid, it shall be replaced by an effective and valid
          provision which comes as close as possible to the economic purpose of
          the ineffective or invalid provision.


<PAGE>

                                          19


Marburg, ______________ 1996



Behringwerke Aktiengesellschaft

by:



- ----------------------------             ------------------------------


VuCo GmbH & Co.

by:



- ----------------------------             ------------------------------

<PAGE>

                                                              Annex 3.1.1.1(a)
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (5 Pages)


<PAGE>

                                                              Annex 3.1.1.1(b)
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (5 Pages)


<PAGE>

                                                             ANNEX 3.1.1.1 (c)
                                                 to the Contribution Agreement



                                LICENSE AGREEMENT



between

Behringwerke Aktiengesellschaft
Postfach 1140
D-35001 Marburg

(hereinafter "Behringwerke")



and



Behring Vaccine GmbH & Co.

(hereinafter "VuCo GmbH & Co.")


<PAGE>


                                        2



Content
- -------


Preamble   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.        Granting of License. . . . . . . . . . . . . . . . . . . . . . . 3

2.        Royalty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3.        Term.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4.        Approval by Contract Partners. . . . . . . . . . . . . . . . . . 5

5.        Covenants by VuCo GmbH & Co. . . . . . . . . . . . . . . . . . . 5

6.        Maintenance of Protected Rights. . . . . . . . . . . . . . . . . 5

7.        Warranties by Behringwerke . . . . . . . . . . . . . . . . . . . 6

8.        Further Developments . . . . . . . . . . . . . . . . . . . . . . 7

9.        Assignment; Sub-Licensing. . . . . . . . . . . . . . . . . . . . 7

10.       Miscellaneous. . . . . . . . . . . . . . . . . . . . . . . . . . 7


<PAGE>

                                   3



PREAMBLE

Pursuant to the "Contribution Agreement" to which this License Agreement is an
annex, Behringwerke is contributing its human vaccine unit (the "Business") to
VuCo GmbH & Co. Some patents of, and actually used by, Behringwerke cannot be
transferred to VuCo GmbH & Co. as its property without restrictions because
these industrial property rights are also used by other units of Behringwerke.

In consideration hereof the parties agree as follows:

     1. GRANTING OF LICENSE

     1.1.   Behringwerke is the holder of the patents and applications for
            registration of patents listed in APPENDIX 1.1 (A) UNDER NO. 1, and
            respective know-how (hereinafter the "Patents").  The term Patent
            shall include continuations, divisionals, continuations-in-part,
            reissues, priority applications, and corresponding foreign
            counterparts.  Furthermore, Behringwerke is co-owner of the patents
            and applications for registration of patents listed in APPENDIX 1.1
            (A) UNDER NO. 2 (hereinafter the "Co-owned/Acquired Patents and Co-
            owned/Acquired Patents hereinafter collectively referred to as the
            "Protected Rights").

     1.2    Behringwerke hereby grants to VuCo GmbH & Co. subject to the terms
            and conditions set forth hereinafter a license or sublicense, as the
            case may be, under the Protected Rights to develop, manufacture, use
            and sell human vaccine products.  As to the Patents, such license
            shall be worldwide and exclusive.  As to the Co-owned/Acquired
            Patents, the territory and degree of exclusivity shall be as
            provided in the relevant agreement, if any, provided that if there
            is no such agreement the license will be worldwide and exclusive,
            all with respect to human vaccine products.


     2. ROYALTY

     The license under the Patents shall be royalty free.  Royalty obligations
     in respect of the development, manufacture, use or sale of human vaccine
     products under


<PAGE>

                                        4



     the Co-owned/Acquired Patents shall flow through directly to VuCo GmbH &
     Co. in the amount specified in the relevant agreement, if any, with no
     addition by Behringwerke.  Payments shall be made directly to the relevant
     licensor or co-owner.  Fixed sum royalties, if any, shall be shared between
     the parties in proportion to their respective use of such Protected Rights
     as measured by net sales of covered products.


3.   TERM

     3.1  This License Agreement becomes effective at the Contribution Date or,
          in case the Operating Lease Agreement becomes effective, upon
          termination of the Operating Lease Agreement.

     3.2  The licenses to the patents included in the Protected Rights shall
          expire on a country-by-country basis with the last to expire Protected
          Right.  The licenses to know-how included in the Protected Rights
          shall continue in perpetuity.  The licenses to Co-owned/Acquired
          Patents shall expire in accordance with the provisions of the relevant
          license agreement.

     3.3  VuCo GmbH & Co. may at any time terminate this License Agreement in
          its entirety or for single Protected Rights with a termination period
          of six months.

     3.4  Behringwerke may also terminate this License Agreement in its entirety
          or for single Protected Rights at any time with a termination period
          of six months, PROVIDED THAT Behringwerke offers to VuCo GmbH & Co. to
          transfer to VuCo GmbH & Co. without consideration all its rights and
          obligations with respect to such Protected Rights to be terminated.
          If VuCo GmbH & Co. accepts such an offer of transfer.  VuCo GmbH & Co.
          shall bear all costs incurred by the transfer. Furthermore,
          Behringwerke may terminate this License Agreement as to the Protected
          Right in question after respective warning and fruitless expiration of
          a period of 30 days after the warning without observing any notice
          period and without an offer to transfer any Protected Rights if VuCo
          GmbH & Co. is in breach of any material clause hereunder and such
          breach makes it unac-


<PAGE>

                                        5



          ceptable for Behringwerke to continue this License Agreement.
          Possible claims for damages by Behringwerke shall not be affected
          hereby.


     4.   APPROVAL BY CONTRACT PARTNERS

          To the extent the consummation of this License Agreement requires
          approvals of third parties under the terms of the agreements for the
          Co-owned/Acquired Patents, Behringwerke shall make every effort to
          receive such approvals without delay after the date hereof.  The
          provisions of Article 4.5 of the Contribution Agreement shall apply
          MUTATIS MUTANDIS to this License Agreement.


     5.   COVENANTS BY VUCO GMBH & CO.

          Within the limits of statutory liability VuCo GmbH & Co. shall
          indemnify and hold Behringwerke free and harmless against any claim
          (other than claims which would be covered by Article 6.1.3 of the
          Contribution Agreement, regardless of when such claims arise) which
          may be brought against Behringwerke by any third parties arising out
          of any use of the Protected Rights by VuCo GmbH & Co., except if such
          damages are caused by willful acts of Behringwerke or its personnel or
          any, licensee or its personnel.


     6.   MAINTENANCE OF PROTECTED RIGHTS

          6.1  For the term of this License Agreement Behringwerke is obligated
               to file, prosecute and maintain the Protected Rights, including
               all interferences and oppositions thereto, at its own cost.  In
               case Behringwerke intends to abandon a Protected Right it shall
               first make an offer of transfer to VuCo GmbH & Co. If the offer
               will not be accepted within 30 days, it shall be deemed to be
               rejected.  In case of acception VuCo GmbH & Co. shall bear all
               further costs.  In case of rejection Behringwerke may abandon the
               Protected Right.  Behringwerke shall make every reasonable effort
               to find a similar solution with respect to the Co-owned/Acquired
               Patents.


<PAGE>

                                        6



          6.2  In the event a third party infringes or may be infringing any of
               the Protected Rights in the field of human vaccines, the parties
               shall confer and consider whether any infringement proceedings
               should be filed against such third party.  Factors to be
               considered include, without limitation, the extent of such
               infringement, the identity of the infringer, the territory in
               question, the strength of the patent in that territory, the
               status of the patent in other territories, the likelihood of
               success, cost and resource allocation, and other possible methods
               of resolution.  The parties  will make every effort to mutually
               agree whether to file any action, including if necessary
               conferring with an independent third party, although in the event
               the parties are unable to agree, the final decision will be made
               by the owner of the patent at issue.  If the parties decide to
               proceed, VuCo GmbH & Co. shall control and bear the costs of such
               proceeding, and shall retain any recovery.  Behringwerke shall
               reasonably cooperate with and assist VuCo GmbH in connection
               therewith.

          6.3  To the extent the use of a Co-owned/Acquired Patent is linked to
               the exercise of an option, Behringwerke hereby authorizes VuCo
               GmbH & Co.to exercise such option in its own name or in the name
               of Behringwerke in order to enable VuCo GmbH & Co. to use the
               respective Protective Rights in accordance with this License
               Agreement. Furthermore, Behringwerke undertakes to make all
               necessary further declarations in order to enable VuCo GmbH & Co.
               to exercise the rights under the respective options. VuCo GmbH &
               Co. shall bear all costs incurred in connection with such
               exercise of options, including any royalty, as long as
               Behringwerke does not use the respective Protected Right. Art. 2
               of this License Agreement shall be applicable.


     7.   WARRANTIES BY BEHRINGWERKE

          Except as expressly set forth in the Contribution Agreement or the
          Purchase Agreement, any warranties and representations of Behringwerke
          are disclaimed.


<PAGE>

                                        7



     8.   FURTHER DEVELOPMENTS

          Except as expressly set forth in clause 3.4 of the Contribution
          Agreement, any new developments/improvements developed by Behringwerke
          or VuCo GmbH & Co. in connection with the Protected Rights remain the
          exclusive intellectual property of the respective party and are not
          subject to any disclosure obligation.  Each party is entitled to
          register such new developments/improvements and to make exclusive use
          of them for its own benefit.


     9.   ASSIGNMENT; SUB-LICENSING

          9.1  VuCo GmbH & Co. may assign or otherwise transfer the rights and
               obligations hereunder in whole or in part to a third party,
               PROVIDED THAT such third party is to be bound by the terms and
               conditions hereof and related hereto.

          9.2  VuCo GmbH & Co. is entitled to grant sub-licenses but restricted
               to the field of human vaccines.

          9.3  Behringwerke is free to assign any or all of its rights and
               obligations hereunder (i) in connection with a corporate
               restructuring, (ii) to Hoechst AG or companies affiliated with
               Hoechst AG or (iii) to an acquiror of the know-how and/or the
               Patents and Co-owned/Acquired Patents.

          9.4  Any assignment, sub-licensing and transfer of the Protected
               Rights is only admissible if the respective recipient undertakes
               to comply with the provisions of this License Agreement.


     10.  MISCELLANEOUS

          10.1 Unless otherwise defined herein, all terms used herein shall have
               the same meanings and definitions as in the Contribution
               Agreement.

          10.2 Unless otherwise specifically amended hereby all other terms of
               the  Contribution Agreement shall remain in full force and
               effect.


<PAGE>

                                        8



          10.3 To the extent possible, each provision of this License Agreement
               will be interpreted in such manner as to be effective and valid
               under the applicable law.  If any provision of this License
               Agreement is held to be prohibited by or invalid under applicable
               law, such provision will be ineffective only to the extent of
               such prohibition or invalidity, without invalidating the
               remainder of such provision or the remaining provisions of this
               License Agreement.  To the extent that a provision is ineffective
               or invalid, it shall be replaced by an effective and valid
               provision which comes as close as possible to the economic
               purpose of the ineffective or invalid provision.

          10.4 Any modifications or amendments of this License Agreement or of
               any provision of this License Agreement shall be effective only
               if made in writing, unless the law provides  for a stricter form.


          10.5 This License Agreement is governed by the laws of the Federal
               Republic of Germany.

          10.6 The exclusive place of jurisdiction shall be Marburg.



Marburg, the_______________



Behringwerke AG by:



____________________________________     ______________________________________


VuCo GmbH & Co. by:



____________________________________     ______________________________________


<PAGE>

                                                             APPENDIX 1. 1 (a)
                                    to License Agreement in favor of VuCo GmbH



                       [CONFIDENTIAL TREATMENT REQUESTED]

                                     (5 Pages)


<PAGE>

                                                              ANNEX 3.1.1.1 (d)
                                                  to the Contribution Agreement



LICENSE AGREEMENT



between

Behringwerke Aktiengesellschaft

Postfach 1140

D-35001 Marburg


(hereinafter "Behringwerke")



and



Behring Vaccine GmbH & Co.

(hereinafter "VuCo GmbH & Co.")


<PAGE>

                                        2



CONTENT


Preamble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
          
1.        Granting of License. . . . . . . . . . . . . . . . . . . . . . .3
          
2.        Royalty. . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
          
3.        Term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
          
4.        Approval by Contract Partners. . . . . . . . . . . . . . . . . .5
          
5.        Covenants by Behringwerke. . . . . . . . . . . . . . . . . . . .5
          
6.        Maintenance of Protected Rights; Exercise of Options . . . . . .5
          
7.        Warranties by VuCo GmbH & Co . . . . . . . . . . . . . . . . . .6
          
8.        Further Development. . . . . . . . . . . . . . . . . . . . . . .7
          
9.        Assignment; Sub-Licensing. . . . . . . . . . . . . . . . . . . .7
          
10.       Miscellaneous. . . . . . . . . . . . . . . . . . . . . . . . . .8


<PAGE>

                                        3



PREAMBLE

Pursuant to the "Contribution Agreement" to which this License Agreement is an
annex, Behringwerke is contributing its human vaccine unit (the "Business") to
VuCo GmbH & Co. Parts of the assets transferred to VuCo GmbH & Co. are also
patents which Behringwerke or affiliated companies intend to (further) use for
activities outside the Business.

In consideration hereof the parties agree as follows:

     1. GRANTING OF LICENSE

     1.1    Pursuant to the Contribution Agreement Vuco GmbH & Co. will become
            owner of the patents and applications for registration of patents
            listed in APPENDIX 1.1. (a) UNDER NO.1 (the "Patents") and
            respective know-how and a coowner of the patents and applications
            for registration of patents listed in APPENDIX 1.1.(a) UNDER NO. 2
            (hereinafter the "Co-owned/Acquired Patents").  The term Patent
            shall include continuations, divisionals, continuations-in-part,
            reissues, priority applications, and corresponding foreign
            counterparts.  Furthermore, Behringwerke transferred to Vuco GmbH &
            Co. rights and obligations relating to the license and option
            agreements listed in APPENDIX 1.1 (b) (hereinafter the "Licensed
            Patents"). (Patents, Co-owned/Acquired Patents and Licensed Patents
            hereinafter collectively referred to as "Protected Rights").

     1.2    VuCo GmbH & Co. hereby grants to Behringwerke subject to the terms
            and conditions set forth hereinafter a license or sublicense, as the
            case may be, under the Protected Rights to develop, manufacture,
            use, and sell any product other than human vaccine products.  As to
            the Patents, such license shall be worldwide and exclusive.  As to
            the Licensed Patents and the Co-owned/Acquired Patents, the
            territory and the degree of exclusivity shall be as provided in the
            relevant agreement, if any, provided tha that if there is no such
            agreement, the license will be worldwide and exclusive, all with
            respect to any products other than human vaccine products.

            VuCo GmbH & Co. shall have an option to obtain a non-exclusive
            sublicense back from Behringwerke to such Protected Rights on
            commercially


<PAGE>

                                        4



            reasonable terms for uses outside the field of human vaccines, but
            not for diagnostics.

     2. ROYALTY

        The license under the Patents shall be royalty free.  Royalty
        obligations in respect of the development, manufacture, use or sale of
        products under the Licensed Patents and the Coowned/Acquired Patents
        shall flow through directly to Behringwerke in the amount specified in
        the relevant agreement, with no addition by VuCo GmbH & Co.  Payments
        shall be made directly to the relevant licensor.  Fixed sum royalties,
        if any, shall be shared between the parties in proportion to their
        respective use of such protected rights as measured by net sales of
        covered products.

     3. TERM

        3.1    This License Agreement becomes effective at the Contribution Date
               or, in case the Operating Lease Agreement becomes effective, upon
               termination of the Operating Lease Agreement.

        3.2    The licenses to patents included in the Protected Rights shall
               expire on a country-by-country basis with the last to expire
               Protected Right.  The licenses to know-how included in the
               Protected Rights shall continue in perpetuity.  The licenses to
               Licensed Patents shall expire in accordance with the provisions
               of the relevant license agreement.

        3.3    Behringwerke may at any time terminate this License Agreement in
               its entirety or for single Protected Rights with a termination
               period of six months.

        3.4    VuCo GmbH & Co. may also terminate this License Agreement in its
               entirety or for single Protected Rights at any time with a
               termination period of six months, PROVIDED THAT VuCo GmbH & Co.
               offers to Behringwerke to transfer to Behringwerke without
               consideration all its rights and obligations with respect to such
               Protected Rights to be terminated.  If Behringwerke accept such
               an offer of transfer, Behringwerke shall


<PAGE>

                                        5



               bear all costs incurred by the transfer.  Furthermore, VuCo GmbH
               & Co. may terminate this License Agreement as to the Protected
               Right in question after respective warning and fruitless
               expiration of a period of 30 days after the warning without
               observing any notice period and without an offer to transfer the
               Protected Rights, if Behringwerke is in breach of any material
               clause hereunder and such breach makes it unacceptable for VuCo
               GmbH & Co. to continue this License Agreement.  Possible claims
               for damages by VuCo GmbH & Co. shall not be affected hereby.

     4. APPROVAL BY CONTRACT PARTNERS

        To the extent the consummation of this License Ageement requires
        approvals of third parties under the terms of the agreements for
        Protected Rights, the parties shall make any effort to receive such
        approvals without delay after the date hereof.  If any required
        approvals are not granted, the parties will make every effort to agree
        on an alternative solution with equal economic results; VuCo GmbH & Co.
        shall not be obligated to bear any costs thereby incurred.

     5. COVENANTS BY BEHRINGWERKE

        Within the limits of statutory liability Behringwerke shall indemnify
        and hold VuCo GmbH & Co. free and harmless against any claim which
        may be brought against VuCo GmbH & Co. by any third parties arising
        out of any use of the Protected Rights by Behringwerke, except if
        such damages are caused by willful acts of VuCo GmbH & Co. or its
        personnel or any licensee or its personnel.

     6. MAINTENANCE OF PROTECTED RIGHTS; EXERCISE OF OPTIONS

        6.1    For the term of this License Agreement VuCo GmbH & co. is
               obligated to file, prosecute and maintain the Patents and the Co-
               owned/Acquired Patents, including all interferences and
               oppositions thereto, at its own cost.  In case VuCo GmbH & Co.
               intends to abandon a Patent or a Co-owned/Acquired Patent it
               shall first make an offer of transfer to Behringwerke.  If the
               offer will not be accepted within 30 days, it is deemed to be
               rejected.  In case of acception Behringwerke shall bear all
               further costs.  In case of rejection VuCo GmbH & Co. may abandon
               the Protected Right.  VuCo GmbH & Co. shall make any reasonable
               effort to find a similar solution with respect to the Licensed
               Patents.


<PAGE>

                                        6



        6.2    To the extent the use of a Licensed Patent is linked to the
               exercise of an option, Vuco GmbH & Co. hereby authorizes
               Behringwerke to exercise such option in its own name or in the
               name of VuCo GmbH & Co. in order to enable Behringwerke to use
               the respective Protected Rights in accordance with this License
               Agreement.  Furthermore, VuCo GmbH & Co. undertakes to make all
               necessary further declarations in order to enable Behringwerke to
               exercise the rights under the respective options.  Behringwerke
               shall bear all costs, incurred in connection with such exercise
               of options, including any royalty as long as VuCo GmbH & Co. does
               not use the respective Protected Right. Art. 2 of this License
               Agreement shall be applicable.

        6.3    In the event a third party infringes or may be infringing any of
               the Protected Rights other than in the field of human vaccines,
               the parties shall confer and consider whether any infringement
               proceedings should be filed against such third party.  Factors to
               be considered include, without limitation, the extent of such
               infringement, the identity of the infringer, the territory in
               question, the strength of the patent in that territory, the
               status of the patent in other territories, the likelihood of
               success, cost and resource allocation, and other possible methods
               of resolution.  The parties will make every effort to mutually
               agree whether to file any action, including if necessary
               conferring with an independent third party, although in the event
               the parties are unable to agree, the final decision will be made
               by the owner of the patent at issue.  If the parties decide to
               proceed, Behringwerke shall control and bear the costs of such
               proceeding, and shall retain any recovery. VuCo GmbH & Co. shall
               reasonably cooperate with and assist Behringwerke in connection
               therewith.

     7. WARRANTIES BY VUCO GMBH & CO.

        Any warranties and representations of VuCo GmbH & Co. are disclaimed.


<PAGE>

                                        7



     8. FURTHER DEVELOPMENT

        Except as expressly provided in Art. 3.4 of the Contribution Agreement,
        any new developments/improvements developed by Behringwerke or VuCo GmbH
        & Co. in connection with the Protected Rights remain the exclusive
        intellectual property of the respective party and are not subject to any
        disclosure obligation.  Each party is entitled to register such new
        developments/improvements and to make exclusive use of them for its own
        benefit.

     9. ASSIGNMENT; SUB-LICENSING

        9.1    Behringwerke shall not assign or otherwise transfer the rights
               and obligations hereunder to a third party without the prior
               approval of VuCo GmbH & Co. In case Behringwerke sells its
               business operations or part thereof for which the Patents and
               Licensed Patents are needed, VuCo GmbH & Co. shall not withhold
               such approval, unless for good reason.  In any case, Behringwerke
               may transfer all its rights and obligations under this License
               Agreement to Hoechst AG or any company affiliated with Hoechst AG
               pursuant to Sec. 15 et seq. stock corporation act (AKTIENGESETZ)
               without the approval by VuCo GmbH & Co.

        9.2    Behringwerke is entitled to grant sub-licenses, with the
               exception of the production of human vaccines.

        9.3    VuCo GmbH & Co. is free to assign any or all of its rights and
               obligations hereunder (i) in connection with a corporate
               restructuring, (ii) to Chiron Corporation or companies affiliated
               with Chiron Corporation or (iii) to an acquiror of the know-how
               and/or Protected Rights.

        9.4    Any assignment, sub-licensing and transfer of the Protected
               Rights is only admissible if the respective recipient undertakes
               to comply with the provisions of this License Agreement.


<PAGE>

                                        8



    10. MISCELLANEOUS

        10.1   Unless otherwise defined herein, all terms used herein shall have
               the same meanings and definitions as in the Contribution
               Agreement.

        10.2   Unless otherwise specifically amended hereby, all other terms of
               the Contribution Agreement shall remain in full force and effect.

        10.3   To the extent possible, each provision of this License Agreement
               will be interpreted in such manner as to be effective and valid
               under the applicable law.  If any provision of this License
               Agreement is held to be prohibited by or invalid under applicable
               law, such provision will be ineffective only to the extent of
               such prohibition or invalidity, without invalidating the
               remainder of such provision or the remaining provisions of this
               License Agreement.  To the extent that a provision is ineffective
               or invalid, it shall be replaced by an effective and valid
               provision which comes as close as possible to the economic
               purpose of the ineffective or invalid provision.

        10.4   Any modifications or amendments of this License Agreement or of
               any provision of this License Agreement shall be effective only
               if made in writing, unless the law provides for a stricter form.

        10.5   This License Agreement is governed by the laws of the Federal
               Republic of Germany.

        10.6   The exclusive place of jurisdiction shall be Marburg.


<PAGE>

                                        9



Marburg, this _____th day of _______________________________ 1996


Behringwerke AG
by:



- ----------------------------------     --------------------------------------



VuCo GmbH & Co.
by:



- ----------------------------------     --------------------------------------


<PAGE>

                                                                Appendix 1.1(a)
                                  to License Agreement in favor of Behringwerke




                       [CONFIDENTIAL TREATMENT REQUESTED]

                                     (4 Pages)


<PAGE>

                                                                Appendix 1.1(b)
                                  to License Agreement in favor of Behringwerke



                       [CONFIDENTIAL TREATMENT REQUESTED]

                                     (1 Page)


<PAGE>

                                                                 Annex 3.1.1.2
                                                     to Contribution Agreement



This annex 3.1.1.2 is to be prepared by Behringwerke at the time of the
execution of the Contribution Agreement.


<PAGE>

                                                                 Annex 3.1.3.1
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (1 Page)


<PAGE>

                                                                 Annex 3.1.3.2
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (1 Page)

<PAGE>

                                                                 Annex 3.1.3.3
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (3 Pages)


<PAGE>

                                                                    Appendix 1
                                                              to Annex 3.1.3.3
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (3 Pages)


<PAGE>

                                                                   Annex 5.1.1
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (27 Pages)



<PAGE>


                                                                  ANNEX  6.1.6


                                BETRIEBSVEREINBARUNGEN
                                           
                                GRUNDSATZE/RICHTLINIEN
                                           
                                  UBERSICHT/SEITE I
                                           
Nr  Regelungsgageastand:

1.  Einheitliches Entgeltsystem mit Protokollnotizen und Einstufungs -,
    Einarbeitungs - und Durchlaufzeitenregelung

2.  Entgeltfortzahlung im Todesfall

3.  Jahrespramienordnung:  Erfolgsheteiligung

4.  Erschwerniszdlagen

5.  Vermogenswirksame Leistungen

6.  Zuwendungen bei Dienstjubilaen; Offizielle Feierstundo

7.  Gebuhrenerfassung u. abrechnung der Telefonanlage

8.  Werksbusfahrpreis:  SoBe Beschlub zum Werksbusfahrpreis

9.  Altersversorgung, Ende des Arbeitsverhaltnissen

10. Firmenrente; Witwenrente

11. Anderung der Beitragssatze in der Pensionskasse

12. Urlaubsgewahrung, Merkblatt zum aT Urlaubszuschull

13. Zushussee zur beruflichen Weiterbildung

14. Pensionierungsurlaub

15. Freizeitgewahrung fur Umzug

16. Altersfreizeit

17. Grundsatze zur Gewahrung bezahlter and unbezahlter Freistellung,
    Freistellung fur Prufungen

18. Arbeitsunfahigkeitbescheinigungen

<PAGE>

                                                                   ANNEX 6.1.6

                                BETRIEBSVEREINBARUNGEN
                                           
                                GRUNDSATZE/RICHTLINIEN
                                           
                                  UBERSICHT/SEITE 2
                                           

Nr  Regelungsgageastand:

19. Arbeitsordnung und Erganzungen zur Arbeitsordnung

20. Mitarbeitergesprach

21. Verarbeitung personenbezogener Mitarbeiterdaten

22. Durchfuhrung von Abteilungsfeicrn

23. Positive Zeiterfassung u. glcitende Arbeitszeit, Arbeitszcitverkurzungen

24. Grundsatze fur Bildschirmtatigkeit

25. Familie, Beruf, Teilzeit

26. Wahl von Ausbildungsgruppenspreeher

27. Mandatstragerregelung

28. Betriebliche Vertrauensleute

29. Betriebliches Vorschlagswesen

30. Alkohol im Betrieb Liste der Suchthelfer

31. Arbeitssicherhcit und Gesundheitsschutz

32. Ausweisregelung

33. Vorzeitige Pensionierung und Regelungsabrede

34. Neue Techniken

35. StraBenverkchrsordnung;  Parkordnung

36. Grundsatze der Mietgentaltung

<PAGE>

                                                                    ANNEX 6.1.6

                                BETRIEBSVEREINBARUNGEN
                                           
                                GRUNDSATZE/RICHTLINIEN
                                           
                                  UBERSICHT/SEITE 3
                                           

Nr  Regelungsgageastand:

37. Direktversicherung
    Verhutung-von Hepatiris-Infektionen;  Grundsatze zur HIV-Infektion

38. und zur Krannkheit AIDS;  Richtlinien zur Verhutung von Infektionen

39. Verwcndung von Kreditkarten bei Dienstreisen

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.


<PAGE>

                                                                   Annex 6.1.7
                                                     to Contribution Agreement



                                negative report


<PAGE>

                                                                       Annex 7
                                                     to Contribution Agreement



                          [CONFIDENTIAL TREATMENT REQUESTED]

                                      (1 Page)


<PAGE>

                                                                        ANNEX 10
                                                   to the Contribution Agreement



                              OPERATING LEASE AGREEMENT



between

Behringwerke Aktiengesellschaft
Postfach 1140
D-35001 Marburg

(hereinafter "Behringwerke")


and

Behring Vakzine GmbH & Co.

(hereinafter "VuCo GmbH & Co.).





                                       PREAMBLE

Pursuant to the (Contribution Agreement, of which this Operating Lease Agreement
is an annex, Behringwerke transfers its human vaccines unit (hereinafter the
"Business") to VuCo GmbH & Co. Since VuCo GmbH & Co. needs various permissions
to continue the Business, which it presently does not possess, the parties agree
that Behringwerke shall continue to operate the Business for a transfer period
on the basis of an operating lease agreement.

