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                                                                   EXHIBIT 10.42

                                 PROMISSORY NOTE

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED,
HYPOTHECATED OR OTHERWISE TRANSFERRED IN THE ABSENCE OF AN EFFECTIVE
REGISTRATION STATEMENT UNDER SAID ACT COVERING THE TRANSFER OF THE SECURITIES OR
AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT
REQUIRED.

$7,500,000                                             Sunnyvale, California
                                                              December 27, 1999
         FOR VALUE RECEIVED, the undersigned, Scios Inc., a Delaware corporation
(the "Borrower"), hereby promises to pay to the order of Chiron Corporation, a
Delaware corporation ("Chiron"), the principal sum of Seven Million Five Hundred
Thousand Dollars ($7,500,000), including interest as hereinafter provided. The
entire balance of outstanding principal and accrued and unpaid interest shall be
paid in full December 31, 2006, unless the loan has been earlier forgiven as
provided below.

         Interest shall accrue on the unpaid balance of the principal amount at
the rate of 8.5% compounded annually on the anniversary date of this Note and
calculated on the basis of a 360-day year and the number of days actually
elapsed with respect to the outstanding balance from time to time. Interest may
be paid from time to time as Scios elects or deferred until the principal is
paid in full. Accrued interest, together with all outstanding principal shall be
due and payable as set forth in the preceding paragraph.

         Principal, interest and all other amounts due under this Note shall be
payable by wire transfer in accordance with the wire transfer instructions
provided by Chiron, or by such other means as the holder of this Note may from
time to time designate in writing to the Borrower.

         The Borrower shall have the right, at any time, to prepay all or any
part of the outstanding principal amount without premium or penalty; provided,
however, that all payments hereunder shall first be applied to accrued and
unpaid interest and thereafter to principal.

         The Borrower hereby waives presentment, demand, notice, protest and
other demands and notices in connection with the delivery, acceptance or
enforcement of this Note.

         No delay or omission on the part of the holder of this Note in
exercising any right hereunder shall operate as a waiver of such right or of any
other right under this Note, and a waiver, delay or omission on any one occasion
shall not be construed as a bar to or waiver of any such right on any future
occasion.

         The Borrower hereby agrees to pay on demand all reasonable costs and
expenses, including, without limitation, attorneys' fees and legal expenses,
incurred or paid by the holder of this Note in enforcing this Note on default.

                                                                              1.
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         Upon receipt by the Borrower of evidence reasonably satisfactory to it
of the loss, theft, destruction or mutilation of this Note, and indemnity
satisfactory to the Borrower (in the case of loss, theft or destruction) or
cancellation of the Note (in the case of mutilation), the Borrower will make and
deliver to Chiron a new Note of like tenor and principal amount and dated as of
the date to which interest has been paid on the unpaid principal balance
hereunder.

         The following events are the Events of Default under this Note:

         (a)  Scios shall (i) voluntarily commence any proceeding or file any
              petition seeking relief under Title 11 of the United States Code
              or any other federal, state or foreign bankruptcy, insolvency,
              liquidation or similar law, (ii) consent to the institution of,
              or fail to contravene in a timely and appropriate manner, any
              such proceeding or the filing of any such petition, (ii) apply
              for or consent to the appointment of a receiver, trustee,
              custodian, or similar official for Scios or for a substantial
              part of its property or assets, (iv) file an answer admitting the
              material allegations of a petition filed against it in any such
              proceeding, (v) make a general assignment for the benefit of
              creditors, (vi) become unable, admit in writing its inability or
              fail generally, to pay its debts as they become due, or (vii)
              take corporate action for the purpose of effecting any of the
              foregoing;

         (b)  an involuntary proceeding shall be commenced or an involuntary
              petition shall be filed in a court of competent jurisdiction
              seeking (i) relief in respect of Scios' or of a substantial part
              of its property or assets under Title 11 of the United States
              Code or any other federal, state or foreign bankruptcy,
              insolvency, receivership or similar law, (ii) the appointment of
              a receiver, trustee, custodian, or similar official for Scios or
              for a substantial part of its property, or (iii) the winding-up
              or liquidation of Scios; and such proceeding or petition shall
              continue undismissed for sixty (60) days or an order or decree
              approving or ordering any of the foregoing shall continue
              unstayed and in effect for thirty (30) days; and

         (c)  this Note shall for any reason cease to be, or be asserted by
              Scios not to be, a legal, valid and binding obligation
              enforceable in accordance with its terms.

         Upon the happening of an Event of Default described in paragraph (a) or
(b) above, this Note shall automatically become due and payable, both as to
principal and interest, without presentment, demand, protest or other notice of
any kind, all of which are hereby expressly waived by Scios. Upon the happening
of an Event of Default described in paragraph (c) above, and at any time
thereafter during the continuance of such event, the holder of this Note may, by
written or telegraphic notice to Scios, declare the Note to be forthwith due and
payable, whereupon the principal of this Note, together with accrued interest
thereon and other liabilities of Scios accrued hereunder, shall become due and
payable both as to principal and interest, without presentment, demand, protest
or any other notice of any kind, all of which are hereby expressly waived by
Scios.

         The obligation of Scios represented by this Note shall be subordinate
to all other debt or obligations of Scios regardless of the date that such other
debt or obligation may be created. Chiron agrees to execute any document
reasonably requested by Scios or another creditor of Scios to evidence the
subordination of this Note to other obligations of Scios.

                                                                              2.
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         This Note shall be deemed to be under seal, and all rights and
obligations hereunder shall be governed by the laws of the State of California.

         This Note, including all outstanding principal and accrued and unpaid
interest, shall automatically be forgiven and Scios shall have no further
obligation of any kind to Chiron under this Note upon the granting of a New Drug
Approval by the United States Food and Drug Administration ) prior to December
31, 2006 authorizing the marketing in the United States of any FGF Product (as
defined in the FGF License and Technology Transfer Agreement).

AGREED:
SCIOS INC.                                CHIRON CORPORATION

         /s/ Richard B. Brewer                     /s/ James R. Sulat
By:                                       By:
   -----------------------------             -----------------------------------
         Richard B. Brewer                Name:    James R. Sulat
         President and CEO                Title:   Chief Financial Officer



                                                                              3.