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                                                                EXHIBIT 10.32.4
                                                                               
                                           
                                  THIRD AMENDMENT TO
                                 TERM LOAN AGREEMENT


     THIS THIRD AMENDMENT TO TERM LOAN AGREEMENT (this "Third Amendment") is
made and entered into as of the 21st day of February, 1997, by and between
GENZYME TRANSGENICS CORPORATION, a Massachusetts corporation having its
principal place of business at One Mountain Road, Framingham, Massachusetts 
01701 (the "Borrower"), and THE FIRST NATIONAL BANK OF BOSTON (the "Bank"), a
national banking association with its head office at 100 Federal Street, Boston,
Massachusetts 02110.

     WHEREAS, the Borrower and the Bank entered into a Term Loan Agreement dated
as of December 15, 1995, as amended by the First Amendment to Term Loan
Agreement dated as of March 29, 1996 and the Second Amendment to Term Loan
Agreement dated as of October 1, 1996 (as further amended and in effect from
time to time, the "Credit Agreement") pursuant to which the Bank extended credit
to the Borrower on the terms set forth therein;

     WHEREAS, the Bank and the Borrower have agreed to amend the Credit
Agreement as hereinafter set forth;

     NOW, THEREFORE, for good and valuable consideration the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

     1.   Definitions.  Capitalized terms used herein without definition have
the meanings ascribed to them in the Credit Agreement.

     2.   Amendment to Term Loan Agreement.  Effective as of December 30, 1996,
Section 7.2(a)(ix) of the Credit Agreement is hereby deleted in its entirety and
the following substituted in place thereof:

     "and (ix) Indebtedness of (a) TSI Corporation to Finova Technology Finance,
     Inc. (formerly Financing for Science International, Inc. ("Finova"))
     pursuant to the terms of the Master Equipment Lease Agreement dated as of
     September 27, 1994 by and between TSI Corporation and Financing for Science
     International, Inc., and of the Parent, Argus Research Laboratories, Inc.,
     TSI Mason Laboratories, Inc., TSI Redfield Laboratories, Inc., and TSI
     Washington Laboratories, Inc. to Finova pursuant to guaranties of such
     lease; and (b) the Parent to Transamerica Business Credit Corporation
     ("TBCC") pursuant to the terms of the Master Lease Agreement dated as of
     December 30, 1996 by and between TBCC and the Parent, and of TSI
     Corporation, BioDevelopment Laboratories, Inc., TSI Mason Laboratories,
     Inc., TSI Washington Laboratories, Inc., TSI Redfield Laboratories, Inc.,
     and Argus Research Laboratories, Inc. to TBCC pursuant to guaranties of
     such lease provided that the aggregate outstanding amount of all such
     Indebtedness shall not exceed $5,300,000."



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     3.   Ratification, etc. 

     Except as expressly amended hereby, the Credit Agreement, the other Loan
Documents and all documents, instruments and agreements related thereto are
hereby ratified and confirmed in all respects and shall continue in full force
and effect.  This Third Amendment and the Credit Agreement shall hereafter be
read and construed together as a single document, and all references in the
Credit Agreement or any related agreement or instrument to the Credit Agreement
shall hereafter refer to the Credit Agreement as amended by this Third
Amendment.  By executing this Third Amendment where indicated below, the
Guarantor hereby ratifies and confirms its guaranty of the Obligations pursuant
to the terms of the Guaranty, as amended, and acknowledges and consents to the
terms of this Third Amendment.

     4.   GOVERNING LAW.

     THIS THIRD AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE COMMONWEALTH OF MASSACHUSETTS AND SHALL TAKE EFFECT AS A SEALED
INSTRUMENT IN ACCORDANCE WITH SUCH LAWS.

     5.   Counterparts.  This Third Amendment may be executed in any number of
counterparts and by different parties hereto on separate counterparts, each of
which when so executed and delivered shall be an original, but all of which
counterparts taken together shall be deemed to constitute one and the same
instrument.  A complete set of counterparts shall be lodged with the Bank.

     6.   Effectiveness.  This Third Amendment shall become effective upon its
execution and delivery by the respective parties hereto.

     7.   Entire Agreement.  THE CREDIT AGREEMENT AS AMENDED REPRESENTS THE
FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF
PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.  THERE ARE
NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.
 

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     IN WITNESS WHEREOF, the undersigned have duly executed this Agreement under
seal as of the date first set forth above.

                              THE BORROWER:

                              GENZYME TRANSGENICS CORPORATION



                              By: /s/ John B. Green
                                  ------------------------
                                   Name:  John B. Green
                                   Title:  Vice President


                              Address of the Borrower:

                              One Mountain Road
                              Framingham, MA  01701
                              Tel:  (508) 872-8400
                              Fax:  (508) 872-0827


                              THE BANK:

                              THE FIRST NATIONAL BANK OF BOSTON



                              By: /s/ Elizabeth C. Everett
                                  ------------------------
                                   Name:  Elizabeth C. Everett
                                   Title:  Vice President

                                   Address:

                                   100 Federal Street
                                   Boston, MA 02110
                                   Tel:   617-434-2318
                                   Fax:  617-434-0819  


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ACCEPTED AND AGREED
TO BY:

The Guarantor:

GENZYME CORPORATION


By: /s/ Evan M. Lebson
------------------------------------
Title:  Vice President and Treasurer

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