In consideration hereof, the parties hereto agree as follows:
 

<PAGE>

                                          2



1.  SUBJECT OF AGREEMENT

    Subject of this Operating Lease Agreement is the Business containing all of
    the Vaccine Assets operating property with the exception of the Stock which
    is owned by Behringwerke.


2.  BEGINNING AND DURATION OF THE AGREEMENT


    2.1  The lease shall come into force on the Contribution Date.


    2.2  The lease runs for an indefinite period.

    2.3  This Agreement is deemed to be terminated if all other
         conditions necessary for the occurrence of the Closing Date as defined
         in the Purchase Agreement are satisfied or waived.

    2.4  The right of the Parties to terminate the agreement without
         notice for good cause remains unaffected.


3.  RENT

    3.1  Behringwerke shall have the right to determine the
         amount of the rent as it deems appropriate.  It shall be paid at the
         end of each calendar month.

    3.2  Upon request of Behringwerke, VuCo GmbH & Co. shall submit an invoice
         separately showing the v.a.t.


4.  OPERATION OF BUSINESS

    4.1  As of the Contribution Date. Behringwerke shall operate the Business
         on its own account.

    4.2  Behringwerke is obliged to operate the Business in accordance with
         Art. 9 of the Contribution Agreement.  A sublet is not permitted.
         Behringwerke is not entitled to dispose any of the fixed assets of the
         Business.


<PAGE>

                                          3



    4.3  Behringwerke shall observe the regulations of the Industrial Act
         (Gewerbeordnung), the security regulations and all other regulations
         under public   law.

    4.4  By the end of this Agreement, Behringwerke shall transfer all new
         investments to VuCo GmbH & Co. pursuant to Article 7 para. 2 of this
         Agreement.

    4.5  Behringwerke shall be fully liable for all damages caused in
         connection with the Business and shall hold VuCo GmbH free and
         harmless from all claims in that respect.

    4.6  Behringwerke shall insure the assets in the previous extent.


5.  ASSIGNMENT OF EMPLOYMENT CONTRACTS

    Behringwerke assumes pursuant to sect. 613 a BGB (Civil Code) for the
    duration of this Agreement the entire workforce of the Business and the
    rights and obligations as of the Contribution Date stemming from the
    employment contracts and pension liabilities relating to employees still
    active.

6.  WARRANTY

    Any warranties and representations by VuCo GmbH & Co. are excluded.


7.  TERMINATION OF THE OPERATING LEASE AGREEMENT

    7.1  Upon the termination of this Agreement, the transfer of the Business
         is governed by Articles 4 and 5 of the Contribution Agreement and by
         the regulations set forth hereinafter.

    7.2  At the date of the end of this Agreement, Behringwerke shall transfer
         to VuCo GmbH & Co. the Stock which belongs to the Business and the new
         investments according Article 4 para. 4 of this Agreement.  For this
         purpose, VuCo GmbH & Co. and Behringwerke shall conduct a stock-taking
         of the Stock and of the new investments (hereinafter "Stock-Taking")
         close to the


<PAGE>

                                           4



         day of the termination of this Agreement.  The book value of the
         aforementioned objects shall be credited to capital accounts I and II
         as provided in Art. 2 of the Contribution Agreement.

    7.3  To the extent meaningful, the regulations of the Contribution
         Agreement shall be applicable, mutatis mutandis, with respect to the
         retransfer of the Business to VuCo GmbH & Co.


8.  MISCELLANEOUS

    8.1  Unless otherwise defined herein, all terms shall have the same
         meanings and definitions as in the Contribution Agreement.

    8.2  Unless otherwise specifically amended hereby, all other terms of the
         Contribution Agreement shall remain in full force and effect.

    8.3  To the extent possible, each provision of this Agreement will be
         interpreted in such manner as to be effective and valid under the
         applicable law.  If any provision of this Agreement is held to be
         prohibited by or invalid under applicable law, such provision will be
         ineffective only to the extent of such prohibition or invalidity,
         without invalidating the remainder of such provision or the remaining
         provisions of this Agreement.  To the extent that a provision is
         ineffective or invalid, it shall be replaced by an effective and valid
         provision which comes as close as possible to the economic purpose of
         the ineffective or invalid provision.

    8.4  Any modifications or amendments of this Agreement or of any provision
         of this Agreement including this Art. 8.4 shall be effective only if
         made in writing, unless the law provides for a stricter form.

    8.5  This Agreement is governed by the laws of the Federal Republic of
         Germany.

    8.6  The exclusive place of jurisdiction shall be Marburg.


<PAGE>

                                                                      Annex 11.1
                                                   to the Contribution Agreement



                               MASTER SERVICE AGREEMENT



between


Behringwerke AG

35001 Marburg

- - hereinafter "Behringwerke" -


and


Behring Vakzine GmbH & Co.



hereinafter "VuCo GmbH & Co." -


<PAGE>

                                           2



                                       PREAMBLE

A.  Pursuant to the Contribution Agreement to which this Agreement is an Annex
    and to the Purchase and Assignment Agreement entered into by Behringwerke
    and 31. CORSA Verwaltungsgesellschaft mbH (the "Purchase Agreement"),
    Behringwerke is contributing its human vaccine unit (the "Business") to
    VuCo GmbH & Co. VuCo GmbH & Co. will, for the foreseeable future,
    continue to conduct the  Business within the premises of Behringwerke on a
    lease basis.  Therefore, and due to the numerous operational and
    technological interdependencies between the business operations of
    Behringwerke and VuCo GmbH & Co., the Parties agree that both will
    require supply of certain goods and services from the respective other
    Party.

B.  In this Agreement, the Parties wish to stipulate the terms and conditions
    applicable to such supply of goods and services.

C.  In order to facilitate the efficient supply of goods and services by
    Behringwerke to VuCo GmbH & Co. and vice versa and to ensure that each
    Party may plan ahead to remain cost-effective and within the terms and
    conditions set forth herein, it is important that the Parties advise each
    other on a cooperative basis of their requirements and timetables.


Article I - Services Supplied under this Agreement

1.1 Subject to the terms and conditions set forth herein, Behringwerke will
    supply VuCo GmbH & Co. with goods and services listed in ANNEXES (the
    "Behringwerke Services"), VuCo GmbH & Co. will receive and accept such
    Behringwerke Services from Behringwerke.

    Behringwerke may use Hoechst or Centeon Pharma GmbH or affiliates residing
    on Behringwerke's premises or other third parties, the latter only to the
    extent the services do not require the trust of VuCo GmbH & Co. such as
    painting (hereinafter collectively "Internal Partners") as a sub-contractor
    in order to meet its obligations under this Agreement with respect to such
    Behringwerke Service. and nothing in this Agreement shall limit such right
    of sub-contracting.


<PAGE>

                                           3



1.2 Subject to the terms and conditions set forth herein, VuCo GmbH & Co. will
    supply Behringwerke with goods and services listed in ANNEXES - (the `VuCo
    Services"; Behringwerke Services and VuCo Services are hereinafter
    collectively referred to as the "Services").  Behringwerke will receive and
    accept such Services from VuCo GmbH &  Co. It is further understood that
    Behringwerke may pass on and transfer any VuCo GmbH & Co. Services to
    Internal Partners.

1.3 The Services are individually defined as to their nature in Annexes.  All
    Services will be provided in the same amount as provided in 1995, adjusted
    to reflect Behringwerke's projections for 1996: provided, that either Party
    may request an additional amount of any Service, and the provider of such
    Service shall use reasonable commercial efforts to provide such additional
    amount.

1.4 Due to the Business being located within the Behringwerke premises and the
    said technological interdependence, it is mandatory that Behringwerke
    supplies and VuCo GmbH & Co. receives the Behringwerke Services listed in
    ANNEXES - (such as utilities and fire brigades).  VuCo GmbH & Co. will
    receive such Behringwerke Services exclusively from Behringwerke.  For the
    same reasons, it is mandatory that VuCo GmbH & Co. supplies and
    Behringwerke receives the VuCo GmbH & Co. Services listed in ANNEXES - .

    These Services cannot be terminated during the term of the Lease Agreement.

1.5 Services other than those defined in the Annexes hereto are not part of
    this Agreement and may be agreed upon separately in each single case
    pursuant to Art. 1.8. In particular, the Parties will enter into a separate
    lease agreement regarding the use by VuCo GmbH & Co. of parts of
    Behringwerke's premises.

1.6 Whenever one of the Parties and/or any of the Internal Partners needs goods
    and services in addition to those listed in ANNEXES -  and the other Party
    could also be considered as a supplier of such additional goods and
    services, the other Party shall be requested to tender them.  If such goods
    and services are nevertheless obtained from an outside supplier, the other
    Party is to be advised of the reasons for such decision.  At equal cost-
    effectiveness and comparable other terms and conditions, the respective
    other Party shall be preferred to any outside supplier.


<PAGE>

                                           4



1.7 If VuCo GmbH & Co. in addition requires special goods and services which
    are not available or are not available in the desired quality or quantity
    or at the desired time(s), Behringwerke will make every reasonable effort
    to supply these additional goods and services, too, without, however, being
    obliged to do so.  Any additional costs resulting from the supply of these
    additional goods and services will be borne by VuCo GmbH & Co. at a price
    to be negotiated between the Parties.  If the additional goods and services
    are also used by other internal customers of Behringwerke, the additional
    costs will be shared proportionately, based on use, between Behringwerke
    and VuCo GmbH & Co.

1.8 If and when such additional goods and services referred to in Art. 1.6 or
    1.7, above, are purchased from the respective other Party, the respective
    Services shall be listed in new Annexes in the form of ANNEXES -  setting
    forth all information necessary and signed on behalf of each Party by a
    duly authorized signatory (the supply of such goods and services shall be
    considered "Behringwerke Services" or "Vu-Co Services", as the case may be,
    and "Services" in each case) and the provisions of this Agreement shall be
    applicable to such goods and services.


Article 2 - Principles Governing the Supply of Services

2.1 The Parties shall supply the Services in the same kind and quality as if it
    were for captive use (SORGFALT IN EIGENEN ANGELEGENHEITEN).  They will
    allocate qualified staff to the supply of the Services.  Employees
    transferred to VuCo GmbH & Co pursuant to the Contribution Agreement shall
    be deemed qualified for the position held as of the Closing Date.

2.2 Each Party shall observe that the Services supplied by it are supplied, and
    that its operations for which the other Party supplies such Services are
    conducted, in accordance with the applicable legislation.

    The Parties shall observe in particular the technical regulations in
    respect of pharmaceutical products for human use and the products comprised
    in the business of the respective other Party, as well as applicable law,
    ordinances or orders of public authorities.  In addition, the Parties shall
    comply with any health and safety regulations or requirements protecting
    employees and third parties in the sites and buildings or parts thereof
    occupied by the Parties.


<PAGE>

                                           5



2.3 When supplying Services under this Agreement, each Party shall comply with
    the respective other Party's requests as to the specific circumstances of
    such supply to the extent reasonable and possible.  Neither Party is,
    however, obliged to comply with such requests if there are reasons to
    assume that compliance would breach any legislation in force, lead to
    damages to its installations or its property or property of third parties
    or could be associated with exposure to danger of persons.  In such case,
    the respective Party shall promptly inform the other Party of the reasons
    of its concern and discuss appropriate actions with the other Party to
    avoid disadvantages to such other Party as far as reasonably possible.

2.4 If either Party needs official authorization for its supply of Services
    hereunder such Party will prepare the appropriate applications together
    with, and in consultation with, the Party receiving the Services and submit
    them to the authorities.  Behringwerke and VuCo GmbH & Co. will keep each
    other regularly informed on the progress made in such matter and on their
    respective negotiations with the authorities and will discuss in advance
    any necessary measures.

    Behringwerke and VuCo GmbH & Co. shall, in particular, promptly inform each
    other if official action is likely to be initiated which could result in
    the withdrawal or revocation of any authorization for those operations of
    VuCo GmbH & Co. and of Behringwerke which relate to the Services under this
    Agreement.

2.5 Behringwerke and VuCo GmbH & Co. will regularly discuss questions of common
    interest regarding the supply of Services hereunder and regarding those
    units supplying such Services.  Should one of the Parties intend to modify
    its operations in a way which would have significant effects on its future
    need for Services supplied by the other Party, it will inform the other
    Party without delay in order to allow for a joint examination and
    discussion of the effects of such modification on the mutual service
    relationships and to enable the respective other Party to provide an
    initial assessment of the resulting cost increases or reductions to serve
    as a basis for such discussions. In such case, the Parties will make every
    reasonable effort to supply each other with additional amounts of Services
    in the most economical way.


<PAGE>
                                           6



Article 3 - Quantity and Measurement of Services

3.1 Unless otherwise provided for in ANNEXES - , the amount of any Services
    continuously supplied in accordance with such Annexes shall be reviewed by
    the Parties on or before September 30 of each year for the following year.

    To the extent the Parties are unable to reach an agreement on the amount of
    any
    Services to be supplied during the following year, the following applies:

    3.1.1     in case of increased demand, the supplying Party will endeavor to
              meet such demand, but will only be obliged to supply such
              Services in the amount agreed upon for the current year;

    3.1.2     in case of reduced demand, the supplying Party will supply only
              the requested amount of such Services; however, if the supplying
              Party proves that it incurred any residual costs due to such
              reduction, it shall be indemnified by the receiving Party, unless
              otherwise provided for herein.

3.2 Subject to Art. 1.3, the methods, places and other particulars of
    measurement of any measurable Services (e.g., in time, quantities of
    energy, etc.), and the allocation method with regard to any non-measurable
    Services (e.g., security, fire brigade) or for which metering devices are
    not available, are provided for in the respective Annexes.  The Parties
    shall review such provisions as part of the annual review pursuant to Art.
    3.1.


Article 4 - Remuneration

4.1 Services shall be provided at Cost as defined in Art. 4.2.

4.2 "Cost" means the fully burdened, fairly allocated cost of providing the
    relevant Services, which shall include a reasonable return on employed
    capital and reasonable depreciation and amortization of employed assets
    over their useful lives, and a fairly allocated charge for underutilized
    plant and equipment, provided that each Party uses its best efforts to
    employ such plant and equipment otherwise.  Cost shall be determined
    pursuant to reasonable and customary allocation and calculation
    methodologies as consistently applied by Hoechst AG and Guarantor and which
    are consistent with German GAAP; provided that neither Parties' method-


<PAGE>
                                           7



    ologies will be applied in a manner that would cause the Costs charged to
    the other Party to exceed the costs as would be calculated in accordance
    with the methodologies reflected in the financial statements as attached in
    Annex 7.1.19 of the Purchase Agreement.  The Parties will meet and confer
    within three months of the Closing Date, as defined in the Purchase
    Agreement, regarding their respective methodologies.

4.3 Each Party has the right to audit the other Party's books and records by an
    independent Wirtschaftsprufer, at reasonable times and upon reasonable
    notice, solely for the purpose of confirmation of such Party's calculation
    of Costs.  Auditing shall be no more frequent than once a year.

4.4 If either Party believes that the costs of Services provided to it
    hereunder are substantially higher than the costs at which such Services
    generally are available, the Parties shall meet and confer to consider
    appropriate action.


Article 5 - Invoicing and Payment

The Parties' respective financial departments will negotiate reasonable and
appropriate
invoicing and payment terms including compensation for the time value of money.


Article 6 - Liability

6.1 Each Party shall monitor continuously whether the other Party is supplying
    Services in the agreed amount and quality.  Unless otherwise provided in
    the Annexes the following applies: Any incorrect amount and any obvious
    defect shall be notified in writing to the other Party promptly after
    detection. however no later than 30 (thirty) working days after the date on
    which the respective Service was rendered.  Other defects shall be notified
    in writing to the other Party promptly after detection,, however no later
    than 6 (six) months after the date on which the respective Service was
    rendered.  No Party is obliged to accept late notification of complaints.

6.2 The Parties shall only be liable for lack of diligence as applied in their
    own business (SORGFALT IN EIGENEN ANGELEGENHEITEN), Liability for
    consequential damages is hereby excluded.


<PAGE>

                                           8

6.3 In any case, liability of each Party for damages due to, or in connection
    with, Services supplied under this Agreement which are not in accordance
    with the requirements stipulated herein is limited to an amount of
    [CONFIDENTIAL TREATMENT REQUESTED] (in words: [CONFIDENTIAL TREATMENT
    REQUESTED]) per damaging event and to a total of [CONFIDENTIAL TREATMENT
    REQUESTED] (in words: [CONFIDENTIAL TREATMENT REQUESTED]) per calendar year,
    all to the extent legally possible. Such limits are not applicable to the 
    extent the damaging Party can recover compensation for such damages from 
    third parties including insurance companies.

6.4 Damages which amount with respect to a single damaging event to less than
    DM 5,000 (in words: Deutsche Mark five thousand) shall not be recoverable,
    provided that the aggregate amount of such small damages during one
    calendar year is not exceeding DM 25,000 (in words: Deutsche Mark
    twenty-five thousand).


Article 7 - Force Majeure

7.1 Unexpected interruptions in the operations of suppliers, unexpected delays
    in delivery or failure to make deliveries on the part of suppliers,
    strikes, lock outs, official restrictions and other eventualities which
    cannot reasonably be controlled or avoided by the respective Party ("Force
    Majeure") shall relieve such Party to the extent and for the duration of
    such event from its obligations under this Agreement and will not justify a
    claim for damages for any losses suffered by the other Party.

7.2 If a Party is forced to interrupt the supply of Services in whole or in
    part due to Force Majeure and if such situation is foreseeable, such Party
    shall inform the respective other Party promptly of the reasons for, and
    the expected extent and duration of, such interruption.  The Parties will
    make every reasonable effort to keep the negative effects of such an event
    as small as possible.

7.3 After an event of Force Majeure, the Parties shall agree amicably on how
    and to what extent Services not supplied are to be made up.

7.4 If the supply of Services is reduced owing to an event of Force Majeure,
    the respective Party will share the capacity it has available among its
    internal customers, the respective other Party and any other outside
    customers with respect to


<PAGE>

                                           9



         whom it has undertaken obligations, in accordance with the proportion
         of its Services previously accounted for by them.


Article 8 - Duration and Termination

8.1 This Agreement shall commence on the Contribution Date or in case the
    Operating Lease Agreement becomes effective upon the termination of the
    Operating Lease Agreement and shall run indefinitely, unless otherwise
    provided for in this Agreement.

8.2 Either Party may terminate this Agreement with immediate effect with regard
    to the relevant Service(s) if the other Party fails to observe significant
    obligations under this Agreement and does not, within a period of 60
    (sixty) days after having been warned by the other Party in writing to do
    so, return to a course of action which is in line with this Agreement and,
    as far as possible, remedy the infringement of this Agreement.

8.3 Either Party may terminate this Agreement with immediate effect if the
    other Party becomes insolvent or, in particular, if composition or
    insolvency proceedings are instituted with regard to its assets or if such
    procedures have been denied due to lack of assets.

8.4 Furthermore, each Party is entitled to terminate this Agreement, on a
    Service by Service basis, with respect to Services received by it by giving
    prior written notice of termination; provided that no such notice may be
    given before two years in case of category I Services or six months for any
    other Services, all after Closing Date as defined in the Purchase
    Agreement.

         Category I Services: two years prior written notice
         Category II Services: one year prior written notice
         Category III Services: six months prior written notice

8.5 In the event VuCo GmbH & Co. terminates in accordance with Art. 8.4 filling
    and packaging Services less than five years after the Closing Date as
    defined in the Purchase Agreement, and Behringwerke proves that it incurs,
    in connection with such termination, costs which cannot be eliminated even
    though Behringwerke uses its best efforts to reduce or eliminate such costs
    ("Residual


<PAGE>

                                           10



    Costs"), VuCo GmbH & Co. shall compensate Behringwerke for (i) in the first
    year after such termination becomes effective: 50% of such Residual Costs,
    (ii) in the second year: 25%, and (iii) in the third year: 12.5% of such
    Residual Costs.

8.6 In case a Party has - upon specific request of the other Party terminating
    this Agreement partially or entirely - made investments with regard to
    operations rendering Services to the other Party which it would not have
    made without such request, such other Party shall bear 100% of any Residual
    Costs after termination, until such Residual Costs have been completely
    reimbursed.

8.7 The Party claiming Residual Costs shall submit to the other Party a
    detailed record of such Residual Costs by the end of each calendar quarter.

8.8 The Residual Costs shall be invoiced separately for each month and shall
    become due and payable on the 15th day of the month  following the date on
    which the respective other Party receives such invoice.  Art. 4.3 shall
    apply MUTATIS MUTANDIS.

8.9 Any notice of termination of this Agreement, in its entirety or in part,
    shall only be valid if given in writing.

8.10     In case that either Party terminating Services wishes to establish its
         own functions with regard to such Services, it shall give priority to
         employees of the existing functions of the respective other Party.

8.11     Upon notice of termination of any Services hereunder, the Parties shall
         meet and confer regarding reasonable and appropriate steps to minimize
         the impact of such termination on remaining operations, in particular
         the possibility of gradually phasing out such Services over the course
         of the termination period.


Article 9 - Confidentiality

9.1 Any information whether written, oral or otherwise provided by a Party or a
    Party's sub-contractor to the other Party and any information obtained by a
    Party in connection with this Agreement, including the terms and conditions
    of this Agreement, shall be treated as confidential by the Party, receiving
    such information, shall only be used for purposes consistent with this
    Agreement and shall not


<PAGE>

                                           11

    be disclosed to any third party unless the Party or sub-contractor who
    provided such information has given its prior written consent to such other
    use or disclosure; provided, however, that each Party may disclose such
    information for purposes consistent with this Agreement to its employees,
    agents and sub-contractors, if any such employee, agent or sub-contractor
    agrees to keep such information confidential as if it were a party hereto.

9.2 The obligations of confidentiality, including the obligations of restricted
    use, shall continue for a period of ten years after the termination of this
    Agreement.

9.3 Excluded from the restrictions provided for in Art. 9.1 and 9.2 above is
    all information that has been disclosed by one Party or a sub-contractor to
    the other Party and which is:

    9.3.1     information that such other Party possessed in its own right
              before disclosure by the first Party or the sub-contractor;

    9.3.2     information that is in the public domain at the time of
              disclosure by a Party or a sub-contractor or has become part of
              the public domain through no fault of the other Party having
              received such information;

    9.3.3     information that such other Party has received, without
              restriction on its disclosure, legitimately from a third party
              not deriving the same from the Party or sub-contractor who made
              the original disclosure.

9.4 Information which is necessary for the enforcement of this Agreement or for
    compliance with applicable law, ordinances or orders of public authorities
    may be disclosed accordingly, provided that all reasonable steps are taken
    to preserve the confidentiality and the restricted use of such information.

9.5 All drawings, plans and other documents produced or commissioned by a Party
    or sub-contractor regarding any Service to be rendered shall remain the
    property of such Party or sub-contractor, unless agreement to the contrary
    has been reached.  Subject to Art. 9.3, such documents and any other
    confidential information received and any copies thereof shall be destroyed
    or returned upon request of the disclosing Party or sub-contractor or in
    the event of termination or rescission of this Agreement in total or in
    part.


<PAGE>

                                           12



Article 10 - Governing Law; Arbitration

10.1     This Agreement shall be governed by, and construed in accordance with,
         the law of the Federal Republic of Germany.

10.2     In case of any question or difference which may arise concerning the
         validity, construction, meaning or effect of this Agreement or
         concerning the rights and liabilities of the Parties hereunder or any
         matter arising out of, or in connection with, this Agreement cannot be
         amicably resolved, such question or difference shall be referred to,
         and determined by, an ad hoc arbitration tribunal of three arbitrators
         (the "Tribunal").

10.3     The arbitrators shall be appointed as follows:

    10.3.1    each party shall appoint one arbitrator, and the two arbitrators
              so appointed shall appoint a third arbitrator who shall be
              qualified to sit as a judge (Befahigung zum Richteramt) and who
              shall act as president of the Tribunal;

    10.3.2    if either Party fails to appoint its own arbitrator within
              twenty-one days of receipt of a written request by the other
              Party or if the two arbitrators are unable to jointly select a
              president within twenty-one days from the last appointment, such
              arbitrator or president shall be appointed by the President of
              the Court of Appeal of Frankfurt am Main (Prasident des
              Oberlandesgerichts) at the request of either Party.

10.4     The venue of such arbitration shall be Frankfurt am Main and the
         language shall be German.

10.5     The award of the Tribunal, which shall state the reasons for the
         decision, shall be final and binding upon the Parties.  The
         arbitrators shall have power to direct any interim measures.

10.6     With respect to aspects not expressly stipulated in this Art. 10, the
         arbitration shall be in accordance with the rules
         (Schiedsgerichtsordnung) of the Deutsche Institute for
         Schiedsgerichtswesen e.V.


<PAGE>

                                           13



Article 11 - Access to Behringwerke-Premises

11.1 With regard to the access to the Behringwerke-premises by employees of VuCo
     GmbH & Co. and/or third parties doing business with VuCo GmbH & Co. the
     following applies:

    11.1.1    At the entrance to the premises controls will be held in
              accordance with the Behringwerke-guidelines as amended from time
              to time.  To the extent technical appliances are required (e.g.,
              code cards), the specifications of which have to be agreed upon
              with Behringwerke, VuCo GmbH & Co. shall obtain such appliances
              at its own cost, to the extent possible by law.  It is VuCo GmbH
              & Co.'s responsibility that any orders of Behringwerke control
              personnel are followed and that the specific identification
              requirements imposed by Behringwerke under its guidelines are
              met.

    11.1.2    In order to meet the obligations hereunder, buildings, plants and
              parts of the Behringwerke-premises not expressly designated for
              such purpose may only be entered with the consent of
              Behringwerke.

11.2 VuCo GmbH & Co. undertakes to comply with the Behringwerke-guidelines, as
    applicable at any given time, to the use of its premises, in particular
    those regarding fire prevention, security or traffic in non-public areas.
    Such obligation is applicable also to VuCo GmbH & Co. personnel and to
    third parties doing business with VuCo GmbH & Co.; and VuCo GmbH & Co.
    shall inform such third parties of said obligations and guidelines.


Article 12 - Final Provisions

12.1 Unless otherwise defined herein, all terms shall have the same meanings and
    definitions as those in the Contribution Agreement.

12.2 Unless otherwise specifically amended hereby, all other terms of the
     Contribution Agreement shall remain in full force and effect.

12.3 Any rights of set-off (Aufrechnung) and/or retention (Zuruckbehaltung)
    based on claims for damages under this Agreement shall be excluded unless
    such claims


<PAGE>

                                           14



    are undisputed between the Parties or confirmed by a non-appealable
    court/arbitration decision.

12.4 Each Party may only assign this Agreement to a fully controlled affiliate
    which has the means to fulfill the obligations under this Agreement.

12.5 From time to time after the date hereof, at the request of either Party,
    the Parties shall execute and deliver to such requesting Party such
    documents and take such other action as such requesting Party may
    reasonably need in order to consummate more effectively the transactions
    contemplated hereby and to satisfy any legal requirements.

12.6 Any notification or amendment to this Agreement, including this Art. 12.6,
    must be in writing in order to be valid, unless more stringent requirements
    as to the form are stipulated by applicable law.

12.7 The Annexes hereto will become integral parts of this Agreement, and all
    references herein to this "Agreement" shall also include the Annexes.

12.8 To the extent possible, each provision of this Agreement will be
     interpreted in such manner as to be effective and valid under the
     applicable law.  If any provision of this Agreement is held to be
     prohibited by or invalid under applicable law, such provision will be
     ineffective only to the extent of such prohibition or invalidity, without
     invalidating the remainder of such provision or the remaining provisions
     of this Agreement. To the extent that a provision is ineffective or
     invalid, it shall be replaced by an effective and valid provision which
     comes as close as possible to the economic purpose of the ineffective or
     invalid provision.


________________,this ___ day of _______,1996.


BEHRINGWERKE AG                             [VuCo GmbH & Co.]


- -----------------------------------         ---------------------------------
By:                                         By:
Title:                                      Title:


<PAGE>

                                                                      ANNEX 11.2
                                                   to the Contribution Agreement



LEASE AGREEMENT

between



Behringwerke AG
35001 Marburg

- - hereinafter "Behringwerke" -


and


- ------------------------


- ------------------------

- - hereinafter "VuCo GmbH & Co." -


<PAGE>

                                        2


                                TABLE OF CONTENTS

Preamble                                                                     4

Article 1 - Object of Lease                                                  4

Article 2 - Term of Lease                                                    5

Article 3 - Rent                                                             5

Article 4 - Ancillary Costs                                                  6

Article 5 - Value Added Tax                                                  8

Article 6 - Condition of the Premises                                        8

Article 7 - Liability, Encumbrances, Responsibility                          8

Article 8 - Insurance                                                        9

Article 9 - Use of Premises                                                 10

Article 10 - Maintenance and Repairs                                        12

Article 11 - Destruction of Premises                                        12

Article 12 - Structural Changes by Behringwerke                             13

Article 13 - Assignment and Subletting                                      13

Article 14 - Change of legal entity, Sale of Business                       14

Article 15 - Signs                                                          14

Article 16 - Indemnification                                                14

Article 17 - Default, Termination                                           15

Article 18 - Hazardous Materials                                            17

Article 19 - Force Majeure                                                  18

Article 20 - Confidentiality                                                18



<PAGE>

                                        3


Article 21 - Arbitration                                                    19

Article 22 - Final Provisions                                               20



<PAGE>

                                        4

                                    PREAMBLE

Pursuant to the Contribution Agreement to which this Lease Agreement is an
annex, Behringwerke is contributing its human vaccine unit (the "Business") to
VuCo GmbH & Co. VuCo GmbH & Co. intends, for the foreseeable future, to conduct
the Business within the premises of Behringwerke on a lease basis.

Therefore, the parties hereto agree as follows:

ARTICLE 1 - OBJECT OF LEASE

1.1  Behringwerke hereby leases to VuCo GmbH & Co. and VuCo GmbH & Co. hereby
     leases from Behringwerke certain parcels rentable land offices space,
     production facilities including fixtures and integral parts (WESENTLICHE
     BESTANDTEILE) within Behringwerke's Marburg sites which are particularly
     described and fully enumerated in ANNEX 1.1, (a) and marked in black in
     ANNEX 1.1, (b) (the "Premises"). Under this lease, VuCo GmbH & Co. is also
     entitled to enter and use common areas (GEMEINFLACHEN), designated access
     and delivery areas, if any, waste disposal facilities and access to ingress
     and egress of the site, to parking spaces, and to the cafeteria, subject to
     Behringwerke-guidelines which shall be exercised by Behringwerke in
     accordance with sect. 315 et seq. Civil Code (BGB).

1.2  The Premises shall be occupied and used by VuCo GmbH & Co. for the business
     of human health care and shall not be used for any other purpose whatsoever
     without the prior written consent of Behringwerke, which shall not be
     unreasonably withheld.

     Any consent by Behringwerke, even if not explicitly stated, shall always be
     granted subject to all official authorizations as may be required for the
     envisaged change of the use of the Premises. Upon request, VuCo GmbH & Co.
     shall provide Behringwerke with proof that all necessary official
     authorizations have been duly granted.

1.3  The supply of utilities and services such as electricity, water etc. by
     Behringwerke and VuCo GmbH & Co.'s obligation to receive, and pay for, any
     such utilities and services are specifically settled in the Master Service
     Agreement.

ARTICLE 2 - TERM OF LEASE

2.1  The Lease shall commence on the Contribution Date or, in case the Operating
     Lease Agreement (BETRIEBSPACHTVERTRAG) becomes effective, upon termination
     of the Operating 


<PAGE>

                                        5


     Lease Agreement (the "Closing Date"). The initial term of the lease shall
     be five years (the "Initial Term"). VuCo GmbH & Co. shall have the right in
     its discretion to extend the lease for an additional five years (the
     "Extension Period") by providing written notice to Behringwerke no later
     than March 31, 2001.

     During the Extension Period, VuCo GmbH & Co. shall have the right to
     terminate the lease in whole or in certain parts of the Premises upon six
     months' prior written notice to Behringwerke. During the Initial Term, VuCo
     GmbH & Co. shall have the right to terminate the lease in part (but not in
     whole) upon six months' prior written notice to Behringwerke, PROVIDED THAT
     such right of early termination shall not apply to Premises used for
     manufacturing including quality control. 

     In case Behringwerke undertook capital investments related to the Premises
     in the Extension Period on specific written request of VuCo GmbH & Co. and
     VuCo GmbH & Co. terminates this Agreement under the foregoing sentence,
     VuCo GmbH & Co. shall reasonably compensate Behringwerke therefore.

2.2  Section 568 German Civil Code (Section 568 BGB) shall not apply upon expiry
     of the term of the Lease.

ARTICLE 3 - RENT

3.1  As of the Closing Date VuCo GmbH & Co. shall pay to Behringwerke as annual
     rent an amount to be calculated on the basis of present lease agreement
     agreed between Behringwerke and Hoechst but in no case more than fair
     market value. For this purpose VuCo GmbH & Co. has the right to audit
     Behringwerke books and records of an independent Wirtschaftsprufer
     acceptable for Behringwerke at reasonable times and upon reasonable notice
     solely for the purpose of confirmation of such Party's calculation of
     costs. Auditing shall be no more frequent than once a year.

     In case the Parties cannot agree on the fair market rent either Party is
     entitled to request the President of the chamber of commerce of Frankfurt
     to nominate an expert who shall resolve such matter to be binding upon the
     Parties. The costs shall be borne pursuant to sec. 91 et seq. Civil
     Procedure Code (ZPO). 

3.2  The Rent shall be due and payable in equal quarterly installments in
     arrears on January 10, April 10, July 10 and October 10 of each year
     (the"Rent Payment Dates").


<PAGE>

                                        6



3.3  Payments are to be made to a bank account named by Behringwerke in time to
     be received at the respective Rent Payment Date. Late payment shall bear
     interest at a rate of three percentage points above the relevant discount
     rate of the German Federal Bundesbank.

ARTICLE 4 - ANCILLARY COSTS

4.1  In addition to the Rent VuCo GmbH & Co. shall bear certain ancillary costs.
     Behringwerke AG shall use it best efforts to attribute the ancillary costs
     as to the various buildings and to the various tenants. Only insofar as the
     ancillary costs can not be attributed to specific buildings and/or specific
     tenants the ancillary costs shall be allocated to all tenants, where
     appropriate, on the basis of squarmeters rented, or on such other criteria
     which is reasonable for the allocation of those costs among the various
     users. Costs having been considered in calculating any fee under the Master
     Service Agreement shall not be escalated to VuCo GmbH & Co. Ancillary costs
     are:

     4.1.1     expenses of cleaning, lightning, repairing, renewing, decorating,
               maintaining and rebuilding any walls, fences, gutters, drains,
               road ways, pavements, access ways, service areas and any other
               common areas of the Premises which are or may be used or enjoyed
               by VuCo GmbH & Co. in common with any other person or persons;

     4.1.2     any insurance premiums payable by Behringwerke for insuring the
               Premises or any part thereof; 

     4.1.3     all running expenses as defined in Appendix 3 to Section 27,
               subsection 1, of the second computation order (Anlage 3 zu
               Section 27 Abs. 1 der zweiten Berechnungsverordnung).

4.2  To the extent it is not possible for legal or factual reasons that VuCo
     GmbH & Co. pay such costs and expenses directly and in its own name, VuCo
     GmbH & Co. will reimburse to Behringwerke such costs at the respective due
     date.

4.3  The costs referred to in Art. 4.1 shall be invoiced by the end of February
     of each year, at the latest, for the respective preceding year.

     VuCo GmbH & Co. shall make quarterly down-payments regarding the costs
     referred to in Art. 4.1 amounting to one quarter of the budgeted ancillary
     costs for this year. Any difference between the down-payments for a
     calendar year and the respective invoice shall 


<PAGE>

                                        7


     be settled between the parties by a single payment payable one month after
     receipt of the annual invoice pursuant to this Art. 4.3.  

4.4  Behringwerke shall adjust the quarterly down-payment in its reasonable
     discretion in accordance with Section 315 BGB if circumstances affecting
     such payments should change. This adjusted down-payment shall become
     payable as of the Rent Payment Date following receipt of the relevant
     written notice.

ARTICLE 5 - VALUE ADDED TAX

All amounts owed hereunder are net, i.e. without Value Added Tax (VAT;
UMSATZSTEUER). If a payment is subject to VAT, such tax shall be paid in
addition against presentation of an invoice in accordance with the requirements
pursuant to Section 14 VAT Act (Section 14 UMSATZSTEUERGESETZ).

ARTICLE 6 - LIABILITY, ENCUMBRANCES, RESPONSIBILITY

From the Closing Date VuCo GmbH & Co. shall be responsible for the safe
condition of the Premises including VuCo GmbH & Co.'s equipment and attachments,
whether internal or external, and for the safe operation of the Business.
Furthermore, VuCo GmbH & Co. shall fully comply with all applicable laws,
regulations, rules, ordinances and requirements, including environmental laws,
of any governmental authority having jurisdiction over the Premises or the
Business.

ARTICLE 7 - INSURANCE

7.1  Notwithstanding any other provision of this Agreement, insurance with
     respect to the Premises shall be maintained to the extent reasonable as
     follows:

     7.1.1     Behringwerke agrees to purchase, maintain and keep in force
               during the term of this Agreement, insurance against damage or
               destruction as result of risks as are for the time being
               reasonably required to be covered such as fire, lightning,
               explosion, riot, civil commotion, acts of terrorism, aircraft and
               other aerial devices or articles dropped therefrom (other than
               war risks), storm, flood and burst pipes in a sum equal to the
               full reinstatement costs of the Premises and fixtures, equipment
               and personal property contained therein, including the costs of
               demolition, shoring up and site clearance and all architect's,
               surveyor's and other professional fees and incidental expenses in
               connection with reinstatement and business interruption insurance
               covering the Premises. Such policies shall (i) name VuCo GmbH &
               Co. as an additional insured and, with respect to business
               interruption insurance, as a loss 


<PAGE>

                                        8


               payee, and (ii) provide that said insurances shall not be
               cancelled unless 30 (thirty) day's prior written notice shall
               have been given to VuCo GmbH & Co.

     7.1.2     VuCo GmbH & Co. agrees to purchase, maintain and keep in force
               during the term of this Agreement, a comprehensive general
               liability insurance policy and such further insurance or
               insurances which are necessary in respect of the Business. Such
               policies shall (i) name Behringwerke as an additional insured,
               and (ii) provide that said insurances shall not be cancelled
               unless thirty (30) days' prior written notice shall have been
               given to Behringwerke. For purposes of any general liability
               claims made in respect of the Premises, VuCo GmbH & Co.'s
               comprehensive general liability policy will be primary, and
               Behringwerke's will be secondary.

7.2  Upon request, each party shall deliver to the other certificates evidencing
     insurance coverage upon the Closing Date and upon each renewal of said
     insurances.

7.3  VuCo GmbH & Co. and Behringwerke each agree that to the extent reasonably
     possible the respective insurance carried by it against loss or damage by
     fire or other casualty shall contain a clause whereby the insurer waives
     its rights of recourse against the other party.

     Pursuant to the foregoing, Behringwerke and VuCo GmbH & Co. hereby waive
     all claims for recovery from the other party for any loss or damage to any
     of its property insured under valid and collectible insurance policies to
     the extent of any recovery collectible under such insurance. The foregoing
     waiver shall be in force only if such VuCo GmbH & Co.'s and Behringwerke's
     insurance policies contain a clause providing that such waiver shall not
     invalidate the insurance.

7.4  If either Party fails to comply with its obligation to insure then, without
     prejudice to its other remedies, the other party may effect and maintain
     the relevant insurance and the premium and other costs of so doing
     (including without limitation the cost of obtaining any insurance
     valuations) shall be paid by the party failing to take such insurance.

ARTICLE 8 - USE OF PREMISES

8.1  VuCo GmbH & Co. shall only use the Premises or any part thereof in
     accordance with the terms of this Agreement and like a diligent businessman
     in the pharmaceutical business and shall comply with all legal requirements
     and authorizations and security guidelines of Behringwerke. 

8.2  VuCo GmbH & Co. shall not do anything that would unreasonably impair or
     interfere with or tend to impair or interfere with any activities of
     Behringwerke or any other party on the Marburg sites. VuCo GmbH & Co. shall
     install at VuCo GmbH & Co.'s expense all equipment, safety 


<PAGE>

                                        9


     device, pollution control systems or other installations required at any
     time with regard to the Business. The foregoing shall apply MUTATIS
     MUTANDIS to Berhingwerke. Further Behringwerke shall use its best efforts
     that no unreasonable impairment of or interference with the Business is
     caused by other tenants of the Behringwerke site in Marburg.

8.3  Behringwerke warrants that as of the date hereof applicable zoning and land
     use law permits the use of the Premises as described in Art. 1.2. VuCo
     GmbH & Co. is responsible to maintain in place all permits required by law,
     regulation, ordinance or other requirement of any governmental authority
     with respect to the operation of the Business, except to the extent that
     only Behringwerke may obtain such permits or to the extent that such
     permits are required for common areas or entire buildings in which VuCo
     GmbH & Co.'s portion of the Premises is less than 100%, in which event
     Behringwerke must obtain such permits. The costs for such permits shall be
     apportioned between the users of these buildings equal to their portion of
     the area (FLACHENANTEIL) of the buildings.

8.4  VuCo GmbH & Co. shall not make any material alterations, improvements, or
     additions of or to the Premises (collectively the "Alteration") without
     first submitting to Behringwerke plans and specifications therefor and
     obtain Behringwerke's prior written consent in each and every instance,
     which consent shall not be unreasonably withheld or delayed. All
     alterations made by VuCo GmbH & Co. shall be at the expense and the sole
     risk of VuCo GmbH & Co. 

8.5  Before installing any heavy objects, VuCo GmbH & Co. shall ascertain from
     Behringwerke the bearing capacity of the floors. The authorized bearing
     capacity (in absolute terms and per square meter) may not be exceeded,
     otherwise VuCo GmbH & Co. shall be liable for all damage caused thereby and
     shall reimburse Behringwerke in respect of any claims resulting therefrom.

8.6  Appliances and installations may only be connected to the existing mains,
     and operated, in accordance with the mains' capacity. No interferences must
     be caused by such appliances and installations. VuCo GmbH & Co. shall
     inform itself about the capacity not be exceeded. VuCo GmbH & Co. shall
     bear the cost of any alterations or new installations of the mains or other
     supply or disposal pipes necessary due to VuCo GmbH & Co.'s operations.
     Behringwerke, however, assures to its best knowledge that the mains in
     place are sufficient for the Business as currently conducted. 


<PAGE>

                                       10


ARTICLE 9 - MAINTENANCE AND REPAIRS

9.1  VuCo GmbH & Co. is responsible for proper servicing, maintenance and repair
     of the Premises and shall maintain the Premises in good order and repair,
     as required by law, necessary to ensure the safety and health of all
     persons on the Premises.

9.2  Behringwerke is responsible for repairs of all common areas and of such
     parts of buildings which, while not being part of the Premises, are
     necessary for the Premises being used in accordance with the terms of this
     Agreement. Further all necessary works and repairs which have to be
     capitalized shall be performed by Behringwerke.  

9.3  VuCo GmbH & Co. shall only be excused of its obligation to pay rent if
     Behringwerke, having been requested by VuCo GmbH & Co. in writing with
     reasonable notice to do so, has not met its obligation under Art. 9.2 and
     such failure renders the affected portion of the Premises unusable for 5
     (five) consecutive days. After such 5 (five) day period VuCo GmbH & Co.
     will not be obligated to pay rent for such portion until such time as such
     portion is repaired and returned to usable condition in compliance with all
     relevant laws, regulations and administrative orders.

ARTCLE 10 - DESTRUCTION OF PREMISES

10.1 If the Premises or any part thereof are severely damaged or destroyed to an
     extent that repair is likely to create costs in excess of 40 % of its
     current partial value (TEILWERT) ("Damaged Property"), VuCo GmbH & Co.
     shall give immediate notice thereof to Behringwerke and shall enable
     Behringwerke to immediately assess the damages.

10.2 If Behringwerke determines, following its assessment of the damage which
     has occurred, that the Damaged Property cannot be repaired or
     reconstructed, as the case may be, within a reasonable period or with
     reasonable efforts and expenses (in either circumstance, the "Loss Event")
     the parties shall use their best efforts to agree on an adequate solution
     acceptable to both parties. If the parties fail to agree within two months
     of the Loss Event Behringwerke may elect not to repair or reconstruct the
     Damaged Property and may thereupon terminate this Agreement with regard to
     the respective part of the Premises delivering to VuCo GmbH & Co. notice
     of such election.  In such event, the rent shall be reduced
     proportionately. VuCo GmbH & Co. can terminate the lease if the remaining
     Premises are insufficient for the Business and Behringwerke cannot provide
     for a reasonable alternative. In case the Damaged Property is not repaired
     or reconstructed, Behringwerke shall be entitled to all payments made by
     insurers with respect to the Damaged Property.


<PAGE>

                                       11

ARTICLE 11 - STRUCTURAL CHANGES BY BEHRINGWERKE


11.1 Behringwerke may, even without VuCo GmbH & Co.'s consent, carry out any
     improvements or structural changes necessary or expedient to maintain,
     preserve, modernize or expand the Premises, to eliminate imminent danger,
     or to repair defects. In such case, Behringwerke shall reasonably take into
     account the interests of VuCo GmbH & Co. VuCo GmbH & Co. shall allow
     Behringwerke reasonable access to the Premises at reasonable times and
     shall not obstruct or delay the execution of the work.

11.2 VuCo GmbH & Co. shall only be entitled to make claims against Behringwerke
     because of any work carried out pursuant to Art. 11.1 if VuCo GmbH & Co.'s
     activities have been considerably impaired thereby for more than 5 (five)
     consecutive days. 

ARTICLE 12 - ASSIGNMENT AND SUBLETTING

12.1 VuCo GmbH & Co. is only entitled to assign or transfer all or any of its
     rights, benefits and obligations under this Agreement to affiliates (as
     defined in sec. 15 et seq. Stock Corporation Act - AKTIENGESETZ) of Chiron
     Corporation. Any other assignment or sublet needs the prior written consent
     of Behringwerke which consent shall not be unreasonably withheld.
     Behringwerke is only entitled to assign all or any of its rights, benefits
     and obligations under this Agreement to affiliates (as defined in Sec. 15
     et.seq. Stock Corporation Act - AKTIENGESETZ) of Hoechst AG. Any other
     assignment by Behringwerke needs the prior written consent of VuCo GmbH &
     Co. which consent shall not be unreasonably withheld.

12.2 In the event of subtenancy, VuCo GmbH & Co. shall be absolutely liable for
     all acts and omissions of the sub-tenant.

12.3 In the event of subtenancy, VuCo GmbH & Co. hereby and as of now assigns to
     Behringwerke as security all claims, including any accompanying liens which
     it may have against the sub-tenant.

ARTICLE 13 - CHANGE OF LEGAL ENTITY, SALE OF BUSINESS

13.1 VuCo GmbH & Co. must notify Behringwerke immediately of any change in
     control of VuCo GmbH & Co. or of its intention to sell or close the
     Business or any material part thereof.

13.2 In case of the sale of VuCo GmbH & Co.'s business or a part thereof, buyer
     has no claim to have this Agreement assigned to him.


<PAGE>

                                       12


ARTICLE 14 - SIGNS

     Subject to all applicable zoning or regulatory requirements, VuCo GmbH &
     Co. may install at its own expense and after obtaining any necessary
     permits and Behringwerke's approval (which shall not be unreasonably
     withheld) appropriate monument signs at the entrance to the Premises which
     in any event may be comparable in number, size and overall impact to the
     monuments of Behringwerke in the same or similar locations and appropriate
     additional exterior signs on the buildings; provided, however, that upon
     termination of this Agreement VuCo GmbH & Co. shall remove said sign(s) and
     repair damages caused thereby. 

ARTICLE 15 - INDEMNIFICATION

15.1 VuCo GmbH & Co. will indemnify, defend and hold Behringwerke and its
     shareholders, subsidiaries, affiliates, officers, directors, agents and
     employees harmless from and against any claims, costs, liabilities, fines,
     damages or expenses (including reasonable attorney's fees) arising from or
     alleged to arise from or out of VuCo GmbH & Co.'s operations or from or out
     of an act, omission, fault, negligence or other misconduct of VuCo GmbH &
     Co., its agents, ser-vants, employees, visitors or contractors with or at
     the areas of the Premises over which VuCo GmbH & Co. has control occurring
     after the Closing Date, except arising out of Behringwerke's gross
     negligence.

15.2 Behringwerke will indemnify, defend and hold VuCo GmbH & Co. and its
     general and limited partners, subsidiaries, affiliates, officers,
     directors, agents and employees harmless from and against any claims,
     costs, liabilities, fines, damages or expenses (including reasonable
     attorney's fees) arising from or alleged to arise from or out of
     Behringwerke's operations or from or out of an act, omission, fault,
     negligence or other misconduct of Behringwerke, its agents, servants,
     employees, visitors or contractors on the Premises or the Marburg sites,
     except arising out of VuCo GmbH & Co.'s gross negligence.

15.3 To the extent the mutual obligations pursuant to Art. 15.1 and 15.2 exceed
     the statutory liability, such obligations shall apply only if approved by
     the respective insurance companies.

15.4 Neither Party shall be responsible for consequential damage hereunder.

ARTICLE 16 - DEFAULT, TERMINATION

16.1 The statutory provisions, except Section 554 German Civil Code (Section 554
     BGB), shall apply for the termination of the Lease for serious cause.


<PAGE>

                                       13



16.2 Behringwerke may terminate the Lease without notice in particular if one or
     more of the following events of default occur during the term of this
     Agreement:

     16.2.1    VuCo GmbH & Co. fails to pay any regular instalment of Rent
               and/or ancillary costs when due and such default continues for 15
               (fifteen) days upon receipt of a written notice from
               Behringwerke, provided Behringwerke needs not furnish more than 2
               (two) such notices in any calendar year; or

     16.2.2    VuCo GmbH & Co. defaults in the performance of any other
               requirement, obligation or covenant of this Agreement and any
               such failure continues for 30 (thirty) days after notice thereof
               from Behringwerke (excepting, however, any default which is not
               reasonably susceptible of cure within said period of 30 (thirty)
               days and which VuCo GmbH & Co. shall in good faith and with due
               diligence be proceeding to cure); or

     16.2.3    bankruptcy or composition proceedings are instituted against VuCo
               GmbH & Co. or if a petition in bankruptcy filed by VuCo GmbH &
               Co. is dismissed for lack of assets; or

     16.2.4    the interest of VuCo GmbH & Co. in the Premises is taken upon
               execution or by other process of law directed against VuCo GmbH &
               Co., or taken upon or subjected to any attachment by any creditor
               of VuCo GmbH & Co. or claimant against VuCo GmbH & Co., and such
               attachment is not discharged within 15 (fifteen) days.

16.3 VuCo GmbH & Co. may also terminate the Lease if the Business cannot be
     operated on the Premises due to public law; provided that VuCo GmbH & Co.
     shall use reasonable efforts to avoid the applicability of such law,
     including obtaining a waiver.

16.4 VuCo GmbH & Co. hereby grants to Behringwerke full and free right to enter
     into and upon the Premises in such event as permitted by law, to repossess
     the Premises and to remove objects belonging to VuCo GmbH & Co.

16.5 Any and all objects in the possession of VuCo GmbH & Co. at termination of
     the lease (irrespective of ownership) or to which VuCo GmbH & Co. has a
     claim, may be removed and/or stored at the discretion of Behringwerke at
     the risk, cost and expense of VuCo GmbH & Co. VuCo GmbH & Co. shall pay to
     Behringwerke, upon demand any and all expenses incurred in such removal and
     all storage charged against such property so long as the same shall be in
     Behringwerke's possession or control. Any such objects not retaken by VuCo
     GmbH & Co. from storage within 40 (forty) days after removal from the
     Premises may be sold (VERWERTET) by 


<PAGE>

                                       14



     Behringwerke without restrictions. The proceeds less any and all costs and
     claims by Behringwerke shall be paid to VuCo GmbH & Co.

16.6 On termination of the Lease, whether in accordance with this Art. 16 or
     Art. 2 of this Agreement, VuCo GmbH & Co. shall immediately surrender the
     Premises, and deliver possession thereof to Behringwerke, properly
     renovated and repaired. This shall include: all repairs pursuant to
     Art. 10.1, renewal of the floor coverings and wall paper, painting of
     radiators and heating pipes, as well as of doors, window frames and door
     frames, all at least to the standard as of the Closing Date. Should VuCo
     GmbH & Co. surrender the Premises without having carried out the work
     described above, Behringwerke may carry out all necessary work at VuCo
     GmbH & Co.'s expense. Behringwerke's claim in respect of the costs thereby
     incurred shall also subsist if these works are carried out by the
     subsequent tenant.

ARTICLE 17 - HAZARDOUS MATERIALS

17.1 Hazardous materials or material to be monitored (UBERWACHUNGSBEDURFTIG) or
     waste as defined by the applicable laws, regulations and administrative
     orders relating to chemicals, hazardous materials and waste (CHEMIKALIEN-,
     GEFAHRSTOFF- UND ABFALLRECHT) may only be stored, handled, treated,
     disposed of, discharged, produced, processed or used by VuCo GmbH & Co.
     anywhere in or on the Premises or the common areas with the prior written
     consent of Behringwerke and in full compliance with all applicable laws,
     regulations and administrative orders. Such consent shall not unreasonably
     be withheld. Such consent of Behringwerke is not required for the use of
     such hazardous materials or material to be monitored or waste as are
     currently in use or being created on the Premises. VuCo GmbH & Co. shall
     keep and maintain updated material safety data sheets (or similar documents
     required by law) and shall make them available for Behringwerke's
     inspection upon request.

17.2 Each of Behringwerke and VuCo GmbH & Co. shall (i) promptly notify the
     other of any complaints, notice or other correspondence received from any
     third party concerning any actual or alleged violation of any applicable
     law, regulation or administrative order regarding hazardous materials,
     material to be monitored or waste; (ii) promptly notify the appropriate
     public body in case of any emission, release, leakage or emergency of any
     kind (STORFALL).

17.3 VuCo GmbH & Co.'s responsibilities, covenants and liabilities under this
     Art. 17 shall survive the expiration or earlier termination of this
     Agreement. Any events arising from acts or omissions occurring prior to the
     Closing Date are the responsibility of Behringwerke.


<PAGE>

                                       15


ARTICLE 18 - FORCE MAJEURE

     Neither party shall be responsible for delays or inability to perform its
     obligations hereunder due to force majeure or for other causes beyond the
     reasonable control of such party including acts of other tenants,
     governmental restriction, regulation or control, labor dispute, accident,
     mechanical breakdown, shortages or inability to obtain labor, fuel, steam,
     water, electricity or materials, acts of God, enemy action, civil commotion
     or fire or other casualties.

ARTICLE 19 - CONFIDENTIALITY

19.1 Any information whether written, oral or otherwise provided by a party to
     the other party and any information obtained by a party in connection with
     this Agreement, including the terms and conditions of this Agreement, shall
     be treated as confidential by the party receiving such information, shall
     only be used for purposes consistent with this Agreement and shall not be
     disclosed to any third party unless the party who provided such information
     has given its prior written consent to such other use or disclosure;
     provided, however, that each party may disclose such information for
     purposes consistent with this Agreement to its employees, agents and sub-
     contractors, if such employee, agent or sub-contractor agrees to keep such
     information confidential as if it were a party hereto.

19.2 The obligations of confidentiality, including the obligations of restricted
     use, shall continue for a period of ten years after the termination of this
     Agreement. 

19.3 Excluded from the restrictions provided in Art. 19.1 and 19.2 above is all
     information that has been disclosed by one party to the other party and
     which is:

     19.3.1    information that such other party possessed in its own right
               before disclosure by the first party;

     19.3.2    information that is in the public domain at the time of
               disclosure by a party or has become part of the public domain
               through no fault of the other party having received such
               information;

     19.3.3    information that such other party has received, without
               restriction on its disclosure, legitimately from a third party
               not deriving the same from the party who made the original
               disclosure.

19.4 Information which must be disclosed in order to comply with any laws,
     regulations or administrative or court orders may only be disclosed to the
     entities named in such laws, 


<PAGE>

                                       16


     regulations or orders. Prior to such disclosure, the other party must be
     informed about the nature, extent and contents of the information to be
     disclosed.

ARTICLE 20 - LAW; VENUE

This Agreement shall be governed by, and construed in accordance with, the law
of the Federal Republic of Germany. The arbitration clause in the Contribution
Agreement shall not be applied.

ARTICLE 21 - FINAL PROVISIONS

21.1 Behringwerke, his agents or representatives shall, upon giving prior
     notice, be entitled to inspect the Premises during VuCo GmbH & Co.'s normal
     business hours and at reasonable intervals. In the event of a release or
     other environmental emergency or any other emergency at the Premises
     Behringwerke shall have the right to enter the Premises for purposes of
     responding to such release or emergency at any time without giving VuCo
     GmbH & Co. notice in advance.

21.2 The access to the Premises shall be governed by Art. 11 of the Master
     Service Agreement.

21.3 VuCo GmbH & Co. may only set-off (AUFRECHNUNG), and exercise rights of
     retention (ZURUCKBEHALTUNG), regarding claims against the rent or ancillary
     costs if these claims are undisputed between the parties or acknowledged by
     Behringwerke or confirmed by a non-appealable decision.

21.4 Any amendment, cancellation or supplement of a provision of this Agreement,
     including this Art. 21.4 and any notification under this Agreement must be
     in writing in order to be valid, unless more stringent requirements as to
     the form are stipulated by the applicable law.

21.5 This Agreement embodies the entire agreement between the parties hereto
     with regard to the subject matter hereof and there have been no agreements,
     representations or warranties between the parties with regard to the
     subject matter hereof other than those set forth or provided for herein.

21.6 The Annexes hereto are integral parts of this Agreement, and all references
     herein to this "Agreement" shall also include the Annexes.

21.7 If any provision of this Agreement is held to be prohibited by or invalid,
     such provision will be ineffective only to the extent of such prohibition
     or invalidity, without invalidating the remainder of such provision or the
     remaining provisions of this Agreement. To the extent that a provision is


<PAGE>

                                       17


     ineffective or invalid, it shall be replaced by an effective and valid
     provision which comes as close as possible to the economic purpose of the
     ineffective or invalid provision.

__________, this ___ day of __________, 1996


BEHRINGWERKE AG                         [VuCo GmbH & Co.]

______________________________          ______________________________
By:                                     By:
Title:                                  Title:


<PAGE>

Annex 1.1.(a) to Lease Agreement


<TABLE>
<CAPTION>

- ------------------------------------------------------------------------------
                                               Usage by Vaccine Unit
                                   -------------------------------------------
                                                                           2
Building                              %                                   m
- ------------------------------------------------------------------------------

<S>                                <C>                                    <C>
H 6                                 19,5                                   663
- ------------------------------------------------------------------------------
H 10                                30,0                                  1058
- ------------------------------------------------------------------------------
H 12                                61,0                                  2312
- ------------------------------------------------------------------------------
H 15                                51,0                                     ?
- ------------------------------------------------------------------------------
Z 20                                 6,0                                    33
- ------------------------------------------------------------------------------
Z 21                                40,0                                   690
- ------------------------------------------------------------------------------
Z 25                                 6,2                                   404
- ------------------------------------------------------------------------------
Z 26/30                             19,9                                  1287
- ------------------------------------------------------------------------------
H 33                                49,9                                  1205
- ------------------------------------------------------------------------------
H 38                                25,8                                    66
- ------------------------------------------------------------------------------
M 544                               10,0                                    49
- ------------------------------------------------------------------------------
H 70                                 0,3                                     ?
- ------------------------------------------------------------------------------
H 11                                75,0                                  1734
- ------------------------------------------------------------------------------
H 21                                50,0                                  2727
- ------------------------------------------------------------------------------
H 26                               100,0                                  1565
- ------------------------------------------------------------------------------
H 28                                75,0                                  5400
- ------------------------------------------------------------------------------
H 32                                66,0                                   515
- ------------------------------------------------------------------------------
H 34                                80,0                                   317
- ------------------------------------------------------------------------------
M 218                               40,0                                   592
- ------------------------------------------------------------------------------
M 537                              100,0                                  1440
- ------------------------------------------------------------------------------
</TABLE>


<PAGE>

                                              ANNEX 1.4 (b)
                                  TO THE PURCHASE AGREEMENT


                          PARTNERSHIP AGREEMENT
                                   OF
                  CHIRON BEHRING BIOCINE GmbH & CO. KG
                 (FORMER: BEHRING VAKZINE GmbH & CO. KG)

                                 BETWEEN
                             BEHRINGWERKE AG
                                   AND
        32.  CORSA VERWALTUNGSGESELLSCHAFT mbH ("32.CORSA GmbH")
                                   AND
        31.  CORSA VERWALTUNGSGESELLSCHAFT mbH ("31.CORSA GmbH")


In consideration of the Purchase and Assignment Agreement between
Behringwerke AG and 31. Corsa GmbH (the "Purchase Agreement"), the
Contribution Agreement between Behring Vakzine GmbH & Co KG and Behringwerke
AG and the Shareholders' Agreement between Behringwerke and 3 1. Corsa GmbH.
the Parties to this Agreement agree to the following terms of their
partnership:


  1.  NAME, REGISTERED OFFICE

      1.1   The name of the Partnership shall be

                  CHIRON BEHRING BIOCINE GmbH & CO. KG

      1.2   The Partnership has its registered office in Marburg.



  2.  PURPOSE OF THE PARTNERSHIP

      2.1   The purpose of the Partnership is the development, production and
            distribution of pharmaceutical products, in particular human
            vaccines.

<PAGE>
                                     2


      2.2   The Partnership is entitled to take all actions which are necessary
            or appropriate to further the purpose of the Partnership directly or
            indirectly.

      2.3   The Partnership is entitled to establish other enterprises and
            branches within Germany and other countries or to acquire other
            business enterprises, including partnerships, thereon.


  3.  PARTNERS; PARTNERSHIP CAPITAL

      3.1   The General Partner is 32.Corsa GmbH.  The General Partner does not
            make a capital contribution and does not participate in the capital
            of the Partnership.

      3.2   The Limited Partners of the partnership are

            3.2.1     Behringwerke AG with a partnership interest of 51%

            3.2.2     31. Corsa GmbH with a partnership interest of 49%.


      3.3   The capital of the Partnership has been or will be contributed in
            kind by Behringwerke AG pursuant to be Contribution
            Agreement prior to the transfer of the 49% interest in the 
            Partnership pursuant to the Purchase Agreement. The capital 
            contribution of Behringwerke under the Contribution Agreement is 
            fixed and may not be withdrawn.

      3.4   The capital contribution of the Limited Partners to be registered in
            the commercial register (Hafteinlage) shall be:

            3.4.1     Behringwerke AG DM 2,550,000 (in words: Deutsche
                      Mark two million five hundred fifty thousand)

            3.4.2     31. Corsa GmbH DM 2,450,000 (in words: Deutsche
                      Mark two million four hundred fifty thousand)


<PAGE>

                                    3



      3.5   The capital accounts I and II determine the interest of each of the
            Partners in the Partnership ("Partnership Interest").


  4.  PARTNER ACCOUNTS

      4.1   For each partner,a capital account I, a capital account II, a
            reserve account, a loss carry forward account and a transaction
            account shall be maintained.

      4.2   The contribution to be registered in the commercial register
            shall be booked into the capital account I of each of the Limited
            Partners.  This capital account is fixed.  Pursuant to the
            Contribution Agreement Behringwerke has contributed DM 5,000,000
            (in words: Deutsche Mark five million) in kind to the capital
            account I of Behringwerke, of which 49 % will be transferred to
            the capital account I of 31. Corsa GmbH.

      4.3   The remainder of the capital contribution of Behringwerke in
            accordance with the Contribution Agreement shall be booked into
            the capital account II of Behringwerke.

            4.3.1     49 % of such capital is transferred according to the
                      Purchase Agreement to the capital account II of 31.
                      Corsa GmbH.

            4.3.2     Any future contribution of Behringwerke to the
                      Partnership pursuant to the Contribution Agreement will
                      be booked at 51% into the capital account II of
                      Behringwerke and at 49% into the capital account II of
                      31. Corsa GmbH.

            4.3.3     The contributions to the capital accounts II are fixed
                      and may not be withdrawn by either Partner.

      4.4   Profits of the Partnership which are not distributed are booked
            into the reserve account of each Partner in proportion to their
            Partnership Interest.

      4.5   Losses attributable to each Partner shall be booked into the
            loss-carry-forward account of each Partner in proportion to their
            Partnership Interest.

<PAGE>
                                     4



      4.6   Distributable profit shares, withdrawals, compensation for
            services rendered, commissions, other than commissions pursuant
            to clause 4.7 of the Purchase Agreement, which shall be paid to
            Behringwerke in accordance with the Purchase Agreement,
            reimbursement of expenses, interest and all other payments
            between the Partnership and the Partners shall be booked into the
            respective transaction accounts.

      4.7   In addition, separate loan accounts shall be kept to the extent
            Partners grant loans to the Partnership.

      4.8   The capital accounts I and II, the reserve accounts and the
            transaction account shall not bear interest.  Debit and credit 
            balances of loan accounts, if any, shall bear interest at the rate 
            specified in the relevant loan agreement, if any, or at due year 
            FIBOR.


  5.  FISCAL YEAR, ANNUAL FINANCIAL STATEMENTS; INDEMNIFICATION

      5.1   The fiscal year runs from January 1 of each year to December 31.

      5.2   Within two months after the end of each fiscal year,the General
            Partner shall prepare the annual financial statements (annual
            balance sheet and profit and loss statements) for the preceding
            fiscal year and shall promptly submit and explain the annual
            financial statements to the Advisory Board members and to the
            appointed auditors for the purpose of examination.

      5.3   With respect to the structure (Gliederung) and evaluation
            (Bewertung), the financial statements shall comply with such
            applicable for corporations (Kapitalgesellschaften) pursuant to
            German generally accepted accounting principles ("GAAP"), a
            supplement (Anhang) and situation report (Lagebericht) are not
            necessary.  As a matter of principle, the financial statements
            must comply with the applicable provisions of profit
            determination pursuant to German Income Tax Law
            (einkommensteuerliche Gewinnermittlung), unless compulsory
            commercial law provisions, this Partnership Agreement, or
            partnership resolutions provide otherwise.

            To the extent that assessments by the tax authorities require a
            revision of the financial statements, only such revised financial
            statements shall govern rights

<PAGE>
                                     5



      5.4   To the extent that assessments by the tax authorities require a
            revision of the financial statements, only such revised financial
            statements shall govern rights and duties of the parties
            hereunder.  To the extent that such tax assessment requires a
            revision of the financial statements for several years, it is for
            internal purposes sufficient to amend the last financial
            statement.  The distribution of profits pursuant to clause 6.2
            shall be adapted for all financial statements subject to such
            revision.

      5.5   The financial statements shall be audited.  Auditor may only be
            an internationally recognized Wirtschaftsprufungsgesellschaft
            acceptable to all parties hereof.

      5.6   Upon approval of the financial statements by the Advisory Board
            and the Partners' Meeting, they shall be signed by the
            Geschaftsfuhrer of the General Partner.

      5.7   The annual financial statements shall also be prepared in
            accordance with U.S. GAAP.


      5.8   Each Limited Partner may also, without approval of the General
            Partner, exercise  information rights and controlling rights
            pursuant to sects. 118, 166 Commercial Law (HGB) whereby
            each Limited Partner can exercise such rights through a third
            person who  is bound by a professional confidentiality
            obligation.


  6.  Distribution of Profits and Losses

      6.1   The Partners shall share in the profits and losses as calculated
            after deduction of the expenses of the General Partner and of any
            compensation otherwise due to the Partners in the ratio of their
            Partnership Interests.  Regardless of the consummation of any
            transfer of the 51% Partnership Interest from Behringwerke AG to
            31.  Corsa GmbH pursuant to the Purchase Agreement (i.e.,
            exercise of Chiron Call Option or Behring Put Option), 31. Corsa
            GmbH shall at any time indemnify Behringwerke AG for any tax
            obligations relating to tax periods after the Closing Date of
            Behringwerke AG stemming from its Partnership Interest unless
            covered by clause 6.2; the indemnification

<PAGE>

                                     6





            is limited to tax claims relating to trade tax and value added
            tax but shall in no way include capital gain tax.

      6.2   Profit shares necessary to balance withdrawals of Partners for
            tax payments shall be booked on the transaction account.  The
            remainder of the profits shall be booked into the reserve
            accounts or the loss carry forward accounts as appropriate,
            unless the Partners unanimously provide otherwise.

      6.3   As long as a loss carry forward exists in the loss carry forward
            accounts, it shall be compensated by subsequent profits.  Only
            thereafter may any profit shares be booked into the transaction
            account or the reserve accounts.


  7.  WITHDRAWALS

      7.1   Each Partner may request withdrawals only from credit balances on
            its transaction account.

      7.2   Any withdrawals in excess thereof shall require a resolution by
            the Partners.


  8.  MANAGEMENT, REPRESENTATION

      8.1   The General Partner shall solely be entitled and shall have the
            sole responsibility to manage and represent the Partnership.

            The General Partner shall obtain the Advisory Board's approval
            for all business decisions which are of material importance to
            the Partnership, including, but not limited to, approval of the
            annual budget and the following matters:

            8.1.1     sale or acquisition of a company, parts of a company,
                      business (Betriebe) or parts of a business
                      (Betriebsteile) or entering into, or termination of
                      company lease agreements (Betriebspachtvertrage):

            8.1.2     sale, acquisition or encumbrance of controlling
                      interests in any other company or business:

<PAGE>
                                     7




            8.1.3     taking up new area of business and activities or
                      cessation of existing areas of business and activities;

            8.1.4     entering into, amendment and termination of enterprise
                      contracts (Unternehmensvertrage);

            8.1.5     acquisition, sale and transfer, encumbrance and pledge
                      of fixed assets, including real property, buildings and
                      rights of real property nature (if the transaction
                      value in each individual case is in excess of DM
                      500,000 (in words: Deutsche Mark five hundred
                      thousand);

            8.1.6     entering into or amending any contract with a value of
                      more than DM 500,000 (in words: Deutsche Mark five
                      hundred thousand);

            8.1.7     taking up and granting of loans and credits,
                      assumptions of guarantees, strict guarantees and other
                      liabilities of similar nature if the transaction value
                      in each case is in excess of DM 500,000 (in words:
                      Deutsche Mark five hundred thousand);

      8.2   The approval of the Advisory Board to be obtained pursuant to the
            foregoing may also be made in form of a general authorization for
            particular types of the aforementioned transactions and matters.
            Any such general authorization must precisely describe the
            transactions and matters in question as well as the purpose and
            the time frame in which they must be completed.


  9.  ADVISORY BOARD

      9.1   The Partnership shall have an Advisory Board.  The Advisory Board
            shall be composed of four (4) members.  Each Limited Partner
            shall appoint two members (including one senior member).

      9.2   The Advisory Board shall advise the management and shall consider
            for approval the consents required according to clause 8.

<PAGE>

                                    8

      9.3   The Advisory Board shall resolve its decision with a simple
            majority of its votes.  In the event that a majority decision
            cannot be reached, the following special procedures shall be used
            to break a deadlock:

            9.3.1     the senior Advisory Board member appointed by 
                      Behringwerke, following reasonable consultation with the 
                      senior member appointed by the other party, shall have 
                      the decisive vote in matters relating to the following 
                      agreements:

            [CONFIDENTIAL TREATMENT REQUESTED]

            9.3.2     The senior Advisory Board member appointed by Chiron, 
                      following reasonable consultation with the senior member 
                      appointed by the other party, shall have the decisive 
                      vote in all other matters referred to the Advisory Board.

      9.4   The Advisory Board shall meet at least every 14 months or whenever 
            requested by the CEO or by any of the senior members of the Advisory
            Board.  The meetings can be held by telephone or video conference.
            Meetings shall convene with a notice period of seven (7) days if 
            not otherwise unanimously agreed.  Action can be taken by unanimous 
            written consent.  The Advisory

<PAGE>
                                      9



            Board may adopt its own internal rules of procedure to be adapted 
            from time to time.


  10. Partners' Resolutions, Partners' Meeting

      10.1  The decisions reserved to the Partners by law or by the
            Partnership Agreement regarding the affairs of the Partnership
            shall be made by resolutions of the Partners.

      10.2  Partners' resolutions shall be adopted in partners' meetings
            unless the General Partner requests that a resolution is adopted
            in writing, by telex, by telefax and no objection is raised by a
            Limited Partner.

      10.3  The partners' meeting shall be called by the General Partner in
            its own right or upon request of any Limited Partner.  The
            General Partner may join the partners' meetings unless the
            partners request otherwise.

      10.4  The partners' meeting shall have a quorum when at least 75% of
            the Limited Partnership Interest is represented.  If a properly
            convened meeting has no quorum within one (1) hour of the time
            for which it was convened, the meeting shall automatically be
            adjourned and reconvened for the same time at the same place five
            business days later.  Such reconvened meeting shall have a quorum
            if at least one Limited Partner is present.  All resolutions of
            the partners' meeting require a simple majority of the votes
            present or represented at the meeting unless a higher majority is
            required by law.

      10.5  Each DM 1,000 of the Limited Partnership is equivalent to one
            vote.

      10.6  Except as otherwise provided in this Partnership Agreement, the
            Partners may also vote in matters of their own.

      10.7  Resolutions of the Partners shall be recorded in the minutes of
            the Partners' meeting or, in case of resolutions adopted outside
            of such meetings, in separate minutes to be drawn up and to be
            signed by the General Partner.The
            Partners shall in each case receive copies of such minutes  without
            delay.
                                    10

      10.8  Partners may only challenge the validity of Partners' resolutions
            within a period of one month following adoption in a Partners'
            meeting in which they have participated, or following receipt of
            the minutes recording the Partners' resolution by filing suit.
            After expiration of the above period, any defect of a Partners'
            resolution shall be deemed cured.


  11. TRANSFER OF PARTNERSHIP INTERESTS

      The Partners agree that any transfer, assignment or encumbrance of the
      Partnership Interest or parts thereof requires the prior written
      consent of the other Partner, which shall not be unreasonably withheld,
      provide that, (i) no consent shall be required if the Limited
      Partnership interests are transferred, assigned or encumbered to, or
      for the benefit of, a wholly owned subsidiary of the respective Partner
      and which will remain such a wholly owned subsidiary of a Partner, and
      (ii) such Partner has proven to the other Partner by submission of a
      written agreement that such subsidiary has agreed to be bound by be
      terms of this Agreement and the Purchase Agreement.  For the avoidance
      of doubt: no such transfer or assignment by 31. Corsa GmbH may in any
      respect impair Behringwerke AG's rights under the Purchase Agreement in
      particular, its rights against the Guarantor for payment of the Option
      Purchase Price in case the Chiron Call Option or the Behring Put Option
      is exercised.

  12. Bankruptcy

      In the event a bankruptcy or judicial composition proceeding is opened
      with respect to the assets of a Partner, the membership of such Partner
      shall terminate as soon as the underlying court order becomes final.


  13. TERM OF THE PARTNERSHIP

      13.1  The partnership shall commence upon its being established.

<PAGE>

                                     11


      13.2  The partnership is established for an indefinite period of time;
            the partnership may be terminated for the first time with a
            written notice of 6 months to December 31, 2001.

            If any of the Partners ceases to be a member of the partnership
            and his Partnership Interest is not transferred to a successor,
            the other Partner may take over the Partnership Interest in whole
            or in part.

      13.3  In case of dissolution of the partnership, the liquidation shall
            be effected in accordance with the statutory rules by
            liquidators.  Each Limited Partner participates in the
            liquidation surplus in the ratio of his Limited Partnership
            Interest.

      13.4  Effective as of January 1, 2002, this Partnership Agreement shall
            be adjusted to reflect the German Commercial Code (HGB).

  14. WITHDRAWAL COMPENSATION

      In the event a Partner withdraws from the partnership or the
      membership of this Partner is terminated due to Sect. 12, such Partner
      shall receive a withdrawal compensation . The withdrawal compensation
      shall be the nominal amount of the Partnership Interest of the
      withdrawing partner plus the balance in his transaction account.  The
      withdrawal compensation is payable in equal installments over a period
      of five years.

  15. Compensation of General Partner

      15.1  To the extent the General Partner's business activities are
            exclusively activities in connection with or on behalf of the
            Partnership, the Partnership shall reimburse the General Partner
            for all expenses incurred therewith.


      15.2  In addition to clause 15. 1, the General Partner shall receive at
            the end of each fiscal year of the Partnership a compensation in
            the amount of 2 % of the General Partner's net equity value as of
            the beginning of such financial year.

      15.3  Any compensation paid to the General Partner shall be booked as
            cost in the profit and loss statements of the Partnership.

<PAGE>

                                    12


  16. CAPITAL INJECTION; SHAREHOLDER LOANS

      16.1  Under no circumstances Behringwerke AG is obliged to inject any
            capital into the partnership or to grant any shareholder loans.

      16.2  31. Corsa GmbH undertakes the responsibility to ensure that the
            Partnership shall have sufficient cash to meet all its
            obligations for at least a period of 6 (six) months after the
            Closing Date as defined in the Purchase Agreement.

  17. CONCLUDING PROVISIONS

      17.1  The Partners shall keep all confidential information received
            from the partnership or from the other Partners in strict
            confidence without limitation in time, even after their
            withdrawal from the partnership.

      17.2  In case individual provisions of the Partnership Agreement are or
            become invalid in whole or in part, the validity of the remaining
            provisions shall remain unaffected thereby.  The parties shall
            instead of the invalid provision agree on an appropriate valid
            provision which approximates best the intent and purpose of the
            invalid provision.

      17.3  This Partnership Agreement and its interpretation shall be
            governed by the laws of the Federal Republic of Germany.  Court
            venue shall be Marburg for all disputes among the Partners.

      17.4  31. Corsa GmbH shall hold Behringwerke free and harmless from any
            damages and shall actually conduct all relevant negotiations and
            court proceedings on behalf of Behringwerke, as a consequence of
            any withdrawals from the capital account I caused or otherwise
            initiated by 31. Corsa GmbH, including withdrawals after exercise
            of the Chiron Call Option or the Behring Put Option and shall
            hold Behringwerke free and harmless; this also applies in case of
            withdrawals necessary for the satisfaction of clause 4.7 of the
            Purchase Agreement.


<PAGE>

                                                                     ANNEX 3.4
                                                      to the Purchase Agreement



                               SHAREHOLDERS' AGREEMENT
                          For VuCo GmbH and VuCo GmbH & Co.
                          ---------------------------------



BETWEEN

Behringwerke AG
                                                               ("Behringwerke")


AND



         31. CORSA Verwaltungsgesellschaft mbH
                                                                      ("Buyer")



         (Behringwerke and the Buyer each also referred to as "Shareholder" or
         "Party")


<PAGE>

                                          2



INTRODUCTION

A.  Pursuant to the purchase and assignment agreement, of which this Agreement
    forms an annex (the "Purchase Agreement"), Behringwerke has sold to Buyer a
    49% interest in VuCo GmbH and VuCo GmbH & Co. (hereinafter collectively the
    "Companies").

B.  With regard to the exercise of Behringwerke's and the Buyer's rights as
    shareholders and partners of the Companies, the Parties wish to enter into
    this Shareholders' Agreement in order to coordinate their cooperation with
    regard to the management of the Companies.

C.  All terms defined in the Purchase Agreement shall have the same meaning in
    this Shareholders' Agreement.

In consideration hereof the parties agree as follows:

1.  STRUCTURE OF THE COMPANIES

    1.1  VuCo GmbH & Co. is organized as a limited partnership with VuCo GmbH
         as its sole general partner. VuCo GmbH & Co. will be exclusively
         managed and represented by VuCo GmbH.

    1.2  VuCo GmbH will be managed by a Chief Executive Officer
         (GESCHAFTSFUHRER).  The Chief Executive Officer shall not be bound by
         fiduciary obligations vis-a-vis any particular Shareholder other than
         those applicable vis-a-vis all Shareholders pursuant to law, the
         Articles of Association of VuCo GmbH (the "Articles"), the Partnership
         Agreement of VuCo GmbH & Co. (the "Partnership Agreement") and this
         Shareholders' Agreement.

    1.3  VuCo GmbH & Co. shall have an Advisory Board (BEIRAT).

    1.4  To the extent the Companies will be required to establish an
         AUFSICHTSRAT by matter of law, the parties hereto will pursue the
         intent of this Agreement regardless of such AUFSICHTSRAT.


<PAGE>

                                          3



2.  RULES GOVERNING THE SHAREHOLDERS' MEETINGS AND PARTNERS' MEETINGS

    2.1  The shareholders' meetings of VuCo GmbH shall be convened at regular
         intervals not exceeding 14 months and upon no less than seven (7)
         business days notice in writing, such notice to include an agenda
         specifying the matters to be resolved.

    2.2  The shareholders' meetings of VuCo GmbH shall be called in by the
         Chief Executive Officer of VuCo GmbH in its own right or upon request
         of any Shareholder.  The Chief Executive Officer may join the
         shareholders' meetings, unless any Shareholder requests otherwise.

    2.3  The shareholders' meeting shall have a quorum when at least 75 % of
         the stated capital of VuCo GmbH are represented.  If a properly
         convened meeting has no quorum within 1 (one) hour of the time for
         which it was convened, the meeting shall automatically be adjourned
         and reconvened for the same time at the same place five business days
         later.  Such reconvened meeting shall have a quorum if at least one
         Shareholder is present.  All resolutions of the shareholders' meeting
         require a simple majority of the votes, present or represented at the
         meeting, unless a higher majority is required by law.

    2.4  For the partners' meetings of VuCo GmbH & Co., the foregoing
         provisions shall apply MUTATIS MUTANDIS.


3.  PRINCIPLES OF MANAGEMENT

    3.1  The management of VuCo GmbH shall obtain the Advisory Board's approval
         for all business decisions which are of material importance to VuCo
         GmbH or VuCo GmbH & Co., including, but not limited to, approval of
         the annual budget and plan, and the following matters:

         (a)  sale or acquisition of a company, parts of a company, business
              (BETRIEBE) or parts of a business (BETRIEBSTEILE) or entering
              into, or termination of company lease agreements
              (BETRIEBSPACHTVERTRAGE);


<PAGE>

                                          4



         (b)  sale, acquisition or encumbrance of controlling interests in any
              other company or business;

         (c)  taking up new area of business and activities or cessation of
              existing areas of business and activities;

         (d)  entering into, amendment and termination of enterprise contracts
              (UNTERNEHMENSVERTRAGE);

         (e)  acquisition, sale and transfer, encumbrance and pledge of fixed
              assets, including real property, buildings and rights of a real
              property nature, if the transaction value in each individual case
              is in EXCESS of DM 500,000 (in words: Deutsche Mark five hundred
              thousand);

         (f)  entering into or amending any contract with a value of more than
              DM 500,000 (in words: Deutsche Mark five hundred thousand);

         (g)  taking up and granting of loans and credits, assumption of
              guarantees, strict guarantees and other liabilities of the
              similar nature if the transaction value in each case is in excess
              of DM 500,000 (in words: Deutsche Mark five hundred thousand);

         (h)  any of the transactions and matters listed and referred to under
              sub-para. (a) through (g) above carried out by VuCo in its
              capacity as general partner of VuCo GmbH & Co. for and on behalf
              of VuCo GmbH & Co.

3.2 The approval of the Advisory Board to be obtained pursuant to para. 3.1
    above may also be made in form of a general authorization for particular
    types of the aforementioned transactions and matters.  Any such general
    authorization must precisely describe the transactions and matters in
    question as well as the purpose and the time frame in which they must be
    completed.


<PAGE>

                                          5



4.  ADVISORY BOARD

    4.1  The Advisory Board shall be composed of 4 (four) members. Each Party
         shall appoint two members (including one senior member).

    4.2  The Advisory Board shall advise the management and shall consider for
         approval the consents required according to Sect. 3.1. The Chief
         Executive Officer of VuCo GmbH shall be nominated by the Advisory
         Board to the Shareholders for appointment.  The Advisory Board shall
         negotiate and determine the employment contract with the Chief
         Executive Officer.

    4.3  The Advisory Board shall resolve its decisions with a simple majority
         of its votes, In the event that a majority decision cannot be reached,
         the following special procedures shall be used to break the deadlock:

         (a)  the Senior Advisory Board Member appointed by Behringwerke,
              following reasonable consultation with the Senior Member
              appointed by the other party. shall have the decisive vote in
              matters relating to the following agreements:

              [CONFIDENTIAL TREATMENT REQUESTED]


<PAGE>

                                          6



         (b)  the Senior Advisory Board Member appointed by Buyer, following
              reasonable consultation with the Senior Member appointed by the
              other party, shall have the decisive vote in all other matters.

    4.   The Advisory Board shall meet at least every 14 months or whenever
         requested by the Chief Executive Officer or by any of the senior
         members of the Advisory Board.  The meetings can be held by telephone
         or video conference.  Meetings shall convene with a notice period of 7
         (seven) days if not otherwise unanimously agreed.  Action can be taken
         by unanimous written consent.  The Advisory Board may adopt its own
         internal rules of procedure to be adapted from time to time.

5.  EXERCISE OF VOTING RIGHTS

    5.1  Shareholders' resolutions or partners' resolutions in shareholders'
         meetings, as the case may be, regarding the following matters shall
         require a unanimous vote of the shareholders or the partners:

         (a)  matters concerning capital increases and capital decreases.

         (b)  appointment of the Chief Executive Officer.

         (c)  appointment of the Companies' auditors, determination
              (FESTSTELLUNG) of the annual financial statements and profit
              distributions including distributions of reserves (RUCKLAGEN):

         (d)  exoneration (ENTLASTUNG) of the managing directors.

         (e)  amendments of the Articles or the Partnership Agreement to the
              extent that such amendments relate to, or have an impact on, any
              of the matters stipulated, mentioned or referred to in this
              Shareholders' Agreement:

         (f)  transformation (UMWANDLUNG) of the Companies as defined in Sec. 1
              Umwandlungsgesetz or dissolution of the Companies:


<PAGE>

                                          7



         (g)  entering into, amendment and termination of enterprise contracts
              (UNTERNEHMENSVERTRAGE);

         (h)  transfer of any decision powers of shareholders' meeting of VuCo
              GmbH or the partners"meeting of VuCo GmbH & Co. to any
              committees;

         (i)  the sale or acquisition of assets having a value in excess of DM
              50 million;

         (j)  debt financing in excess of DM 50 million, other than financing
              of accounts receivable;

         (k)  matters relating to the Overview Agreement after the consent and
              approval contemplated by section 5.1.4 of the Purchase Agreement
              has been obtained;

         (1)  matters relating to the Sales Promotion and Consignment Agreement
              between Behringwerke and Centeon Pharma dated September 28, 1995
              and effective as of July 1, 1995.

    5.2  If Behringwerke and Buyer are unable in two consecutive shareholders'
         meetings or partners' meetings, as the case may be, to reach an
         unanimous decision on matters requiring their unanimous vote and if
         they have not been able to resolve the matter within 30 days after the
         date of the second shareholders' meeting or partners' meeting, then
         Behringwerke and the Buyer can submit this matter to the respective
         member of the management board (VORSTAND) of Hoechst AG in charge of
         the business activities conducted by Behringwerke and of Guarantor for
         resolution.  They shall meet as necessary in order to discuss and
         resolve the matter by mutual agreement considering, if feasible, the
         use of expert advisors.

    5.3  With regard to matters other than those listed and referred to in
         para. 4.3.a and 5.1 above, Behringwerke shall exercise its voting
         rights in shareholders' meeting of VuCo GmbH and partners' meetings of
         VuCo GmbH & Co. consistent with the manner in which the Buyer
         exercises its voting rights it being under-


<PAGE>

                                          8



         stood that with regard to the matters listed and referred to in para
         5.1 above, Behringwerke may exercise its voting rights at its free
         discretion.

6.  TRANSFER, ASSIGNMENT OR ENCUMBRANCE OF SHARES OR INTERESTS

    The Parties agree that any transfer, assignment or encumbrances of shares
    or interests in VuCo GmbH or VuCo GmbH & Co. or parts thereof requires the
    prior written consent of the other shareholder or partner not to be
    unreasonably withheld, PROVIDED THAT no consent shall be required if (i)
    the shares or interests are transferred, assigned or encumbered to, or for
    the benefit of a wholly-owned subsidiary of the respective
    shareholder/partner and (ii) such shareholder/partner has proven to the
    other shareholder/partner by submission of a written agreement that such
    subsidiary has agreed to be bound by the terms of this Agreement pursuant
    to Sect. 11.

7.  AMENDMENTS OF ARTICLES OF ASSOCIATION AND PARTNERSHIP AGREEMENT

    Insofar as amendments of the Articles and the Partnership Agreement or any
    other resolutions are necessary or expedient for the execution and
    implementation of the provisions of this Shareholders' Agreement,
    Behringwerke and the Buyer shall procure that the appropriate resolutions
    are passed and all other necessary actions are taken promptly after the
    Closing Date.


8.  Financials; Information

    8.1  The financial statements of VuCo GmbH and VuCo GmbH & Co. shall be
         audited by an auditor (WIRTSCHAFTSPRUFER) nominated by the
         shareholders' meeting.

    8.2. Each Shareholder shall have the right to inspect (either itself or by
         advisors subject to a professional obligation of secrecy) during
         normal business hours (and at other times by agreement) all books,
         records and other information maintained for or by the Companies and
         (to the extent legally permissible) those maintained for or by its
         associated undertakings.  The right to inspect shall include the right
         to take copies.  Each Shareholder shall also have the right of


<PAGE>

                                          9



         access to the Companies' premises (either itself or by advisors
         subject to a professional obligation of secrecy) during normal
         business hours (and otherwise by agreement) for the above purpose and
         to inspect and review the premises.

9.  Duration

    This Agreement shall take effect as of the Closing Date and shall expire

    (a)  as of the date of notarization of the acceptance of the Behring Put
         Option or the Chiron Call Option, as the case may be, pursuant to Art.
         3 of the Purchase Agreement, or

    (b)  as of the date at which the right of Behringwerke to exercise the
         Behringwerke Put Option and the right of the Buyer to exercise the
         Chiron Call Option pursuant to Art. 3 of the Purchase Agreement has
         expired, or

    (c)  at such other date on which the Parties have mutually agreed.

10. NO PARTNERSHIP

    None of the provisions of this Agreement shall be deemed to constitute a
    partnership between the Shareholders and neither of them shall have any
    authority to bind the other in any way.

11. SUCCESSORS AND ASSIGNMENTS

    This Agreement shall enure for the benefit of and be binding on the
    respective successors in title and permitted assignees of each Shareholder
    which shall procure prior to the transfer of any of its Shares that each
    such transferee shall enter into a written agreement with the other
    Shareholders by which the transferee agrees to be bound by terms identical,
    mutatis mutandis, to the terms of this Agreement (including the terms of
    this clause as regards any subsequent transfer of the Shares).


<PAGE>


                                                            Annex 4.6 to the
                                                            Purchase Agreement





                          [CONFIDENTIAL TREATMENT REQUESTED]

                                     (1 Page)






<PAGE>

                                                              Annex 4.7 to the
                                      to the Purchase and Assignment Agreement

                       TERMS AND CONDITIONS FOR COMMISSION




1.  Under Art. 4.7 of the Purchase and Assignment Agreement, Buyer agrees to 
    pay Behringwerke, in addition to the Fixed Cash Purchase Price and the 
    Option Purchase Price, a yearly Commission on the sales of Guarantor's 
    and its affiliates' vaccine products listed on ANNEX 1 hereto for use in 
    Germany during the years 1997 through 2001, calculated as [CONFIDENTIAL
    TREATMENT REQUESTED] of the excess of net sales over the following 
    forecast:


    -     1997:    DM [CONFIDENTIAL TREATMENT REQUESTED]

    -     1998:    DM [CONFIDENTIAL TREATMENT REQUESTED]

    -     1999:    DM [CONFIDENTIAL TREATMENT REQUESTED]

    -     2000:    DM [CONFIDENTIAL TREATMENT REQUESTED]

    -     2001:    DM [CONFIDENTIAL TREATMENT REQUESTED]


    Such figures shall be adjusted for actual inflation on the basis of a 
    consumer price index (four-person-households average income) from 
    Closing Date to December 31 of each of the above-mentioned years.


2.  Buyer shall submit to Behringwerke by March 31 of the years 1997 through 
    2002 an auditable calculation and documentation of the total sales of 
    Buyer's vaccine products in Germany.


3.  The Commission shall be due and payable on March 31 of each respective 
    year.  Payment shall be made in Deutsche Mark by wire transfer free of 
    cost to the account of Behringwerke listed in clause 4.4 of the Purchase
    and Assignment Agreement in time to be received on the respective due 
    date.  Late payments shall bear interest at discount rate plus three 
    basis points.


4.  Behringwerke's experts (as designated by Behringwerke and reasonably 
    acceptable to Buyer) shall be entitled to audit, together with the 
    respective department of

<PAGE>

                                       2




    Buyer, any such calculations presented by Buyer, shall have reasonable 
    access to the business sites of Behring Vakzine GmbH & Co. or any 
    successor and to all books, records and other documents relating to such 
    calculation, and shall obtain from Buyer all information reasonably 
    requested.  The persons performing such audit on Behringwerke's behalf 
    shall treat confidential any information that they had access to, shall 
    use such information solely for the purpose of confirming the amounts due 
    hereunder, and shall report to Behringwerke's management exclusively.


5.  To the extent an audit pursuant to clause 3 above reveals any differences 
    from the calculation presented by Buyer, the balance shall be settled in 
    accordance with clause 3 within four weeks after the parties agreed on 
    such difference.


6.  As used herein, "net sales" means the amount invoiced for sales to 
    unaffiliated third parties of Guarantor, less (i) discounts, rebates, 
    chargebacks and allowances, (ii) returns, credits, recalls and 
    withdrawals, (iii) freight, insurance and packaging, (iv) V.A.T. and 
    other excise taxes, duties and other governmental charges, all to the 
    extent any of these are applicable to such sales.


<PAGE>





                                                                      Annex 1 of
                                             Annex 4.7 of the Purchase Agreement





                          [CONFIDENTIAL TREATMENT REQUESTED]

                                    (1 page)


<PAGE>



                                                                   Annex 7.1.16
                                                       to the Purchase Agreement






                          [CONFIDENTIAL TREATMENT REQUESTED]

                                    (1 page)


<PAGE>


                                                                  Annex 7.1.18
                                                         to Purchase Agreement





                          [CONFIDENTIAL TREATMENT REQUESTED]

                                    (1 page)


<PAGE>


                                                                 Annex 7.1.19
                                                    to the Purchase Agreement






                          [CONFIDENTIAL TREATMENT REQUESTED]

                                    (2 pages)

<PAGE>

                                                                  ANNEX  8



                                                      to Purchase Agreement





Use of name:

- -  Chiron Behring Biocine GmbH

- -  Chiron Behring Biocine GmbH & Co. KG


Use of logo:


BEHRING


<PAGE>

                                                                     ANNEX  11



                                                         to Purchase Agreement





                              HOECHST AKTIENGESELLSCHAFT
                                           



Chiron Corporation 
4560 Horton Street
Emeryville, CA   94608-2916

USA                                                           February 6, 1996



Ladies and Gentlemen:

Referring to the Purchase and Assignment Agreement to be entered between Chiron
GmbH and Behringwerke Aktiengesellschaft relating to the human vaccine business
of Behringwerke Aktiengesellschaft we confirm the following:

1.  For a period of five (5) years from the Closing Date of the aforementioned
    Purchase and Assignment Agreement (the "Protected Period") Hoechst and
    affiliated companies within the meaning of Section 18 of the German Stock
    Corporation Law (Aktiengesetz) will refrain from developing, marketing,
    producing, selling or otherwise distributing human prophylactic vaccines
    against infectious diseases.

2.  This obligation of non-competition shall be applicable worldwide, but for
    the following:

    Hoechst Ag owns a [Confidential Treatment Requested].  In addition, certain
    Hoechst AG affiliates manufacturer and sell human vaccine products
    [Confidential Treatment Requested].  Hoechst commits that none of these
    aforementioned affiliates will [Confidential Treatment Requested].

3.  Hoechst AG shall continue with VuCo GmbH & Co. the existing arrangements
    between Behringwerke and Hoechst AG with respect to the distribution of
    human vaccine products outside Germany at arm's length terms to be agreed
    upon, for not less than [Confidential Treatment Requested].

<PAGE>

                                                                      ANNEX 11

4.  In the event that, within 5 years from the Closing Date, VuCo proposes to
    have developed a human vaccine that is covered by an existing Hoechst AG
    patent, VuCo shall have the right to obtain a license under such patent for
    such product on commercially reasonable terms.

5.  Hoechst hereby consents to clause 3.5 of the Contribution Agreement as it
    relates to Hoechst patents.


Yours Sincerely,


HOECHST AKTIENGESELLSCHAFT


<PAGE>


                         [CONFIDENTIAL TREATMENT REQUESTED]

[Certain confidential information has been omitted from the Agreement and filed
separately with the Securities and Exchange Commission pursuant to a request by
Registrant for confidential treatment pursuant to Rule 24b-2.  The omitted
confidential information has been identified by the following statement:
"CONFIDENTIAL TREATMENT REQUESTED".]

                        CLOSING AGREEMENT

by and among

Behringwerke Aktiengesellschaft
D-30501 Marburg
represented by its members of the Management Board,
Prof Dr. Dr. Uwe Bicker and Dr. Bernd Neuefeind

(hereinafter "Behringwerke")

                                                          - on the one side -

and

Chiron Corporation

4560 Horton Street, Emeryville, CA 94608-2916, U.S.A.
represented by its Chairman of the Board,
Dr. William J. Rutter

(hereinafter "Chiron")

and

31. CORSA Verwaltungsgesellschaft mbH

represented by power of attorney by
Dr. Dino Dina,

(hereinafter "31.  CORSA")

                                                          - on the other side -


(Behringwerke, Chiron and 31. CORSA are hereinafter collectively referred to as
the "Parties" or, individually, as the "Party", as the context requires.)


<PAGE>

    PREAMBLE

A.  On February 17, 1996, the Parties entered into a Purchase and
    Assignment Agreement (Notarized Deed A. Prot. 1996/20 of the notary public
    Dr. Werner Wenger in Basle - hereinafter the "Purchase Agreement") with
    respect to the transfer 49% of the interests in a newly organized limited
    partnership which will continue to operate the human vaccine business of
    Behringwerke under the name Chiron Behring GmbH & Co (presently registered
    under the name Behring Vakzine GmbH & Co) and the transfer of a share in
    the nominal value of DM 24,500 in Chiron Behring Biocine GmbH
    Verwaltungsgesellschaft (which will be renamed into and referred to
    herein- after as "Chiron Behring GmbH") being the general partner of Chiron
    Behring GmbH & Co (hereinafter collectively the "Interests").

B.  Under the Purchase Agreement, the effectiveness of the transfer of
    the Interests requires the fulfillment of certain conditions.  The Parties
    now wish to clarify the status of and to modify such conditions.

C.  The Parties also wish to amicably settle certain issues which have come
    to their attention since the execution of the Purchase Agreement.

    NOW, THEREFORE, the Parties agree as follows:


    1.   FULFILLMENT OF CONDITION

         1.1   Behringwerke hereby declares that

              (i)  Chiron Behring GmbH & Co is holding all official
                   approvals for the operation of the Business (as defined in
                   the Purchase Agreement) as currently conducted pursuant to
                   the ARZNEIMITTELGESTZ, GENTECHNIKGESETZ, TIERSCHUTZGESETZ
                   and BUNDESSEUCHENGESETZ;


              (ii) the Operating Lease Agreement between Behringwerke
                   and Chiron Behring GmbH & Co will terminate with effect as
                   of the Closing Date (as defined hereinafter);

              (iii)the Contribution Date pursuant to the Contribution Agreement
                   (all as defined in the Purchase Agreement) has occurred on
                   April 1,  1996;

              (iv) Behring Vakzine GmbH (formerly the Institut fur
                   Produkttest und Verbrauchsforschung GmbH) is no longer a
                   general partner of Chiron Behring GmbH & Co and Chiron
                   Behring GmbH is now the sole general partner;


<PAGE>

              (vi) the management of Chiron Behring GmbH has agreed to
                   the split of one of the shares of Behringwerke in Chiron
                   Behring GmbH with a nominal value of DM 25,000 into two
                   shares with nominal values of DM 24,500 and DM 500,
                   respectively, and to the transfer of the DM 24,500 share to
                   31. CORSA.

         1.2  Chiron hereby declares that the necessary merger control
              approval for the implementation of the Purchase Agreement has
              been granted.

         1.3  Subject to the provisions of clause 6, the Parties
              mutually waive the condition stated in clause 5.1.4 of the
              Purchase Agreement, i.e., [CONFIDENTIAL TREATMENT REQUESTED]

              During the interim period until the assignment of [CONFIDENTIAL
              TREATMENT REQUESTED] is effected with or without amendments, 
              Behringwerke shall internally place Chiron Behring GmbH & Co as 
              it would be if such assignment had been effected as of the Closing
              Date (as defined hereinafter).


    2.   PAYMENT OF THE PURCHASE PRICE

         2.1  The Parties are in agreement that 31. CORSA shall pay the
              purchase price for the Interests in the amount as agreed in
              clause 4 of the Purchase Agreement (i.e., DM 171,813,430.40, of
              which DM 313,430.40 represents 49% of the rent under the
              Operating Lease Agreement) on July 1, 1996 to be received by,
              Behringwerke by 11:00 h on such date on the following bank
              account:

                        COMMERZBANK AG, FRANKFURT A.M.-HOCHST
                                ACCOUNT NO.: 251 57 57
                           BANK SORT CODE (BLZ): 500 400 00

              Behringwerke hereby warrants that Chiron Behring GmbH & Co has
              received prior to July 1, 1996 a rent under the Operating Lease
              Agreement (as defined in the Purchase Agreement) for the months
              of April through June in an amount of DM 639,653.88 (plus V.A.T.
              if applicable).  Behringwerke shall promptly deliver to 31 CORSA,
              with a copy to Chiron, written evidence (bank statement) of such
              receipt.

         2.2  Upon receipt of the purchase price, Behringwerke shall
              immediately deliver to 31 CORSA a receipt of the purchase price
              received.  Such receipt shall be forwarded first by telecopy and
              then by overnight courier to the attention of Ms. Jessica Hoover
              at Chiron, Emeryville.


<PAGE>

3.  CLOSING DATE

    Under the condition that Behringwerke has received the purchase price for
    the Interests as agreed in clause 2 above, the transfer of the Interests
    shall be effective as of July 1, 1996, 0:01 h (the "Closing Date").


4.  GUARANTEE

    In accordance with clause 14.3 of the Purchase Agreement Chiron agrees to
    the following:

    In the event that Chiron does not exercise the Chiron Call Option by March
    31, 1998, and if at that time or any time thereafter the long term credit
    rating of Chiron's senior debt securities falls below grade "A" of Standard
    & Poor's rating or Moody's comparable rating, Chiron will provide a letter
    of credit from a commercial bank, acceptable to Behringwerke, or other
    credit support fully satisfactory to Behringwerke, in an amount sufficient
    to satisfy 31. CORSA's obligation to pay the Option Purchase Price
    (assuming Behringwerke exercise the Behring Put Option in March 2001).

    The foregoing is deemed to satisfy in full Chiron's obligations under
    clause 14.3 of the Purchase Agreement.


                           [CONFIDENTIAL TREATMENT REQUESTED]


<PAGE>


                           [CONFIDENTIAL TREATMENT REQUESTED]


6.  PARTNERSHIP AGREEMENT

    The Parties are in agreement that promptly hereinafter and with effect as
    of the Closing Date, Behringwerke, 31. CORSA and Chiron Behring GmbH shall
    enter into the Partnership Agreement as agreed in the Purchase Agreement.
    The Parties shall promptly procure the necessary filings at the competent
    commercial register with respect to the registration of 31. CORSA as a new
    limited partner (Kommanditist) in Chiron Behring GmbH & Co.


7.  CASH MANAGEMENT

    Behringwerke hereby informs Chiron that Hoechst AG has agreed in the time
    being and until further notice (which will not be given prior to September
    30, 1996) to finance any negative cash flow of Chiron Behring GmbH & Co up
    to an aggregate outstanding amount of DM 20,000,000. at an interest rate of
    DM LIBOR plus 0. 125 % p.a. for credits with a mutually fixed term not
    exceeding six months, and an interest rate equivalent to the then
    applicable call money rate plus 0.125% p.a. for call money credits.
    Details will be agreed upon for each individual credit in compliance with
    the then applicable rules of "Konzeminterner Finanzausgleich" (Group
    internal Borrowing and Lending) and/or "Tagesgeld-Aufnahme und Anlage"
    (Group internal Call Money Arrangements) of Hoechst AG.  Chiron hereby
    unconditionally guarantees repayment of any such credit by Chiron Behring
    GmbH & Co when due.


8.  MISCELLANEOUS


    8.1  Unless otherwise expressly stated herein, all terms of the
         Purchase Agreement shall remain in force.

                           [CONFIDENTIAL TREATMENT REQUESTED]


<PAGE>


                           [CONFIDENTIAL TREATMENT REQUESTED]


<PAGE>

IN WITNESS HEREOF, the Parties have executed this Closing Agreement in triple
originals by their respective, duly authorized Board Members.



BEHRINGWERKE AKTIENGESELLSCHAFT

Date: June 29, 1996
By:



    /s/ Dr. Uwe Bicker
- -------------------------------------------------
    (Prof. Dr. Dr. Uwe Bicker)



    /s/ Bernd Neuefiend
- -------------------------------------------------
    (Dr. Bernd Neuefeind)


CHIRON CORPORATION

Date: June 29, 1996
By:



    /s/ Dr. William J. Rutter
- -------------------------------------------------
    (Dr. William J. Rutter)


31. CORSA VERWALTUNGSGESELLSCHAFT MBH

Date: June 29, 1996
By:

    /s/ Dr. Dino Dina
- -------------------------------------------------
    (Dr. Dino Dina)


<PAGE>

June 29, 1996



                          [CONFIDENTIAL TREATMENT REQUESTED]

[Certain confidential information has been omitted from the Agreement and filed
separately with the Securities and Exchange Commission pursuant to a request by
Registrant for confidential treatment pursuant to Rule 24b-2.  The omitted
confidential information has been identified by the following statement:
"CONFIDENTIAL TREATMENT REQUESTED".]



Behringwerke Aktiengesellschaft
D-30501 Marburg
Germany


Re: Closing Agreement dated June 29, 1996 between Chiron Corporation, 31 CORSA
    and Behringwerke AG


Gentlemen:

As set forth in clause 1.3 of the Closing Agreement, Chiron Corporation and 31
CORSA have agreed to waive the condition stated in clause 5.1.4 of the Purchase
Agreement.  Such waiver is conditioned upon the following agreement:


(a) Subject to paragraph (b) below, in the event that [CONFIDENTIAL TREATMENT
    REQUESTED] Behringwerke shall fully indemnify Chiron Behring GmbH & Co for 
    any damage suffered.  This damage shall be calculated on the basis of the 
    time period of [CONFIDENTIAL TREATMENT REQUESTED]

(b) The obligation of Behringwerke to indemnify Chiron Behring GmbH & Co under
    paragraph (a) is limited to an amount equal to [CONFIDENTIAL TREATMENT
    REQUESTED]

(c) In the event that the [CONFIDENTIAL TREATMENT REQUESTED] are not assigned to
    Chiron Behring GmbH & Co by November 30, 1996 each party shall be entitled
    to rescind the Closing, in which case Behringwerke shall pay back to 31.
    CORSA any purchase price paid plus an interest of 5.125% p.a. and 31. CORSA
    shall retransfer to Behringwerke the Interests.  Any additional damages by
    either party is excluded, other than for damages incurred as a result of a
    breach by either party of their obligation under clause d.



<PAGE>

June 29, 1996

Behringwerke Aktiengesellschaft




(d) Subject to the foregoing, the Parties will use their best efforts to ensure
    that the assignment [CONFIDENTIAL TREATMENT REQUESTED] occurs as soon as 
    possible and  [CONFIDENTIAL TREATMENT REQUESTED].


If the foregoing accurately reflects your understanding of our agreement, please
sign a copy of this letter for our records.

Very truly yours,


CHIRON CORPORATION

By:      /s/ William J. Rutter
       --------------------------
         William J. Rutter
         Chairman


31. CORSA Verwaltungsgesellschaft mbH

By:      /s/ Dino Dina
       --------------------------
       Dino Dina, pursuant to a power of attorney


Agreed and Accepted:


BEHRINGWERKE AKTIENGESELLSCHAFT

By:      /s/ Dr. Dr. Uwe Bicker
       --------------------------
       Prof. Dr. Dr. Uwe Bicker

By:      /s/ Dr. Bernd Neuefeind
       --------------------------
       Dr. Bernd Neuefeind



<PAGE>

                                                                  Exhibit 10.87


                          [CONFIDENTIAL TREATMENT REQUESTED]

[Certain confidential information has been omitted from the Agreement and filed
separately with the Securities and Exchange Commission pursuant to a request by
Registrant for confidential treatment pursuant to Rule 24b-2.  The omitted
confidential information has been identified by the following statement:
"CONFIDENTIAL TREATMENT REQUESTED".]


                              ROYALTY PROJECTS AGREEMENT


This Agreement is entered into as of January 4, 1995 by and between CIBA CORNING
DIAGNOSTICS CORP., a Delaware corporation having its principal place of business
at 63 North Street, Medfield, MA 02052 U.S.A. (hereinafter "CCD"), and CIBA-
GEIGY Limited, a Swiss corporation having its principal place of business at
Klybeckstrasse 141, CH-4002 Basel, Switzerland (hereinafter Ciba).

WHEREAS, Ciba's Corporate Research Units ("CRU") conduct research projects
determined to have strategic benefit to Ciba;

WHEREAS, CCD wishes to evaluate such projects in order to identify whether they
have strategic potential for its own business in Diagnostics (as such term is
defined in Article 1.3 of this Agreement) and to obtain rights to exploit
results of such projects against compensation to Ciba in the form of royalties
and/or fees;

WHEREAS, Ciba is willing to make available results of certain projects for
exploitation in the field of Diagnostics by CCD against compensation in the form
of royalties and/or fees, under certain general conditions and project-specific
agreements, such projects being referred to herein as "Royalty Projects";

NOW, THEREFORE, in consideration of the premises and covenants, terms and
conditions set forth herein, Ciba and CCD agree as follows:

1.  SCOPE OF THE AGREEMENT; DEFINITIONS

    1.1  This Agreement governs the general procedures and terms to be applied
         for Royalty Projects to be conducted by CRU for use by CCD in 
         Diagnostics upon mutual agreement by the two parties from time to time.

    1.2  Projects started prior to January 4, 1995 and agreed by the parties
         during the Steering Committee Meeting of April 27, 1995 to be continued
         shall be considered Royalty Projects.  These projects and their 
         agreed-upon specific terms are described in Attachments A and B to this


<PAGE>

         Agreement.  Costs incurred by Ciba for such Royalty Projects prior to
         January 4, 1995 shall be considered as having been remunerated by the
         acquisition of CCD by Chiron Corporation.

    1.3  As used in this Agreement

         (a)  "Affiliate(s)" shall mean a corporation or any other business
              entity, in whatever country organized, which, directly or
              indirectly, controls, is controlled by or is under common control
              with Ciba or CCD, as the case may be.  For this purpose, control
              shall mean the ownership of 50% or more of the issued share
              capital or the legal power to direct or cause the direction of the
              general management and policies of the party in question.  In the
              case of CCD, "Affiliates" shall also include Ciba Corning
              Diagnostics de Mexico S.A., so long as CCD continues to own at
              least 49% of the voting stock of that corporation.

         (b)  "CCD License Option" shall have the meaning specified in Article
              4.4 hereof.

         (c)  "Designated Country" means Germany, France, Italy, the United
              Kingdom of Great Britain and Northern Ireland, Japan or the
              United States of America.

         (d)  "Diagnostics" shall mean the development, manufacture, use and
              sale of processes, materials, supplies and equipment for the
              diagnosis of human and veterinary health.

         (e)  "License Maintenance Fee" means the fee payable by CCD in
              accordance with Article 5.6.

         (f)  "Licensed Patents" means any and all letters patent, by whatever
              country issued, now or hereafter issued to Ciba and licensed to
              CCD in accordance with the provisions of this Agreement.


                                          2

<PAGE>

         (g)  "Net Sales" shall mean the gross sales of Royalty Products by 
               CCD, its Affiliates or sublicensees to third parties, less 
               trade, cash or volume discounts, returns and allowances, 
               charges for freight handling and transportation, sales and use 
               taxes and other similar taxes incurred, and royalties payable 
               by CCD or such Affiliate or sublicensee to third parties with 
               respect to such products, as determined in accordance with 
               CCD's standard accounting methods and recognized accounting 
               principles.  Where a Royalty Product is sold in combination 
               with a product which is not a Royalty Product, Net Sales shall 
               include only the revenues allocable to the Royalty Product as 
               determined in accordance with CCD's standard accounting 
               methods and recognized accounting principles.  Where a product 
               consists of a combination of different groups of components, 
               each used for the measurement of a different analyte, the 
               components for measurement of each particular analyte shall be 
               considered as a separate product in determining whether such 
               components constitute a Royalty Product, and the revenue 
               attributable to such a group of components shall be determined 
               by dividing the revenue for the entire product by the number 
               of different analytes which can be measured thereby.  Where a 
               Royalty Product is used by CCD or one of its Affiliates or 
               sublicensees to provide a service to a third party, the Net 
               Sales attributable to such Royalty Product shall be determined 
               based on the amount that would have been charged for sale of a 
               similar volume of such Royalty Product to a non-affiliated 
               third party in an arms'-length transaction.

         (h)  "Royalty Product" shall mean either a "Patent-Protected Royalty 
               Product" or an "Unprotected Royalty Product."  
               "Patent-Protected Royalty Product" shall mean a product the 
               sale or use of which is covered by a valid claim of an 
               unexpired Licensed Patent.  "Unprotected Royalty Product" 
               means a product the sale or use of which would be covered by a 
               valid claim of an


                                          3
<PAGE>
               unexpired Licensed Patent if such product were sold or used in a
               Designated Country, but which is not covered by a valid 
               claim of a Licensed Patent in the country in which such 
               product is actually sold or in the country in which such 
               product is actually used.

         (i)  "Strategic Exit Fee" shall mean, as to any Royalty Project, the 
               amount specified in Attachment B hereto as the fee to be paid 
               to Ciba by CCD if CCD, after exercising the CCD License Option 
               with respect to such Royalty Project, abandons development of 
               the technology resulting from such Royalty Project prior to 
               commercial launch of a product incorporating such technology, 
               for reasons other than lack of technical success.

         (j)  "Technical Exit Fee" shall mean, as to any Royalty Project, the 
               amount specified in   Attachment B hereto as the fee to be 
               paid to Ciba by CCD if CCD, after exercising the CCD License 
               Option with respect to such Royalty Project, abandons 
               development of the technology resulting from such Royalty 
               Project prior to commercial launch of a product incorporating 
               such technology, due to lack of technical success in such 
               development.

         (k)  "Technology Delivery Date" shall have the meaning specified in 
               Article 5.1 hereof.

         (l)  "Technology Transfer Criteria" shall mean, as to any Royalty 
               Project, the technical criteria specified in Attachment A 
               hereto to be satisfied through Ciba's research program prior 
               to transfer of the technology resulting from such Royalty 
               Project to CCD for further development into commercial 
               products.

         (m)  "Technology Transfer Date" shall mean, as to any Royalty 
               Project, the date established as such pursuant to Article 5.2 
               hereof.


                                          4

<PAGE>

2.  IDENTIFICATION OF ROYALTY PROJECTS

    2.1  Ciba shall inform CCD periodically (at least once a year) in the form
         of an overview (in writing) about CRU projects and technology possibly
         of strategic interest to CCD.

    2.2  CCD likewise shall inform Ciba periodically (at least once a year,
         preferably during the project management meetings provided for in
         Article 3.2 hereof) in the form of an overview (in writing) about its
         projects, technology, and technical problems which CCD considers
         possibly relevant for CRU projects and of interest to Ciba.

    2.3  In order to understand each other's positions, the parties shall meet
         to discuss the projects contained in the overviews and to exchange
         opinions on technology of mutual interest.  In preparation for such
         meetings, documentation and data in sufficient detail shall be
         exchanged at least three weeks before the meetings.  Minutes,
         including recommendations regarding Royalty Projects, shall be written
         and approved by the parties within three weeks after the meetings.

    2.4  If a CRU project is of interest to CCD and Ciba is willing to consider
         CCD's objectives to be included into the framework of such project,
         the parties shall negotiate in good faith with respect to the terms on
         which such project could become a Royalty Project under this
         Agreement.  In such cases, the parties shall endeavor to agree within
         three months on the specific details for such project to be included
         in Attachments A and B. The specific details shall include: research
         objectives, scope of applications, expected Technology Transfer Date,
         present status and technical milestones, project management structure,
         Technology Transfer Criteria, intellectual property of each party to
         be made available for use in the Royalty Project and third party
         intellectual property to be acquired (to the extent need for such
         intellectual property is known to either part), amounts of the
         Strategic Exit Fee and the Technical Exit Fee and the royalty rates
         applicable to products resulting from such Royalty Project.


                                          5

<PAGE>

    2.5  In case Ciba is not willing to consider a project to become a Royalty
         Project, CCD may propose such project to become a Project under the
         CRU Research-Funding Agreement of even date herewith.

    2.6  Both parties shall inform each other in writing, as promptly as may be
         reasonably practicable, on projects and technologies of potential
         mutual interest outside of the periodic information procedure provided
         for in Articles 2.1 through 2.3, in order not to lose time for the
         exploitation of the potential of such projects and technologies.

3.  PROJECT MANAGEMENT

    3.1  Ciba shall perform its research work for Royalty Projects in such a
         manner as to give due consideration to CCD's interests.

    3.2  Ciba shall inform CCD periodically (at least twice a year) during
         project management meetings on the progress and status of the Royalty
         Projects.  Ciba shall also inform CCD in writing, without delay, about
         changes needed in Royalty Projects which may be necessary due to
         scientific reasons or other unexpected circumstances.  The parties
         shall discuss and agree on any changes needed in Attachment A during
         the course of the Royalty Projects.

    3.3  Ciba shall inform CCD in writing as promptly as is practicable about
         contemplated strategic redirection of Ciba's interest in such projects
         which may have an impact on CCD's interest in having a project remain
         a Royalty Project as well as about the contemplated termination of a
         Royalty Project.  Work for CCD's purposes under a Royalty Project
         shall continue, however, for at least six (6) months after Ciba has
         decided and informed CCD in writing of such decision to redirect or
         terminate such project.

    3.4  In cases where a Royalty Project has been redirected by Ciba, CCD
         shall have the option either to terminate such a project as a Royalty
         Project or to propose amendments to Attachments A and B for such


                                          6

 <PAGE>

         redirected project to continue as a Royalty Project.  The parties
         shall negotiate in good faith with respect to any such proposed
         amendments and shall endeavor to reach agreement thereon within three
         (3) months.  If the parties are unable to reach agreement on such
         amendments, such project shall terminate as a Royalty Project at the
         end of the six-month period specified in Article 3.3.

    3.5  CCD shall inform Ciba in writing as promptly as is practicable if CCD
         wishes at any time to terminate a Royalty Project.

    3.6  CCD may request a re-direction of a Royalty Project.  In such cases
         the parties will negotiate in good faith revised Attachments A and B
         with respect to such Royalty Project.  Unless new terms shall be
         negotiated within three (3) months, the Royalty Project in question
         shall be terminated.

    3.7  In case Ciba's work on a Royalty Project is terminated before the
         Technology Transfer Date, CCD - at its option - may request to acquire
         rights to the technology and know-how so far developed by Ciba for use
         in Diagnostics.  In such a case the parties will negotiate in good
         faith the terms for such grant of rights, taking into account (a) the
         original terms of this Agreement applicable to such Royalty Project
         upon completion by Ciba of all work necessary to satisfy the
         Technology Transfer Criteria and (b) an appropriate reduction of CCD's
         cost to take into account the stage of completion of such Royalty
         Project at the time of termination of Ciba's work and the work
         remaining to satisfy the Technology Transfer Criteria. CCD may
         thereafter complete the project by itself or propose a project under
         the CRU Research Funding Agreement. Ciba shall not unreasonably refuse
         to continue technical support for a terminated Royalty Project on a
         funded basis under the CRU Research Funding Agreement for such period
         as may be reasonably necessary for CCD to develop internal resources
         to take over such work.


                                          7

<PAGE>

4.  TREATMENT OF INTELLECTUAL PROPERTY RIGHTS

    4.1  Any and all intellectual property, including, but not limited to,
         patents, trade secrets and copyrights, that has been, is or will be
         generated, developed or created by Ciba within the scope of Royalty
         Projects shall be the property of Ciba, provided that any invention
         made jointly by one or more employees of Ciba and one or more
         employees of CCD shall be the joint property of Ciba and CCD.

    4.2  Subject to any licenses granted under Article 3.7 or Article 4.4, Ciba
         shall be free to exploit any and all intellectual property as
         described under Article 4.1 for its own businesses.

    4.3  Intellectual property rights, whether protected by patent or not, that
         are now or hereafter jointly owned by CCD and Ciba shall be freely
         used by either co-owner, unless the parties hereafter agree that one
         party's rights to a specified invention shall be exclusive in a
         specified field or fields.  Royalties and license fees received by
         either party from the licensing of jointly-owned patents to third
         parties shall be shared equally between the parties.

    4.4  Ciba grants CCD an option for a license (the "CCD License Option") to
         all Ciba intellectual property, whether patented or not, which shall
         be granted for exclusive worldwide use (unless a non-exclusive license
         is agreed to at the start of such Royalty Project), with the right to
         grant sublicenses, in Diagnostics, within the scope of each Royalty
         Project set forth in Attachment A, including without limitation the
         patents and patent applications described in Attachment A. For each
         Royalty Project the terms of such license shall be as set, forth in
         Attachment B and the other provisions of this Agreement.  The CCD
         License Option for each Royalty Project shall remain valid for twelve
         (12) months after the Technology Transfer Date for such Royalty
         Project.

    4.5  If CCD intends to distribute a Royalty Product for veterinary health
         through a third party, Ciba shall have the right of first negotiation
         to


                                          8

<PAGE>

         distribute such product, for a period of six months after receipt of
         notice from CCD of CCD's wish to negotiate a distribution agreement
         for such product.

    4.6  In case CCD does not exercise the CCD License Option with respect to a
         Royalty Project, Ciba shall be free to exploit its intellectual
         property resulting from such Royalty Project for commercialization in
         Diagnostics.  In such a case Ciba will remunerate CCD out of income
         from the commercialization of the Royalty Project in Diagnostics for
         relevant contributions made by CCD in guiding the direction of Ciba's
         research for the Royalty Project.  The parties will negotiate in good
         faith such remuneration prior to commercialization by Ciba or their
         sublicensees.  In addition, if after the Technology Delivery Date with
         respect to a Royalty Project, CCD invents any improvements to the Ciba
         technology resulting from such Royalty Project, upon CCD's failure to
         exercise the CCD License Option CCD shall grant Ciba a non-exclusive
         license to practice such CCD inventions, with the right to grant
         sublicenses in connection with commercialization of the Ciba
         technology by a third party.  If Ciba or an affiliate commercializes
         the technology resulting from such Royalty Project and makes use of
         the CCD inventions, CCD shall be paid a reasonable royalty to be
         negotiated by the parties in good faith.  If Ciba licenses its
         technology resulting from such Royalty Project together with CCD
         inventions to a third party upon terms more favorable to Ciba than the
         terms set forth in Attachment B with respect to such Royalty Project,
         Ciba's revenue resulting from the difference between such improved
         terms and the terms as set forth in Attachment B shall be shared
         equally between Ciba and CCD.  Except as expressly provided in this
         Article 4.6, nothing herein shall require CCD to grant to Ciba a
         license under any CCD intellectual property in the field of
         Diagnostics.

    4.7  Ciba shall have the exclusive right and obligation:

         (a)  to file at its cost and expense applications for letters patent
              on any patentable inventions made by Ciba in carrying out Royalty


                                          9

<PAGE>

              Projects, including their use in Diagnostics, in the United
              States of America and in each other PCT country in which CCD has
              an Affiliate, distributor or sales representative.  Ciba shall
              consult with CCD regarding additional countries in which such
              patent applications should be filed.  Should CCD wish to include
              additional countries where Ciba does not intend to file, CCD
              shall have the option to have assigned the patent rights in such
              countries and to file at its cost and expense patent applications
              in such countries.

         (b)  to prosecute its pending and new patent applications and to
              respond to oppositions filed by third parties against the grant
              of letters patent for such applications.

         (c)  to maintain in force its letters patent by duly filing all 
               necessary papers and paying the fees required by the patent 
               laws of the particular country in which such letters patent 
               were granted.

         Ciba shall notify CCD in a timely manner of any decision to abandon a
         pending patent application or an issued patent licensed to CCD
         hereunder or for which CCD has an option for a license hereunder.
         Thereafter, CCD shall have the option to have assigned the respective
         patent rights and, at its cost and expense, to continue to prosecute
         patent applications or to keep the issued patents in force.  Ciba
         shall have a non-exclusive, royalty-free license, with sublicensing
         rights, in fields of use other than Diagnostics, under all patents
         filed by or assigned to CCD hereunder.

    4.8  In cases where Ciba's intellectual property within the scope of a
         Royalty Project is licensed from a third party, Ciba shall undertake
         commercially reasonable efforts - as within its usual conduct of
         business - to secure sublicensing rights to CCD for use of such
         intellectual property in Diagnostics or to assist CCD in obtaining a
         direct license to such intellectual property for use in Diagnostics.


                                          10

<PAGE>

    4.9  It is understood that within the scope of a Royalty Project, Ciba
         shall make available to CCD for use in Diagnostics intellectual
         property, whether patented or not, which was generated or acquired by
         Ciba's CRU whether before or after the start of this Agreement or of
         any Royalty Project, provided that if Ciba is prohibited from making
         any such intellectual property available to CCD by any agreement with
         a third party entered into before the identification of such
         intellectual property as being needed by CCD hereunder, Ciba shall be
         required only to use commercially reasonable efforts to obtain the
         consent of such third party to the grant of a license to CCD.
         Intellectual property developed or acquired by a division or
         functional unit of Ciba independently of Ciba's CRU and without use of
         the results of any Royalty Project ("Ciba Non-CRU Intellectual
         Property") after January 4, 1995 may not be available for use by CCD
         hereunder if the management of the division or functional unit which
         developed or acquired such intellectual property determines that the
         financial or strategic business interests of such division or
         functional unit will be materially harmed by the inclusion of such
         intellectual property in the license hereunder.  Ciba represents that
         the management of CRU is not aware at the date hereof of any Ciba
         Non-CRU Intellectual Property which is likely to be needed by CCD in
         connection with a Royalty Project, and Ciba agrees to notify CCD
         within thirty (30) days of the management of CRU becoming aware of any
         Ciba Non-CRU Intellectual Property that is relevant to the
         commercialization in Diagnostics of the results of a Royalty Project.
         The royalties specified in Attachment B hereto shall be the sole
         compensation to Ciba for the use by CCD of any and all Ciba
         intellectual property in connection with products resulting from a
         Royalty Project and shall be in lieu of, and not in addition to, any
         royalties payable under the 1985 Research Agreement.

    4.10 CCD shall grant Ciba a first right of negotiation, prior to CCD
         negotiating a license with any third party other than an Affiliate, to
         obtain a worldwide non-exclusive license, with no right to sublicense,
         for use outside Diagnostics of patented and non-patented intellectual


                                          11

<PAGE>

         property related to Royalty Projects contributed or generated by CCD
         prior to or during the time that Ciba is actively involved in a
         Royalty Project and needed by Ciba in order to develop, make, have
         made, use and sell non-Diagnostics products incorporating Ciba's
         technology resulting from such Royalty Project, against an adequate
         royalty rate to be negotiated in good faith, provided that if CCD is
         prohibited from making any such intellectual property available to
         Ciba by any agreement with a third party entered into before the
         identification of such intellectual property as being needed by Ciba
         hereunder, CCD shall be required only to use commercially reasonable
         efforts to obtain the consent of such third party to the grant of a
         license to Ciba.

    4.11 In cases where CCD's intellectual property needed by Ciba for use in
         commercializing non-Diagnostics products resulting from Royalty
         Projects is licensed from a third party, CCD shall undertake
         commercially reasonable efforts - as within its usual conduct of
         business - to secure sublicensing rights to Ciba for use of such
         intellectual property outside Diagnostics or to assist Ciba in
         obtaining a direct license to such intellectual property for use
         outside Diagnostics.

5.  TECHNOLOGY TRANSFER AND COMMERCIALIZATION OF THE TECHNOLOGY

    5.1  When Ciba believes that the Technology Transfer Criteria have been met
         for any Royalty Project, Ciba shall so advise CCD in writing, and
         shall deliver to CCD with such notice all relevant documentation
         giving evidence of such fact, together with all information and
         materials resulting from such Royalty Project which are necessary for
         CCD to evaluate and further develop the technology resulting from such
         Royalty Project, the date of such delivery being referred to herein as
         the Technology Delivery Date.

    5.2  At the latest within two (2) months after the Technology Delivery
         Date, CCD shall notify Ciba in writing whether or not CCD agrees that
         the Technology Transfer Criteria are met.  In case CCD is of the
         opinion that the Technology Transfer Criteria are not met, such notice
         shall be


                                          12

<PAGE>

         accompanied by CCD's statement in writing on the rationale for its
         opinion and its position regarding whether the Royalty Project should
         be continued or terminated.  If CCD agrees that the Technology
         Transfer Criteria have been met, the date of CCD's notice shall be the
         Technology Transfer Date.

    5.3  If CCD is of the opinion that the Technology Transfer Criteria with
         respect to a Royalty Project have not been met, Ciba at its option may
         either agree to continue the research phase (in which case the parties
         shall agree on the scope of the additional research work needed and
         the provisions of Articles 5.1 and 5.2 shall be applicable upon
         completion thereof) or inform CCD in writing that Ciba will terminate
         the Royalty Project (in which case Article 3.7 shall be applicable).

    5.4  Within one year from the Technology Transfer Date with respect to a
         Royalty Project, CCD shall exercise the CCD License Option by written
         notice to Ciba.  If CCD does not so exercise the CCD License Option
         for a Royalty Project within such period, CCD shall have no further
         rights under this Agreement with respect to the Ciba intellectual
         property developed in the course of such Royalty Project.

    5.5  From and after the exercise of the CCD License Option with respect to
         a Royalty Project, CCD shall report yearly to Ciba on the progress of
         CCD's development program with respect to the technology resulting
         from such Royalty Project.  At the time of exercise of the CCD License
         Option, CCD shall notify Ciba of the planned date for commercial
         launch of the product or products to be developed.  At the conclusion
         of Stage II of the development plan, as defined in CCD's internal
         procedure designated the "Innovation Process" as in effect on the date
         hereof and which typically should occur within twenty-four months
         after the Technology Transfer Date, CCD shall notify Ciba in writing
         of any change in the planned commercial launch date. Thereafter, the
         planned commercial launch date may be revised as reasonably necessary
         due to technical difficulty in the development program.


                                          13

<PAGE>

    5.6  If CCD fails to launch a commercial product using technology resulting
         from a Royalty Project by the planned launch date notified to Ciba at
         the end of Stage II of CCD's, development plan, as revised in
         accordance with the provisions of Article 5.5, CCD shall pay to Ciba,
         on each anniversary of such planned launch date until the actual
         commercial launch, the License Maintenance Fee specified in Attachment
         B with respect to such Royalty Project.  Such License Maintenance Fee
         shall be fully creditable against royalties thereafter becoming due
         with respect to Royalty Products resulting from such Royalty Project,
         provided that such credit shall not be applied to more than fifty
         percent (50%) of any installment of such royalties.

    5.7  If, after CCD has exercised the CCD License Option with respect to a
         Royalty Project, CCD ceases to pursue development of a commercial
         product using the technology resulting from such Royalty Project, CCD
         shall pay to Ciba (a) if such cessation is the result of a lack of
         technical success in development, the Technical Exit Fee specified in
         Attachment B for such Royalty Project, or (b) if such cessation is for
         any other reason, the Strategic Exit Fee specified in Attachment B for
         such Royalty Project, and in either case CCD's license with respect to
         the technology resulting from such Royalty Project shall continue.  If
         at any time CCD or a CCD Affiliate or sublicensee launches a
         commercial product using technology resulting from a Royalty Project
         with respect to which a Strategic Exit Fee or Technical Exit Fee has
         been paid, such fee shall be refunded.

    5.8  Notwithstanding the provisions of Article 5.7, if in connection with
         any Royalty Project, Ciba has not obtained patent protection in a
         Designated Country for the products under development by CCD, or if
         CCD has been unable to obtain a license to necessary third party
         technology on commercially reasonable terms, or if Ciba has been
         unable to obtain a consent of a third party required to license
         necessary Ciba technology to CCD or a consent of a Ciba division's or
         functional unit's management to license Ciba Non-CRU Intellectual
         Property to


                                          14

<PAGE>

    CCD, no Strategic Exit Fee or Technical Exit Fee shall be payable by
    CCD in the event of cessation of its development program.

6.  PAYMENT OF ROYALTIES

    6.1  CCD shall pay to Ciba a royalty on the Net Sales of Royalty Products
         sold to third parties by CCD and its Affiliates and sublicensees or
         used by CCD and its Affiliates and sublicensees in providing services
         to third parties.  The royalty rate shall be agreed upon by the
         parties for each specific Royalty Project before its initiation in
         accordance with Article 2.4 and shall for Unprotected Royalty Products
         be fifty percent (50%) of the rate agreed upon for Patent-Protected
         Royalty Products.  If so agreed by the parties at the start of a
         Royalty Project, for specific Royalty Projects, CCD shall have a
         non-exclusive license, with the right to grant sublicenses, at a lower
         royalty rate than would apply to an exclusive license, such lower rate
         to be specified in the relevant Attachment B.

    6.2  The royalties agreed upon under this Agreement for each Royalty
         Project shall be payable in each country as follows:

         (a)  with respect to sales in each country with patent protection, for
              the duration of the relevant patent(s), and

         (b)  with respect to sales in any country of the world without patent
              protection, for a duration of seven (7) years from the day of the
              first commercial introduction of any Unprotected Royalty Product
              resulting from such Royalty Project.

    6.3  After the first commercial sale of a Royalty Product resulting from a
         Royalty Project, CCD shall deliver to Ciba, within sixty (60) days
         after the end of each of CCD's fiscal half-years, a written statement
         of the amount of royalties due hereunder for such period, by product,
         and shall make payment of such royalties in United States Dollars.  If
         any amount used in the calculation of royalties is denominated in a
         currency


                                          15

<PAGE>

         other than United States Dollars, such amount shall be translated into
         United States Dollars in accordance with a method generally recognized
         and consistently used by CCD in the preparation of its audited
         financial statements.  If governmental regulations prevent remittance
         from a foreign country with respect to sales made in that country, the
         obligation under this Agreement to pay royalties in respect of sales
         in that country shall be suspended (but royalties shall continue to
         accrue) until such remittances are possible, and Ciba shall have the
         right, upon giving notice to CCD, to receive payment in that country
         in the local currency.

    6.4  Ciba shall have the right to have an independent certified public
         accountant, to which CCD has no reasonable objection, inspect during
         ordinary business hours relevant books and records of account of CCD,
         its Affiliates and sublicensees to determine whether appropriate
         accounting and payment have been made to Ciba, such inspection to be
         made within one year after the end of the fiscal year to which such
         books and records relate.  Said independent certified public
         accountant shall treat as confidential all information received in
         connection with such inspection, and shall disclose to Ciba only
         whether there has been a royalty underpayment and, if so, the amount
         thereof.  The fees and expenses of such accountant performing such
         verification shall be borne by Ciba, unless such audit shows an
         underpayment of seven and one-half percent (7 1/2%) or more.  In the
         case of any sublicense by CCD to any of its Affiliates or third
         parties, CCD shall be responsible to Ciba for the adherence by such
         Affiliates and sublicensees to the same obligations as those that
         apply to CCD under this Agreement.  CCD shall keep Ciba informed as to
         the identity of each Affiliate and third party so sublicensed.

    6.5  In case new applications in Diagnostics of the technology arising from
         a Royalty Project become possible, which applications could not be
         identified at the initiation of such Royalty Projects, the parties
         will agree in good faith on the royalty rates for such applications.


                                          16

<PAGE>

7.  LIABILITY

    CCD shall hold Ciba and its Affiliates and their officers and employees
    harmless from and against any and all liability, costs, assessments, fines,
    claims, actions, damages and expenses (including attorney's fees and costs
    of investigation), including without limitation all product liability
    claims and damages, arising in relation to the development, manufacture,
    sublicense, use or sale by CCD of products incorporating the technology
    resulting from a Royalty Project for use in Diagnostics, provided that
    nothing herein shall require CCD to indemnify any party against such
    liability, claims, etc., arising out of the gross negligence or willful
    misconduct of such party, and provided, further, that any party seeking
    indemnification hereunder shall promptly notify CCD of any claim for which
    indemnification may be sought, shall permit CCD to assume the defense of
    such claim with counsel of CCD's choice and shall cooperate as reasonably
    requested by CCD in such defense.

8.  INFRINGEMENT OF PATENT RIGHTS OF THIRD PARTIES

    8.1  Ciba makes no representation or warranty that the practice of the
         technology or manufacture, sale or use of the products resulting from
         the Royalty Projects in Diagnostics, whether patented or not, does not
         or will not infringe the rights of any third party.

    8.2  In the event that a third party shall assert that the practice of any
         of the technology or sale or use of any of the products resulting from
         a Royalty Project for use in Diagnostics infringes any right of such
         third party, the party having the knowledge thereof shall forthwith
         give notice to the other.  CCD shall have the exclusive right to
         defend or otherwise dispose of such claim, provided that CCD shall
         consult with Ciba regarding such defense or disposition.  CCD shall be
         entitled to offset fifty (50) percent of all reasonable defense costs
         and all reasonable amounts paid in settlement of such claim, including
         license fees and royalties under an appropriate license agreement
         entered into with the third party in connection with such settlement,
         or paid as damages


                                          17

<PAGE>

         for which CCD is held liable, against future royalties payable to Ciba
         under this Agreement.

    8.3  The License Maintenance Fees provided for in Article 5.6 hereof shall
         not be payable with respect to any Royalty Project during any period
         when CCD is prevented from practicing the technology arising from such
         Royalty Project by reason of a claimed infringement of the rights of a
         third party, and the due date of the first License Maintenance Fee
         with respect to any Royalty Project shall be deferred to the extent of
         any delay in CCD's product development plans arising from such claimed
         infringement.  If a claim of infringement affects only some of the
         applications of such technology, the parties hereto shall negotiate in
         good faith with respect to an appropriate reduction in the amount of
         the License Maintenance Fee.  If CCD abandons the development of the
         technology arising out of a Royalty Project because of inability to
         obtain a license under third party rights necessary to the success of
         such development, no Strategic Exit Fee or Technical Exit Fee shall be
         payable to Ciba as a result of such abandonment.

9.  INFRINGEMENT OF PATENT RIGHTS BY THIRD PARTIES

    In the event either party becomes aware that a third party is infringing
    any patented intellectual property related to technology or products
    resulting from a Royalty Project for use in Diagnostics, the parties shall
    confer as to the manner in which they will proceed with respect to such
    infringement.  Ciba shall have the exclusive right to commence and
    prosecute an action for patent infringement against such infringing party
    (provided that Ciba shall consult with CCD with respect to such
    commencement and prosecution), except that CCD shall have the right to
    commence and prosecute a counterclaim in any suit defended by CCD pursuant
    to Article 8 hereof (provided that CCD shall consult with Ciba with respect
    to such commencement and prosecution).  If Ciba undertakes such action or
    CCD asserts such counterclaim, any damages recovered first shall be applied
    to reimburse such party all expenses of such action not otherwise
    reimbursed and next shall be paid to Ciba and CCD in proportion to


                                          18

<PAGE>

    their actual damages upon which such recovery was based.  If Ciba fails to
    commence action to prevent such infringement within ninety (90) days after
    learning of the facts constituting such infringement, or if Ciba agrees to
    settle any such action on a basis which would allow such infringement to
    continue, then CCD shall cease to be obligated to pay royalties in respect
    of any product or service incorporating technology or products resulting
    from a Royalty Project until such infringement shall have ceased.

10. CONFIDENTIALITY

    10.1 Ciba and CCD agree that they will each treat as strictly confidential
         any and all proprietary information and data disclosed by the other
         party in connection with the subject matter of this Agreement or
         resulting from their activities hereunder (the "Information") and they
         will not use such Information or disclose such Information to any
         third party without the prior written consent of the other party,
         except as may be required or permitted in the performance of this
         Agreement or by applicable law.

    10.2 Each party agrees that it will take all reasonable precautions to
         ensure that it or any of its employees receiving such Information
         disclosed pursuant to this Agreement will maintain the confidentiality
         thereof.

    10.3 Both parties agree that Information may be disclosed either orally or
         in writing.  When disclosed in writing, Information will be
         identified, labelled and stamped as confidential.  When disclosed
         orally, such Information will first be identified as confidential at
         the time of oral disclosure, with subsequent confirmation in writing
         within thirty (30) days after such disclosure.

    10.4 It is agreed, however, that such Information:

         (a)  which at the time of disclosure is published by a third party or
              is otherwise in the public domain;


                                          19

<PAGE>

         (b)  which after disclosure becomes part of the public domain
              otherwise than through a breach of this Agreement by the receiving
              party;

         (c)  which was known to the receiving party prior to receipt from the
              disclosing party, provided that such prior knowledge can be
              adequately substantiated by documentary evidence antedating the
              disclosure by the other party;

         (d)  which is disclosed to the receiving party by a third party (other
              than employees or agents of either party) who, in making such
              Information available to the receiving party, is not in violation
              of any obligation of confidentiality to the disclosing party
              under this Agreement;

         (e)  which is shown by competent written evidence to be independently
              developed by the receiving party; or

         (f)  which the receiving party is required to divulge either by a
              court of law or in order to comply with any applicable law or
              regulation (after providing the disclosing party with reasonable
              notice of such requirement to divulge and with an opportunity to
              obtain a protective order),

shall not be subject to the provisions of this Agreement.

    10.5 Ciba recognizes the legitimate interest of CCD to publish its
         Information in the field of Diagnostics.  On the other hand, CCD 
         recognizes Ciba's interest that publications be made and lectures be 
         given only to the extent that it has reasonably safeguarded the 
         Information proprietary to Ciba through patent protection or otherwise 
         so that third parties cannot make commercial and/or industrial use of 
         Ciba's findings.  For this purpose, CCD shall ensure that Ciba shall 
         have the opportunity to comment in advance on any publication or oral 
         presentation in public including disclosure of any Information of Ciba 
         relating to technology/products resulting from a Royalty Project and


                                          20

<PAGE>

         that no such publication or presentation shall be made by CCD without
         Ciba's prior written consent.  Ciba shall not unreasonably withhold or
         delay its consent to such publication or presentation.  CCD shall
         submit to Ciba sixty (60) days in advance its request for such
         publication or presentation.

11. MATERIAL TRANSFER

    From time to time in connection with the activities contemplated by this
    Agreement, each party may transfer to the other samples of proprietary
    materials developed by the providing party.  Except as otherwise expressly
    provided herein or in any applicable license or supply agreement between
    the parties, such materials and any materials derived therefrom a) shall
    remain the property of the providing party, b) shall be used only for
    purposes specified at the time such materials are provided, c) shall not be
    transferred to any third party without the consent of the party by whom
    such materials were provided, and d) shall be destroyed or returned to the
    providing party upon request by the providing party.  Unless otherwise
    agreed in writing with respect to particular materials, the providing party
    shall have a non-exclusive, royalty-free license to any inventions made by
    the other party through use of the providing party's proprietary materials,
    subject to the provisions of this Agreement.

12. TERM OF AGREEMENT

    12.1 Subject to the provisions of Article 3, each party shall have the
         right to terminate this Agreement upon six (6) months prior written
         notice.

    12.2 In the event of a termination of this Agreement, all licenses, options
         and rights of negotiation granted hereunder with respect to Royalty
         Projects agreed upon during the term hereof shall continue upon and
         subject to the terms of this Agreement.


                                          21

<PAGE>

13. LIMITATION OF ASSIGNMENT

    This Agreement is personal in nature and neither of the parties shall,
    without the consent of the other, assign or transfer its rights or
    obligations hereunder to another company or person, except as herein
    expressly provided or permitted, except that (a) either party may transfer
    all or any portion of its rights and obligations to any of its Affiliates
    which shall agree to be bound by the provisions hereof relating to the
    assigned rights or obligations, in which event the assigning party shall
    continue to be responsible for the performance by such Affiliate of its
    obligations hereunder, and (b) CCD's rights hereunder with respect to
    Royalty Projects which have been terminated or for which Ciba has proposed
    that the Technology Transfer Criteria have been satisfied shall be
    assignable to a successor to substantially the whole of one of its lines of
    business.  In the event that Ciba wishes to transfer the responsibility for
    conducting the research phase of a Royalty Project to one of its
    Affiliates, Ciba will first consult with CCD regarding the possible impact
    of such transfer on the timely completion of the Royalty Project.  If CCD
    believes that CCD itself would be better able to complete such Royalty
    Project than the Ciba Affiliate to whom Ciba proposes to transfer the
    Project, Ciba will permit CCD to take over completion of the Royalty
    Project, and the parties will negotiate in good faith with respect to the
    terms on which Ciba will transfer to CCD the rights in Diagnostics to the
    work already completed by Ciba, in accordance with the provisions of
    Article 3.7. Subject to the foregoing provisions of this Section, this
    Agreement shall be binding upon and inure to the benefit of the parties
    hereto and their respective successors and assignees.

14. ENTIRE AGREEMENT; MODIFICATION AND WAIVER

    This Agreement is the entire agreement between the parties with respect to
    the subject matter hereof and supersedes any prior negotiations and
    agreements, provided that all licenses granted by either party to the other
    under the 1985 Research Agreement remain in effect.  This Agreement may not
    be modified or amended in any way except by mutual written agreement of the
    parties.  The failure of either party to enforce any provision hereof, or
    any right hereunder, shall not be construed as a waiver of such provision
    or right.


                                          22

<PAGE>

 15. GOVERNING LAW; JURISDICTION

    This Agreement shall be governed by, and construed in accordance with, the
    laws of the State of Delaware applicable to contracts executed and to be
    fully performed in that State.  All actions and proceedings arising out of
    or relating to this Agreement shall be brought by the parties and heard and
    determined only in a Delaware state court or a federal court sitting in
    that State and the parties hereto consent to jurisdiction before and waive
    any objections to the jurisdiction of any such court.

16. WAIVER OF JURY TRIAL

    Each of the parties of this agreement hereby irrevocably waives all right
    to trial by jury in any action, proceeding or counterclaim (whether based
    on contract, tort, or otherwise) arising out of or relating to this
    Agreement or the actions of any of them in the negotiation, administration,
    performance and enforcement hereof.

IN WITNESS WHEREOF, the parties have executed this Agreement or caused their
duly authorized representatives to execute this Agreement as of the date first
above written.


    CIBA CORNING DIAGNOSTICS                          CIBA-GEIGY Limited
         CORP.


    By:  /s/ Richard D. Falb                          By:  /s/ D. Bellus
       ---------------------------------                 --------------------
         Richard D. Falb, Ph.D.                            Prof. D. Bellus
         Senior Vice President, Research                   Head, CRU
         & Development

                                                      and

                                                      By:  /s/ A. Egloff
                                                         --------------------
                                                           Dr. A. Egloff
                                                           Legal Counsel, CRU



    Attachment A               Royalty Projects
    Attachment B               Financial Terms


                                          23

<PAGE>

Royalty Projects to be included in Attachments A and B



1.  [Confidential Treatment Requested] For [Confidential Treatment Requested]

2.  [Confidential Treatment Requested] for [Confidential Treatment Requested]

3.  [Confidential Treatment Requested] for [Confidential Treatment Requested]

4.  [Confidential Treatment Requested] Systems for [Confidential Treatment
Requested]


<PAGE>

Attachment 1                      Confidential
(Royalty Project Agreement)            [Confidential Treatment Requested] for
                                       [Confidential Treatment Requested]

Title:  [Confidential Treatment Requested]             Royalty Project for Ciba
for [Confidential Treatment Requested]                 Corning Diagnostics
[Confidential Treatment Requested]
(cf. Attachments A2 & A3 for other uses of
[Confidential Treatment Requested]
                                                       Status November 1995


Approved by:
                                        Project Management:


__________________   ______________     CCD: [Confidential Treatment Requested]
SVP, R&D, CCD        Head CRU, Ciba
30.11.95             30.11.95           Ciba: [Confidential Treatment Requested]


Working basis agreed upon:  Exclusive




Objective

- -    Develop expertise and demonstrate feasibility of concepts in the field of
     analytical methods based on [Confidential Treatment Requested] recognition,
     advanced [Confidential Treatment Requested] detection schemes and
     [Confidential Treatment Requested] handling systems.

- -    Develop and explore functional models of such systems with respect to human
     diagnostics.  Characterize performance range using [Confidential Treatment
     Requested] representing the following criteria:  Assay sensitivity, dynamic
     range, suitability for low molecular weight analytes, assay format.




Expected Technology Transfer Date:            [Confidential Treatment Requested]




Present Status

Patents:

- -    Method for the detection of [Confidential Treatment Requested] in the 
     [Confidential Treatment Requested] field of a [Confidential Treatment 
     Requested] Application [Confidential Treatment Requested] contract)

- -    Method for using an [Confidential Treatment Requested] for the detection 
     of [Confidential Treatment Requested] in the [Confidential Treatment 
     Requested] field of a [Confidential Treatment Requested] Priority:  
     [Confidential Treatment Requested] Application [Confidential Treatment 
     Requested] contract)

<PAGE>

- -   Patent application filed for [Confidential Treatment Requested] comprising 
    one or more [Confidential Treatment Requested] used for [Confidential  
    Treatment Requested] contract)

- -   Method for detection of [Confidential Treatment Requested] in the 
    [Confidential Treatment Requested] field using [Confidential Treatment 
    Requested] for the [Confidential Treatment Requested] detection of several
    [Confidential Treatment Requested] Ciba)

- -   [Confidential Treatment Requested] for [Confidential Treatment Requested] of
    [Confidential Treatment Requested] substances [Confidential Treatment 
    Requested] Ciba)

- -   [Confidential Treatment Requested] (Ciba; in preparation)

- -   Principle design of [Confidential Treatment Requested] configuration for a
    [Confidential Treatment Requested] system [Confidential Treatment Requested]
    contract; in preparation by [Confidential Treatment Requested]



Present Status continued

Further know-how

- -    A [Confidential Treatment Requested] system has been developed and applied
     in showing advantages under realistic conditions compared to routinely used
     [Confidential Treatment Requested] such as:  [Confidential Treatment 
     Requested] information available, high precision and improved sample
     handling.  Without loss in performance, the same [Confidential Treatment 
     Requested] could be used for up to [Confidential Treatment Requested] 
     measurements.

- -    [Confidential Treatment Requested] of [Confidential Treatment Requested] 
     has been demonstrated.  The obtained [Confidential Treatment Requested] 
     performed exceptionally well and no loss of performance was observed even 
     after [Confidential Treatment Requested] measurement and regeneration 
     cycles.

- -    The immobilization of [Confidential Treatment Requested] on [Confidential 
     Treatment Requested] demonstrated the possibility to [Confidential 
     Treatment Requested] on [Confidential Treatment Requested].  With model 
     systems, the [Confidential Treatment Requested] could be reduced remarkably
     compared to conventional [Confidential Treatment Requested].

- -    For model systems, a significant simplification of [Confidential Treatment 
     Requested] has been achieved using two approaches:  a) [Confidential 
     Treatment Requested] systems comprising [Confidential Treatment Requested]
     and [Confidential Treatment Requested] b) [Confidential Treatment 
     Requested] using [Confidential Treatment Requested] to generate 
     [Confidential Treatment Requested].
<PAGE>

- -    Thorough theoretical and practical understanding of [Confidential Treatment
     Requested] from the former project [Confidential Treatment Requested] has 
     been successfully transferred to [Confidential Treatment Requested] based
     [Confidential Treatment Requested] detection schemes.

- -    [Confidential Treatment Requested] Technology:  A [Confidential Treatment 
     Requested] including [Confidential Treatment Requested] and [Confidential 
     Treatment Requested] techniques under clean room conditions as well as 
     [Confidential Treatment Requested] and [Confidential Treatment Requested]
     characterization methods have been established and applied to thorough 
     characterization.  First results are available in [Confidential Treatment 
     Requested] and [Confidential Treatment Requested] production.

- -    Expertise in development of complex [Confidential Treatment Requested] 
     based on [Confidential Treatment Requested] 


Milestones (to be updated twice a year)

Version agreed upon in Meeting of [Confidential     Completion     Responsible
Treatment Requested]


6 Months milestones

- -    Finalize the set of selected [Confidential     [Confidential  [Confidential
     Treatment Requested]                           Treatment      Treatment
                                                    Requested]     Requested]

- -    Fix the relevant precision data for the        [Confidential  [Confidential
     above assays for [Confidential Treatment       Treatment      Treatment
     Requested] criteria                            Requested]     Requested]

- -    Provide SOP and source for [Confidential       [Confidential  [Confidential
     Treatment Requested] materials for the         Treatment      Treatment
     above assays                                   Requested]     Requested]

- -    Reevaluate [Confidential Treatment             [Confidential  [Confidential
     Requested] situation on [Confidential          Treatment      Treatment
     Treatment Requested] and [Confidential         Requested]     Requested]
     Treatment Requested]

- -    Clarify relations to external partners         [Confidential  [Confidential
     with respect to short-term [Confidential       Treatment      Treatment
     Treatment Requested] supply and long term      Requested]     Requested]
     contracts.

- -    Develop system concepts regarding              [Confidential  [Confidential
     [Confidential Treatment Requested] and         Treatment      Treatment
     [Confidential Treatment Requested] and         Requested]     Requested]
     [Confidential Treatment Requested]

- -    Design first [Confidential Treatment           [Confidential  [Confidential
     Requested] system                              Treatment      Treatment
                                                    Requested]     Requested]

- -    Decide on [Confidential Treatment              [Confidential  [Confidential
     Requested] for 
<PAGE>

      [Confidential Treatment Requested]            Treatment      Treatment
                                                    Requested]     Requested]

- -    Transfer of [Confidential Treatment            [Confidential  [Confidential
     Requested] from CCD to Ciba completed          Treatment      Treatment
                                                    Requested]     Requested]

- -    [Confidential Treatment Requested]             [Confidential  [Confidential
     on [Confidential Treatment Requested]          Treatment      Treatment
     for [Confidential Treatment Requested]         Requested]     Requested]


Long term milestones

- -    Develop the product concept                    [Confidential  [Confidential
                                                    Treatment      Treatment
                                                    Requested]     Requested]

- -    Decision on    [Confidential                   [Confidential  [Confidential
                    Treatment Requested]            Treatment      Treatment
                    material & [Confidential        Requested]     Requested]
                    Treatment Requested]
                    [Confidential Treatment
                    Requested] and 
                    [Confidential Treatment 
                    Requested] configuration
                    [Confidential Treatment
                    Requested]

- -    Transfer of all [Confidential Treatment        [Confidential  [Confidential
     Requested] from CCD to Ciba completed          Treatment      Treatment
                                                    Requested]     Requested]

- -    Decide on [Confidential Treatment              [Confidential  [Confidential
     Requested]                                     Treatment      Treatment
                                                    Requested]     Requested]

- -    [Confidential Treatment Requested] &           [Confidential  [Confidential
     [Confidential Treatment Requested] for         Treatment      Treatment
     first [Confidential Treatment Requested]       Requested]     Requested]
     available

- -    Sample [Confidential Treatment                 [Confidential  [Confidential
     Requested] for [Confidential                   Treatment      Treatment
     Treatment Requested] available                 Requested]     Requested]

- -    Decision on [Confidential Treatment            [Confidential  [Confidential
     Requested]                                     Treatment      Treatment
                                                    Requested]     Requested]

- -   [Confidential Treatment Requested] on           [Confidential  [Confidential
    [Confidential Treatment Requested]              Treatment      Treatment
    developed/compared with specs.                  Requested]     Requested]

- -   Design [Confidential Treatment Requested]       [Confidential  [Confidential
                                                    Treatment      Treatment

<PAGE>

                                                    Requested]     Requested]

- -    Build [Confidential Treatment Requested]       [Confidential  [Confidential
                                                    Treatment      Treatment
                                                    Requested]     Requested]

- -    Transfer of [Confidential Treatment            [Confidential  [Confidential
     Requested] procedures                          Treatment      Treatment
                                                    Requested]     Requested]

- -    [Confidential Treatment Requested]             [Confidential  [Confidential
     developed and tested for specs on              Treatment      Treatment
     [Confidential Treatment Requested]             Requested]     Requested]


Ciba:    [Confidential Treatment Requested]
         [Confidential Treatment Requested]
CCD      [Confidential Treatment Requested]


Intellectual property from outside of the Royalty Project to be made available:

Ciba:         [Confidential Treatment Requested]
CCD:          [Confidential Treatment Requested]
Third party:  [Confidential Treatment Requested]


Management

Project Management Meetings twice a year.


Technology Transfer Criteria (Article 5.1)

- -    A [Confidential Treatment Requested] will have been set-up which is capable
     of demonstrating assay performance under stable and reproducible 
     conditions.  It will include the [Confidential Treatment Requested] and 
     [Confidential Treatment Requested] design, a [Confidential Treatment 
     Requested] system, the [Confidential Treatment Requested] system for 
     [Confidential Treatment Requested] and [Confidential Treatment Requested]
     and [Confidential Treatment Requested].  It is understood, that the main 
     purpose of the [Confidential Treatment Requested] will be to demonstrate 
     functionality and the main purpose of the [Confidential Treatment 
     Requested] to demonstrate assay performance.  Costly and voluminous 
     components, evidently not suitable for CCD's commercial use will not be 
     applied.  single source materials and chemicals are to be identified.

- -    Performance will be demonstrated using the assays and specifications listed
     below.  Multifactorial design experiments will be applied in order to 
     confirm the specs to be fulfilled.

- -    Performance to specs will be shown for the [Confidential Treatment 
     Requested] jointly as part of the transfer process at least twice.

- -    [Confidential Treatment Requested] are discussed in the biannual meetings 
     and [Confidential 

<PAGE>

     Treatment Requested] are included in the overhead slide collections.

- -    Documentation will be prepared to allow a skilled CCD technician to 
     reproduce the system and its performance in-house or to run a [Confidential
     Treatment Requested] system physically transferred to CCD.  Documentation
     will include the accumulated experience about common failure modes and 
     reliability problems encountered during the research phase as related to
     [Confidential Treatment Requested] and [Confidential Treatment Requested].


SPECIFICATIONS

1.  Calibration                   [Confidential Treatment Requested] i.e. to run
                                  [Confidential Treatment Requested]

2.  Sample size                   [Confidential Treatment Requested] per 
                                  [Confidential Treatment Requested]

3.  Mode of operation             [Confidential Treatment Requested] or 
                                  [Confidential Treatment Requested] to be
                                  fixed by the fall meeting [Confidential 
                                  Treatment Requested]

4.  Assays per chip               [Confidential Treatment Requested]

5.  Time to result                [Confidential Treatment Requested] min. 
                                  preferred)

6.  Samples                       [Confidential Treatment Requested] (will be
                                  [Confidential Treatment Requested] for final
                                  product at CCD).

7.  Assay sensitivity             [Confidential Treatment Requested] 
                                  demonstrated with [Confidential Treatment
                                  Requested]

8.  Dynamic range                 [Confidential Treatment Requested] 
                                  demonstrated with [Confidential Treatment
                                  Requested]

9.  Assay format                  [Confidential Treatment Requested] and 
                                  [Confidential Treatment Requested]

10. Low MW analyte                Demonstrated with [Confidential Treatment
                                  Requested]

11. Selectivity                   [Confidential Treatment Requested] to be 
                                  decided in [Confidential Treatment Requested]

12. Precision/Reproducibility     To be defined by [Confidential Treatment 
                                  Requested] after consulting with [Confidential
                                  Treatment Requested]

13. Experimental control          [Confidential Treatment Requested] of all 
    software                      system components/Menu for complete assays

<PAGE>

*    This spec must be feasibly reachable after development but need not be 
     demonstrated with the [Confidential Treatment Requested]

**   Reference assays fulfilling requirements of enclosed assay performance 
     chart will be developed and provided by Chiron Diagnostics as agreed 
     (see milestones).

<PAGE>

Title:  [Confidential Treatment Requested]             Royalty Project for Ciba
for [Confidential Treatment Requested]                 Corning Diagnostics
[Confidential Treatment Requested]
(cf. Attachments A2 & A3 for other uses of
[Confidential Treatment Requested]
                                                       Status November 1995


Approved by:
                                         Project Management:


    . . . . . . .       . . . . . . . . CCD:  [Confidential Treatment Requested]
    SVP, R&D, Chiron    Head CRU, Ciba
    15.12.95            15.12.95        Ciba: [Confidential Treatment Requested]

Working basis agreed upon:  Exclusive


Objective

- -    Based on expertise acquired under program A1, demonstrate feasibility of 
     concepts in the field of [Confidential Treatment Requested] of 
     [Confidential Treatment Requested] advanced [Confidential Treatment 
     Requested] schemes and [Confidential Treatment Requested] systems, with 
     special attention to [Confidential Treatment Requested] system 
     [Confidential Treatment Requested].

- -    Investigate alternative [Confidential Treatment Requested] concepts based 
     on [Confidential Treatment Requested] interactions for clinical 
     diagnostics.  Consider new achievements in [Confidential Treatment 
     Requested] diagnostics [Confidential Treatment Requested]

- -    Develop and explore functional models of an [Confidential Treatment 
     Requested] for the simultaneous analysis of [Confidential Treatment 
     Requested] (Immuno).  Potential usages include:  [Confidential Treatment
     Requested] Detection & [Confidential Treatment Requested] and [Confidential
     Treatment Requested] Detection & [Confidential Treatment Requested].


Expected Technology Transfer Date:           [Confidential Treatment Requested]


Present Status

Patents:

- -    Method for the detection of [Confidential Treatment Requested] in the 
     [Confidential Treatment Requested] field of a [Confidential Treatment 
     Requested] Application [Confidential Treatment Requested] contract)


<PAGE>

Attachment A2                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


- -  Method for using an [Confidential Treatment Requested] for the detection 
   of [Confidential Treatment Requested] in the [Confidential Treatment 
   Requested] field of a [Confidential Treatment Requested]; Priority 
   [Confidential Treatment Requested] Application [Confidential Treatment 
   Requested] contract)

- -  Patent application filed for [Confidential Treatment Requested] comprising 
   one or more [Confidential Treatment Requested] used for [Confidential 
   Treatment Requested] contract)

- -  Method for detection of [Confidential Treatment Requested] in the 
   [Confidential Treatment Requested] field using [Confidential Treatment 
   Requested] for the [Confidential Treatment Requested] detection of several 
   [Confidential Treatment Requested] Ciba)


Patents continued

[Confidential Treatment Requested] for [Confidential Treatment Requested] of 
[Confidential Treatment Requested] substances [Confidential Treatment 
Requested] Ciba)

- -  [Confidential Treatment Requested] (Ciba; in preparation)

- -  Principle design of [Confidential Treatment Requested] configuration for a 
   [Confidential Treatment Requested] system [Confidential Treatment Requested] 
   contract; in prepartion by [Confidential Treatment Requested] 

Further know-how

- -  A [Confidential Treatment Requested] system has been developed and applied, 
   showing advantages under realistic conditions compared to routinely used 
   [Confidential Treatment Requested] such as:[Confidential Treatment 
   Requested] information available, high precision and improved sample 
   handling. Without loss in performance, the same [Confidential Treatment 
   Requested] could be used for up to [Confidential Treatment Requested] 
   measurements.

- -  A detection limit of [Confidential Treatment Requested] moles [Confidential 
   Treatment Requested] labeled [Confidential Treatment Requested] of 
   [Confidential Treatment Requested] binding to protein [Confidential 
   Treatment Requested]  on a [Confidential Treatment Requested] has been 
   achieved.

- -  The principle feasibility of simultaneous assays on [Confidential Treatment 
   Requested] areas [Confidential Treatment Requested] has been demonstrated in 
   model [Confidential Treatment Requested] assay for [Confidential Treatment 
   Requested].

- -  A first [Confidential Treatment Requested] system will be developed in the 
   module [Confidential Treatment Requested] for [Confidential Treatment 
   Requested] of the Ciba/CCD royalty project (Appendix A-1).


<PAGE>

Attachment A2                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


- -  For model systems, a significant simplification of [Confidential Treatment 
   Requested] has been achieved using two approaches:  a) [Confidential 
   Treatment Requested] systems comprising [Confidential Treatment Requested] 
   and [Confidential Treatment Requested] b) [Confidential Treatment Requested] 
   using [Confidential Treatment Requested] to generate [Confidential Treatment 
   Requested].

- -  [Confidential Treatment Requested] Technology:  A [Confidential Treatment 
   Requested] including [Confidential Treatment Requested] and [Confidential 
   Treatment Requested] techniques under clean room conditions, as well as 
   [Confidential Treatment Requested] and [Confidential Treatment Requested] 
   characterization methods have been established and applied to thorough 
   characterization.  First results are available in [Confidential Treatment 
   Requested] and [Confidential Treatment Requested] production

Milestones (to be updated end of 1997)

Proposed                                      Completion             Responsible

Milestones of Attachment A1 achieved          [Confidential
                                              Treatment
                                              Requested]

Development and evaluation of novel           [Confidential
[Confidential Treatment Requested]            Treatment 
concepts for [Confidential Treatment          Requested]
Requested] and spacially [Confidential
Treatment Requested]

Minimum [Confidential Treatment Requested] 
for model assay determined

Relation between [Confidential Treatment 
Requested] and [Confidential Treatment 
Requested] between individual [Confidential 
Treatment Requested] investigated

Test of different assay formats for           [Confidential
[Confidential Treatment Requested]            Treatment
                                              Requested]

Concept for selection of [Confidential
Treatment Requested] for a sample

[Confidential Treatment Requested] and 
[Confidential Treatment Requested] or
different [Confidential Treatment
Requested] developed

Structured [Confidential Treatment Requested] [Confidential 


<PAGE>

Attachment A2                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


optimized                                    Treatment
                                             Requested]

Transfer [Confidential Treatment Requested] 
and [Confidential Treatment Requested] 
developed and tested against [Confidential 
Treatment Requested] on [Confidential 
Treatment Requested] [Confidential Treatment
Requested]

Intellectual property from outside of the Royalty Project to be
made available:

Ciba:                [Confidential Treatment Requested]
CCD:                 [Confidential Treatment Requested]
Third party:         [Confidential Treatment Requested]

Management

Project Management Meetings twice a year.

Technology Transfer Criteria (Article 5.1)

Specifications will be re-examined at the end of [Confidential Treatment 
Requested].  Significant changes to the specs will be accepted through 
[Confidential Treatment Requested].  Only modest to small changes will be 
accepted in [Confidential Treatment Requested].

- -  A [Confidential Treatment Requested] will have been set-up which is capable 
   of demonstrating throughput and assay performance under stable and 
   reproducible conditions. It will include the [Confidential Treatment 
   Requested] and [Confidential Treatment Requested], a [Confidential Treatment 
   Requested] system, the [Confidential Treatment Requested] system for 
   [Confidential Treatment Requested] and detection and experimental control 
   [Confidential Treatment Requested]. It is understood, that the main purpose 
   of the [Confidential Treatment Requested] will be to demonstrate 
   functionality and the main purpose of the [Confidential Treatment Requested] 
   to demonstrate assay performance.  Costly and voluminous components, 
   evidently not suitable for CCD's commercial use will not be applied.

- -  Performance will be demonstrated using the assays and specifications listed 
   below.

Documentation will be prepared to allow a skilled CCD technician to reproduce 
the system and its performance in-house or to run a [Confidential Treatment 
Requested] physically transferred to CCD. Documentation will include the 
accumulated experience about common failure modes and reliability problems 
encountered during the research phase as related to instrumentation and 
[Confidential Treatment Requested]

Prototypes/Boundary Assays      [Confidential Treatment Requested] or 
- --------------------------      [Confidential Treatment Requested]

Specifications
- --------------

<PAGE>

Attachment A2                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


1.  Mode of operation                 [Confidential Treatment Requested] use

2.  Multiplexity                      Up to [Confidential Treatment Requested] 
                                      per [Confidential Treatment Requested] 
                                      Processing of up to [Confidential 
                                      Treatment Requested]

3.  Temperature                       [Confidential Treatment Requested] 
                                      temperature [Confidential Treatment
                                      Requested]

4.  Sample size/OED                   [Confidential Treatment Requested]

5.  Time to first results             [Confidential Treatment Requested]

6.  Samples                           [Confidential Treatment Requested]

7.  Assay sensitivity                 [Confidential Treatment Requested] 
                                      molecules/Analyte (Input) demonstrated 
                                      with [Confidential Treatment Requested]

8.  Dynamic range                     [Confidential Treatment Requested] 
                                      detection up to [Confidential Treatment
                                      Requested] required: [Confidential 
                                      Treatment Requested] with integrated 
                                      dilution (e.g. [Confidential Treatment 
                                      Requested] demonstrated with 
                                      [Confidential Treatment Requested]

9.  Assay format                      [Confidential Treatment Requested]

10. Fluidics                          [Confidential Treatment Requested] sample 
                                      distribution

*   This spec must be feasible reachable after development but need not be 
    demonstrated with the [Confidential Treatment Requested]

**  Antibodies or antigens from prototype or marketed assays will be made 
    available by Chiron Diagnostics when ever possible in support of the 
    project milestones. In case of unavailability alternate assays will be 
    negotiated.

<PAGE>

Attachment A3                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


Title:   [Confidential Treatment Requested]     Royal Project for Ciba Corning
for [Confidential Treatment Requested]          Diagnostics

(cf Attachments A1 & A2 for other uses of 
[Confidential Treatment Requested]
                                                Status December 1995
- --------------------------------------------------------------------------------
Approved by:
                                       Project Management:

                                       CCD: [Confidential Treatment Requested]

                                       Ciba: [Confidential Treatment Requested]

___________________   ___________________
SVP, R&D, CC          Head CRU, Ciba
3.1.96                3.1.96

Working basis agreed upon:  EXCLUSIVE

OBJECTIVE

- -  Develop expertise and demonstrate feasibility of concepts in the field of 
   [Confidential Treatment Requested] methods based on [Confidential Treatment 
   Requested] recognition, advanced [Confidential Treatment Requested] 
   detection schemes and [Confidential Treatment Requested] systems that are 
   adequate for achieving [Confidential Treatment Requested] limits.

- -  To build a basis for very high [Confidential Treatment Requested] and 
   [Confidential Treatment Requested] for screening of [Confidential Treatment 
   Requested] panels to be delt with in a follow-up Royalty Project.

- -  Develop and explore functional models of an [Confidential Treatment 
   Requested] for the simultaneous analysis of [Confidential Treatment 
   Requested].  Potential usages include: [Confidential Treatment Requested] 
   detection and [Confidential Treatment Requested] quantification for the 
   [Confidential Treatment Requested] and the [Confidential Treatment 
   Requested] panel.

EXPECTED TECHNOLOGY TRANSFER DATE:     [Confidential Treatment Requested]

PRESENT STATUS

Patents:
- --------

- -  Method for the detection of [Confidential Treatment Requested] in the 
   [Confidential Treatment Requested] field of a [Confidential Treatment 
   Requested].  Application 

<PAGE>

Attachment A3                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


   [Confidential Treatment Requested] contract).

   Method for using an [Confidential Treatment Requested] for the detection of 
   [Confidential Treatment Requested] in the [Confidential Treatment Requested]
   field of a [Confidential Treatment Requested]. Priority: Application 
   [Confidential Treatment Requested] contract).

- -  Patent application filed for [Confidential Treatment Requested], comprising 
   one or more [Confidential Treatment Requested] used for [Confidential 
   Treatment Requested] contract).

- -  Method for detection of [Confidential Treatment Requested] in the 
   [Confidential Treatment Requested] field using [Confidential Treatment 
   Requested] for the [Confidential Treatment Requested] detection of several 
   [Confidential Treatment Requested] Ciba.

- -  [Confidential Treatment Requested] for [Confidential Treatment Requested] of 
   [Confidential Treatment Requested] substances [Confidential Treatment 
   Requested] Ciba).

Patents continued

- -  [Confidential Treatment Requested] (Ciba; in preparation)

- -  Principle design of [Confidential Treatment Requested] configuration for a 
   [Confidential Treatment Requested] system [Confidential Treatment Requested] 
   contract;  in preparation by [Confidential Treatment Requested].

Further know-how:

- -  The principle feasibility of [Confidential Treatment Requested] assays on 
   [Confidential Treatment Requested] areas [Confidential Treatment Requested] 
   has been demonstrated in model affinity [Confidential Treatment Requested] 
   and [Confidential Treatment Requested] assays [Confidential Treatment 
   Requested] of [Confidential Treatment Requested] with complementary, 
   [Confidential Treatment Requested] labeled strand).

- -  A first [Confidential Treatment Requested] system will be developed in the 
   module [Confidential Treatment Requested] for [Confidential Treatment 
   Requested] of the Ciba/CCD royalty project (Appendix A1).

- -  The [Confidential Treatment Requested] assay system was applied both on 
   [Confidential Treatment Requested] and on [Confidential Treatment 
   Requested].  From a [Confidential Treatment Requested] analysis of the 
   signals obtained at different concentrations, an 

<PAGE>


Attachment A3                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


   expected detection limit in the [Confidential Treatment Requested] range was 
   calculated.

- -  A detection limit of [Confidential Treatment Requested] binding to 
   [Confidential Treatment Requested] on a [Confidential Treatment Requested] 
   has been achieved.

- -  Immobilization of [Confidential Treatment Requested] acting as [Confidential 
   Treatment Requested] was performed by [Confidential Treatment Requested] 
   synthesis and using the [Confidential Treatment Requested] system, both on 
   [Confidential Treatment Requested] and on [Confidential Treatment Requested] 
   as [Confidential Treatment Requested]. With [Confidential Treatment 
   Requested] more than [Confidential Treatment Requested] cycles could be 
   performed on [Confidential Treatment Requested] without loss of performance.

- -  For model systems, a significant simplification of [Confidential Treatment 
   Requested] handling has been achieved using two approaches: A) [Confidential 
   Treatment Requested] system comprising [Confidential Treatment Requested] 
   and [Confidential Treatment Requested]  b) [Confidential Treatment 
   Requested] using [Confidential Treatment Requested] to generate 
   [Confidential Treatment Requested] as a [Confidential Treatment Requested].

- -  [Confidential Treatment Requested] Technology: A [Confidential Treatment 
   Requested] including [Confidential Treatment Requested] and [Confidential 
   Treatment Requested] techniques under clean room conditions, as well as 
   [Confidential Treatment Requested] and [Confidential Treatment Requested] 
   characterization methods have been established and applied to thorough 
   characterization.  First results are available in [Confidential Treatment 
   Requested] and [Confidential Treatment Requested] production.

Milestones (to be updated end of 1997)

Proposed                                      Completion             Responsible

Analysis and investigation of current         [Confidential 
[Confidential Treatment Requested]            Treatment
quantification assays on compatibility        Requested]
with [Confidential Treatment
Requested] technology

Design and adaption of [Confidential
Treatment Requested] model assays for
the recognition and quantification of
[Confidential Treatment Requested] on
[Confidential Treatment Requested].

Evaluation of sensitivity improvement
by combining [Confidential Treatment
Requested] and [Confidential Treatment
Requested] technology.

<PAGE>

Attachment A3                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


Development and evaluation of [Confidential   [Confidential 
Treatment Requested] concepts for high        Treatment     
throughput [Confidential Treatment            Requested]    
Requested]and [Confidential Treatment 
Requested] and [Confidential Treatment 
Requested] chemistry).

Minimum [Confidential Treatment Requested] 
for model assay determined

Relation between [Confidential Treatment 
Requested] and [Confidential Treatment 
Requested] between individual 
[Confidential Treatment Requested] 
investigated.

Establish required technologies for spacially 
[Confidential Treatment Requested].

Transfer [Confidential Treatment Requested]

Test of different assay formats for boundary assays.


Intellectual property from outside of the Royalty Project to be made available:

Ciba:         [Confidential Treatment Requested]

CCD:          [Confidential Treatment Requested]

Third party:  [Confidential Treatment Requested] technology
              (Chiron Corporation)

                                                      Above Amendment accepted:
                                                                 April 15, 1996

                                                       ____________  __________

MANAGEMENT

Project Management Meetings twice a year.

TECHNOLOGY TRANSFER CRITERIA  (Article 5.1)

Specifications will be re-examined at the end of [Confidential Treatment 
Requested].  Significant changes to the specs will be accepted through 
[Confidential Treatment Requested].  Only modest to small changes will be 
accepted in [Confidential Treatment Requested].

- -  A [Confidential Treatment Requested] system will have been set-up which is 
   capable of demonstrating throughput and assay performance under stable and 
   reproducible 

<PAGE>

Attachment A3                    Confidential                            Page
(Royalty Project Agreement)
       [Confidential Treatment Requested] for [Confidential Treatment Requested]


   conditions. It will include the [Confidential Treatment Requested] and 
   [Confidential Treatment Requested], a [Confidential Treatment 
   Requested] delivery system, the [Confidential Treatment Requested] system 
   for [Confidential Treatment Requested] and detection and experimental 
   control [Confidential Treatment Requested]. It is understood, that the main 
   purpose of the [Confidential Treatment Requested] will be to demonstrate 
   functionality and the main purpose of the [Confidential Treatment Requested] 
   to demonstrate assay performance. Costly and voluminous components, 
   evidently not suitable for CCD's commercial use will not be applied.

- -  Performance will be demonstrated using the assays and specification listed 
   below. [Confidential Treatment Requested] design experiments will be 
   applied in order to confirm the specs to be fulfilled.

- -  Documentation will be prepared to allow a skilled CCD technician to 
   reproduce the system and its performance in-house or to run a 
   [Confidential Treatment Requested] system physically transferred to CCD. 
   Documentation will include the accumulated experience about common failure 
   modes and reliability problems encountered during the research phase as 
   related to instrumentation and sensor chemistry.

PROTOTYPES/BOUNDARY ASSAYS      [Confidential Treatment Requested] Panel, 
                                [Confidential Treatment Requested] for 
                                [Confidential Treatment Requested] and 
                                [Confidential TreatmentRequested]

Specifications
- --------------

1.  Mode of operation                 [Confidential Treatment Requested] use

2.  Multiplexity                      Up to [Confidential Treatment Requested]
                                      per [Confidential Treatment Requested]

3.  Temperature                       [Confidential Treatment Requested]
                                      temperature incubations [Confidential 
                                      Treatment Requested] phases during total 
                                      incubation time)

4.  Sample size/OED                   [Confidential Treatment Requested]
                                      of extracted sample

5.  Time to first results             Up to [Confidential Treatment Requested] 
                                      (May require change)

6.  Samples                           [Confidential Treatment Requested] or 
                                      [Confidential Treatment Requested]

7.  Assay sensitivity                 [Confidential Treatment Requested] 
                                      Analyte (Input)

8.  Dynamic range                     Direct detection of up to [Confidential 
                                      Treatment Requested]

9.  Fluidics                          [Confidential Treatment Requested] sample 
                                      distribution

PROTOTYPES/BOUNDARY ASSAYS            [CONFIDENTIAL TREATMENT REQUESTED] (HIGH 
                                      SENSITIVITY PROTOTYPE) *


<PAGE>

Attachment A3                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]

                               PROTOTYPE)*


Specifications
- --------------

1.  Mode of operation        [Confidential Treatment Requested] use

2.  Multiplexity             [Confidential Treatment Requested] per[Confidential
                             Treatment Requested]

3.  Temperature              [Confidential Treatment Requested] temperature 
                             incubations

4.  Sample size/OED          [Confidential Treatment Requested] serum/plasma

5.  Time to first results    [Confidential Treatment Requested]

6.  Samples                  [Confidential Treatment Requested]

7.  Assay sensitivity        [Confidential Treatment Requested] molecules

8.  Dynamic range            [Confidential Treatment Requested] (with integrated
                             dilution)

9.  Fluidics                 [Confidential Treatment Requested]

*   [Confidential Treatment Requested] and [Confidential Treatment
    Requested] from prototype or marketed assays will be made available by
    Chiron Diagnostics whenever possible in support of the project milestones.
    In case of unavailability alternate assays will be negotiated.


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


Title:  [Confidential Treatment              Royalty Project for Ciba
Requested] Systems for                       Corning Diagnostics
[Confidential Treatment Requested]


                                             Status October 1995
- -------------------------------------------------------------------------------
Approved by:                                 Project Management:

                                             CCD: 
__________________ _________________
SVP, R&D, CCD      Head CRU, Ciba            Ciba:
15.12.95           15.12.95

Working basis agreed upon: Exclusive


OBJECTIVE

- -    Development of analytical systems for human diagnostics based on the
     combination of novel [Confidential Treatment Requested] elements with
     advanced [Confidential Treatment Requested] and [Confidential Treatment
     Requested] systems.

- -    Development of novel or modified functional components [Confidential
     Treatment Requested] host [Confidential Treatment Requested] for
     [Confidential Treatment Requested] and [Confidential Treatment Requested]
     for improved and patent Protected [Confidential Treatment Requested]
     systems for [Confidential Treatment Requested].


SCOPE OF APPLICATIONS/EXPECTED TECHNOLOGY TRANSFER DATES:

For [Confidential Treatment Requested] and    [Confidential Treatment Requested]
[Confidential Treatment Requested]            in [Confidential Treatment
                                              Requested]

For [Confidential Treatment Requested] and    [Confidential Treatment Requested]
[Confidential Treatment Requested]


[CONFIDENTIAL TREATMENT REQUESTED] MILESTONES

Refill [Confidential Treatment Requested]     [Confidential Treatment Requested]
each for                                      [Confidential Treatment Requested]

Medfield and Basel) and [Confidential         [Confidential Treatment Requested]
Treatment Requested] for Basel                [Confidential Treatment Requested]

Synthesize [Confidential Treatment            [Confidential Treatment Requested]
Requested]                                 


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]
      
             
                                              [Confidential Treatment Requested]

[Confidential Treatment Requested] testing    [Confidential Treatment Requested]
against specs                                 [Confidential Treatment Requested]

[Confidential Treatment Requested] testing    [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Evaluation of [Confidential Treatment         [Confidential Treatment Requested]
Requested] completed                          [Confidential Treatment Requested]

List of [Confidential Treatment Requested]    [Confidential Treatment Requested]
screened and documentation                    [Confidential Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
inventory returned to [Confidential           [Confidential Treatment Requested]
Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
inventory shipped to [Confidential            [Confidential Treatment Requested]
Treatment Requested] 

Narrow approach from [Confidential            [Confidential Treatment Requested]
Treatment Requested]                          [Confidential Treatment Requested]

Scale up of [Confidential Treatment           [Confidential Treatment Requested]
Requested] for evaluations Treatment          [Confidential Treatment Requested]
Requested]

Supply of [Confidential Treatment             [Confidential Treatment Requested]
Requested] for evaluation [Confidential       [Confidential Treatment Requested]
Treatment Requested]   

Scale up for [Confidential Treatment          [Confidential Treatment Requested]
Requested] and [Confidential Treatment        [Confidential Treatment Requested]
Requested]


[CONFIDENTIAL TREATMENT REQUESTED] MILESTONES

Report on [Confidential Treatment             [Confidential Treatment Requested]
Requested] study                              [Confidential Treatment Requested]

Report on study of [Confidential Treatment    [Confidential Treatment Requested]
Requested] using [Confidential Treatment      [Confidential Treatment Requested]
Requested]

Information and documentation for transfer    [Confidential Treatment Requested]
identified                                    [Confidential Treatment Requested]


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


[Confidential Treatment Requested] confirmed  [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

[Confidential Treatment Requested] study      [Confidential Treatment Requested]
[Confidential Treatment Requested]            [Confidential Treatment Requested]
wrapped up 

[Confidential Treatment Requested]            [Confidential Treatment Requested]
formulation optimized                         [Confidential Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
disclosure                                    [Confidential Treatment Requested]

Decision on continuation of [Confidential     [Confidential Treatment Requested]
Treatment Requested]                          [Confidential Treatment Requested]

Deliver [Confidential Treatment Requested]    [Confidential Treatment Requested]
with [Confidential Treatment Requested]       [Confidential Treatment Requested]

Scale up of [Confidential Treatment           [Confidential Treatment Requested]
Requested] and [Confidential Treatment        [Confidential Treatment Requested]
Requested] 


[CONFIDENTIAL TREATMENT REQUESTED] MILESTONES

Deliver [Confidential Treatment Requested]    [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Deliver [Confidential Treatment Requested]    [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Deliver [Confidential Treatment Requested]    [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Refill [Confidential Treatment Requested]     [Confidential Treatment Requested]
containing [Confidential Treatment            [Confidential Treatment Requested]
Requested] for Basel    

Refill [Confidential Treatment Requested]     [Confidential Treatment Requested]
containing [Confidential Treatment            [Confidential Treatment Requested]
Requested] for Medfield

Deliver [Confidential Treatment Requested]    [Confidential Treatment Requested]
to Medfield for [Confidential Treatment       [Confidential Treatment Requested]
Requested] testing

Extensive [Confidential Treatment             [Confidential Treatment Requested]
Requested] testing in [Confidential           [Confidential Treatment Requested]
Treatment Requested] 


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


Report on [Confidential Treatment             [Confidential Treatment Requested]
Requested] and [Confidential Treatment        [Confidential Treatment Requested]
Requested]

Refill [Confidential Treatment                [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

Comparative data on early response,           [Confidential Treatment Requested]
[Confidential Treatment Requested]            [Confidential Treatment Requested]

Decision on continuation of [Confidential     [Confidential Treatment Requested]
Treatment Requested]                          [Confidential Treatment Requested]

Conclude [Confidential Treatment              [Confidential Treatment Requested]
Requested] Support                            [Confidential Treatment Requested]

[Confidential Treatment Requested]
Milestones (Basel)

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] for research                       [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] for research                       [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
(research quantity)                           [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
(research quantity)                           [Confidential Treatment Requested]

Report on [Confidential Treatment             [Confidential Treatment Requested]
Requested] testing                            [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
(research quantity)                           [Confidential Treatment Requested]


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


Transfer [Confidential Treatment              [Confidential Treatment Requested]
Requested]                                    [Confidential Treatment Requested]

Report on [Confidential Treatment             [Confidential Treatment Requested]
Requested] testing                            [Confidential Treatment Requested]

Transfer [Confidential Treatment              [Confidential Treatment Requested]
Requested]                                    [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
development                                   [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested] ab)        [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
or [Confidential Treatment                    [Confidential Treatment Requested]
Requested] development

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested] kilo lab   [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Deliver [Confidential Treatment               [Confidential Treatment Requested]
Requested] with [Confidential Treatment       [Confidential Treatment Requested]
Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
or [Confidential Treatment Requested]         [Confidential Treatment Requested]
kilo lab

[Confidential Treatment Requested]
[Confidential Treatment Requested]
[Confidential Treatment Requested]


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


Intellectual property from outside of the Royalty Project to be made available:

Ciba:                         (to be confirmed)

CCD:                          (to be confirmed)

Third party:                  (to be confirmed)


MANAGEMENT

PROJECT MANAGEMENT MEETINGS TWICE A YEAR.

TECHNOLOGY TRANSFER CRITERIA  (ARTICLE 5.1)

1.  SPECIFICATIONS
- ------------------

All analytes:   According to [Confidential Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

[Confidential Treatment Requested]            [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]
                                              [Confidential Treatment Requested]

Response time:                                [Confidential Treatment Requested]


2.  PROTOCOLS:
- --------------

[Confidential Treatment Requested] performance testing in Basel will be done on
[Confidential Treatment Requested] system or the [Confidential Treatment
Requested] system in a [Confidential Treatment Requested] mode with
[Confidential Treatment Requested] sample solutions, QC materials from the
[Confidential Treatment Requested], according to [Confidential Treatment
Requested] protocol provided by CCD.  All tests to be performed at [Confidential
Treatment Requested] on equilibrated [Confidential Treatment Requested] samples
will be tested as a challenge but not to demonstrate the specifications.  The
initial response of the [Confidential Treatment Requested] will be investigated
and documented.


<PAGE>

Attachment A4                  Confidential                           Page
(Royalty Project Agreement)         [Confidential Treatment Requested]
                                    for[Confidential Treatment Requested]


3.  DOCUMENTATION:
- ------------------

Performance will be demonstrated using the assays and specifications listed
above.  Sufficient data will be compiled to allow an assessment of consistency.

Sufficient documentation will be prepared to allow a skilled CCD technician to
run the system and to reproduce the assays. Documentation will include the
accumulated experience about common failure modes and reliability problems
(including the stability of compounds, if tested) encountered during the
research phase as related to instrumentation and [Confidential Treatment
Requested] chemistry.

A materials list including the supplier, the purity and the available analysis
results will be provided for the critical materials of [Confidential Treatment
Requested] and [Confidential Treatment Requested] synthesis.


<PAGE>

Ciba-Geigy/Ciba Corning Royalty Projects                            3. Jan. 96
Attachment B


EXIT FEES AND ROYALTIES
(All numbers in MM CHF)

<TABLE>
<CAPTION>

<S>                                     <C>            <C>              <C>            <C>             <C>    

PROJECT OR APPLICATION                                 FEES                                            ROYALTY RATE *
- ----------------------                                 ----                                            --------------

                                        Refer to       Strategic        Technical       License        Exclusive
                                        Attachment     Failure Fee      Failure Fee     Maintenance    License

[Confidential Treatment Requested]         A4          [Confidential    [Confidential   [Confidential  [Confidential
Systems for [Confidential Treatment                    Treatment        Treatment       Treatment      Treatment
Requested]                                             Requested]       Requested]      Requested]     Requested]

[Confidential Treatment Requested] for     A1          [Confidential    [Confidential   [Confidential  [Confidential
                                                       Treatment        Treatment       Treatment      Treatment
                                                       Requested]       Requested]      Requested]     Requested]

[Confidential Treatment Requested] for     A2          [Confidential    [Confidential   [Confidential  [Confidential
                                                       Treatment        Treatment       Treatment      Treatment
                                                       Requested]       Requested]      Requested]     Requested]

[Confidential Treatment Requested] for     A3          [Confidential    [Confidential   [Confidential  [Confidential
                                                       Treatment        Treatment       Treatment      Treatment
                                                       Requested]       Requested]      Requested]     Requested]


*   For products that are within the scope of a patent issued in any Designated
    Country but that are sold in countries where patents are pending or are not
    filed, the royalty rate shall be [Confidential Treatment Requested] of the
    rate specified in the table.


Approved by:


______________________________                   _______________________________
SVP, R&D, CCD                                    Head CRU, Ciba


</TABLE>


<PAGE>

                                 EXHIBIT 11

                             CHIRON CORPORATION
                 STATEMENT OF COMPUTATION OF EARNINGS PER SHARE

<TABLE>
<CAPTION>
                                            Nine Months Ended Sept. 30,    Three Months Ended Sept. 30,
                                            ----------------------------   ----------------------------
                                                1996            1995           1996          1995
                                            ------------   -------------   ------------   -------------
<S>                                         <C>            <C>             <C>            <C>
EARNINGS PER SHARE
 Net income (loss) available for common
  shares and common stock equivalent
  shares deemed to have a dilutive effect   $ 39,876,000   $(530,056,000)  $ 11,778,000   $(145,107,000)
                                            ------------   -------------   ------------   -------------
                                            ------------   -------------   ------------   -------------

 Primary earnings (loss) per share          $       0.22   $       (3.30)  $       0.07   $       (0.90)
                                            ------------   -------------   ------------   -------------
                                            ------------   -------------   ------------   -------------

 Fully diluted earnings (loss) per share    $       0.22   $       (3.30)  $       0.07   $       (0.90)
                                            ------------   -------------   ------------   -------------
                                            ------------   -------------   ------------   -------------

Shares used in primary earnings (loss)
 per share computation:
   Weighted average common shares
    outstanding                              168,968,000     160,840,000    169,927,000     161,716,000
   Weighted average dilutive incremental
    common shares issuable from exercise
    of warrants                                  324,000              --        208,000              --
   Weighted average dilutive incremental
    common shares issuable under employee
    stock option programs                      8,000,000              --      5,713,000              --
                                            ------------   -------------   ------------   -------------
   Total common shares and common stock
    equivalent shares deemed to have a
    dilutive effect                          177,292,000     160,840,000    175,848,000     161,716,000
                                            ------------   -------------   ------------   -------------
                                            ------------   -------------   ------------   -------------

Shares used in fully dilutive earnings
 (loss) per share computation:
   Weighted average common shares
    outstanding                              168,968,000     160,840,000    169,927,000     161,716,000
   Weighted average dilutive incremental
    common shares issuable from exercise
    of warrants                                  326,000              --        208,000              --
   Weighted average dilutive incremental
    common shares issuable under employee
    stock option programs                      8,000,000              --      5,708,000              --
                                            ------------   -------------   ------------   -------------
   Total common shares and common stock
    equivalent shares deemed to have a
    dilutive effect                          177,294,000     160,840,000    175,843,000     161,716,000
                                            ------------   -------------   ------------   -------------
                                            ------------   -------------   ------------   -------------
</TABLE>


<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CHIRON
CORPORATION'S UNAUDITED CONSOLIDATED BALANCE SHEET DATED SEPTEMBER 30, 1996 AND
UNAUDITED CONSOLIDATED STATEMENT OF OPERATIONS FOR THE NINE MONTHS ENDED
SEPTEMBER 30, 1996 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-29-1996
<PERIOD-START>                             JAN-01-1996
<PERIOD-END>                               SEP-30-1996
<CASH>                                          53,967
<SECURITIES>                                    75,832<F1>
<RECEIVABLES>                                  340,358
<ALLOWANCES>                                         0
<INVENTORY>                                    186,786
<CURRENT-ASSETS>                               680,686
<PP&E>                                         744,358
<DEPRECIATION>                                 193,612
<TOTAL-ASSETS>                               1,668,256
<CURRENT-LIABILITIES>                          463,297
<BONDS>                                        420,044<F2>
                                0
                                          0
<COMMON>                                         1,700
<OTHER-SE>                                     745,737<F3>
<TOTAL-LIABILITY-AND-EQUITY>                 1,668,256
<SALES>                                        729,877
<TOTAL-REVENUES>                               943,035
<CGS>                                          316,973
<TOTAL-COSTS>                                  316,973
<OTHER-EXPENSES>                               562,392<F4>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                   0
<INCOME-PRETAX>                                 57,792<F5>
<INCOME-TAX>                                    17,916
<INCOME-CONTINUING>                             39,876
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    39,876
<EPS-PRIMARY>                                     0.22
<EPS-DILUTED>                                     0.22
<FN>
<F1>CONSISTS OF BOTH SHORT-TERM AND NON-CURRENT INVESTMENTS IN MARKETABLE DEBT
SECURITIES.
<F2>CONSISTS OF CONVERTIBLE SUBORDINATED DEBENTURES, CAPITAL LEASE OBLIGATIONS, AND
NOTES PAYABLE, NET OF CURRENT MATURITIES.
<F3>CONSISTS OF ADDITIONAL PAID-IN CAPITAL, ACCUMULATED DEFICIT, CUMULATIVE FOREIGN
CURRENCY TRANSLATION ADJUSTMENT AND UNREALIZED GAIN FROM INVESTMENTS.
<F4>CONSISTS OF RESEARCH AND DEVELOPMENT, SELLING, GENREAL AND ADMINISTRATIVE; AND
OTHER OPERATING EXPENSES.
<F5>INCLUDES A $12.2 MILLION GAIN FROM THE SALE OF A PARTNERSHIP INTEREST REFLECTED
IN OTHER EXPENSE, NET; AND $6.9 MILLION IN ROYALTIES RELATED TO PRIOR
PERIOD SALES RESULTING FROM A SETTLEMENT, REFLECTED IN EQUITY IN EARNINGS OF
UNCONSOLIDATED JOINT BUSINESSES.
</FN>
        

</TABLE>


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