UNITED STATES
                SECURITIES AND EXCHANGE COMMISSION
                      Washington, D.C. 20549

                          SCHEDULE 13D

            Under the Securities Exchange Act of 1934
                        (Amendment No. 2)

                      Synbiotics Corporation
                                                                 
                         (Name of Issuer)

                     Common Stock, no par value
                                                                 
                   (Title of Class of Securities)

                            87156610
                                                                 
                         (CUSIP Number)

      Roger A. Keller, 7733 Forsyth Blvd., St. Louis, MO 63105
                         (314) 854-5244
                                                                 
             (Name, Address and Telephone No. of Person 
          Authorized to Receive Notices and Communications)

                        November 14, 1996
                                                                 
    (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G
to report the acquisition which is the subject of this Schedule 13D,
and is filing this schedule because of Rule 13d-1(b)(3) or (4), check
the following box / /.

Note: Six copies of this statement, including all exhibits, should be
filed with the Commission.  See Rule 13d-1(a) for other parties to
whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject
class of securities, and for any subsequent amendment containing
information which would alter disclosures provided in a prior cover
page.

The information required on the remainder of this cover page shall
not be deemed to be "filed" for the purpose of Section 18 of the
Securities Exchange Act of 1934 ("Act") or otherwise subject to the
liabilities of that section of the Act but shall be subject to all
other provisions of the Act (however, see the Notes).




                          SCHEDULE 13D

CUSIP No. 87156610                                     Page 2 of 4
                                                                  
1.  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
    Mallinckrodt Inc.: 36-1263901
                                                                  
2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a) / /
                                                         (b) / /
    n/a
                                                                  

3.  SEC USE ONLY

                                                                  
4.  SOURCE OF FUNDS
    00
                                                                  
5.  CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS
    IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)
    n/a                                                      / /
                                                                  
6.  CITIZENSHIP OR PLACE OF ORGANIZATION
    New York
                                                                  
               7.  SOLE VOTING POWER
  NUMBER OF        539,639
   SHARES                                                         
 BENEFICIALLY  8.  SHARED VOTING POWER
   OWNED BY        n/a
     EACH                                                         
  REPORTING    9.  SOLE DISPOSITIVE POWER
    PERSON         539,639
     WITH                                                         
               10.  SHARED DISPOSITIVE POWER
                    n/a
                                                                  
11.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
     539,639
                                                                  
12.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
     CERTAIN SHARES                                          / /
     n/a
                                                                  
13.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
     7.3%
                                                                  
14.  TYPE OF REPORTING PERSON
     CO
                                                                  




CUSIP No. 87156610                                    Page 3 of 4

Item 1.  Security and Issuer.
- ------------------------------

     This statement relates to the Common Stock, no par value (the
"Common Stock"), of Synbiotics Corporation, a California corporation
(the "Issuer"), whose executive offices are located at 11011 Via
Frontera Drive, San Diego, CA 92127.

Item 2.  Identity and Background.
- ----------------------------------

     Mallinckrodt Inc. is a New York corporation ("Mallinckrodt") whose
principal business is the production and sale of specialty
pharmaceutical and highly selected specialty industrial chemicals; the
production and sale of human health products in the fields of
cardiology, radiology, anesthesiology, nuclear medicine and critical
care; and the production and sale of animal health and nutrition
products.  Mallinckrodt's principal office is located at 7733 Forsyth
Boulevard, St. Louis, Missouri 63105.  

     During the last five years, neither Mallinckrodt nor any of its
executive officers, directors or controlling persons has been convicted
in a criminal proceeding (excluding traffic violations or similar
misdemeanors).

     During the last five years, neither Mallinckrodt nor any of its
executive officers, directors or controlling persons has been and is not
now (a) subject to a judgment, decree or final order enjoining future
violations of, or prohibiting or mandating activities subject to,
federal or state securities laws, or (b) a party to a civil proceeding
of a judicial or administrative body of competent jurisdiction finding
any violation with respect to such laws.

Item 3.  Source and Amount of Funds or Other Consideration.
- ------------------------------------------------------------

     Mallinckrodt received 80,833 shares of the Issuer's Common Stock
in connection with the dissolution of H&Q Life Science Ventures, a
California limited partnership (the "Partnership") which was formed to
invest in securities of companies engaged in life science industries in
the start-up and development phases.  Mallinckrodt was a limited partner
of the Partnership.  The distribution of shares by the Partnership to
Mallinckrodt occurred on November 14, 1996.

Item 4.  Purpose of Transaction.
- ---------------------------------

     See response to Item 3 above.  Mallinckrodt will consider disposing
of some or all of the Issuer's Common Stock, depending on conditions in
the open market.  As previously reported in Mallinckrodt's filing on

 

CUSIP No. 87516610                                     Page 4 of 4

Schedule 13D, Amendment No. 1, filed with the Securities and Exchange
Commission on December 14, 1992, Mallinckrodt has agreed to limitations
on its right to sell the 458,806 shares of Common Stock owned by
Mallinckrodt prior to the within described acquisition of additional
shares.  Such limitations do not apply to the recently-acquired shares.

Item 5.Interest in Securities of the Issuer.
- -----------------------------------------------

(a) Mallinckrodt beneficially owns an aggregate of 539,639 shares of
Common Stock of the Issuer, representing approximately 7.3% of the
issued and outstanding shares of the Common Stock.

(b) Mallinckrodt has voting and dispositive power with respect to
539,639 shares of the Common Stock.

(c) Except as set forth in item 3, Mallinckrodt has not engaged in any
transactions during the past sixty (60) days with respect to shares of
the Common Stock.

(d) Mallinckrodt has the right to receive dividends from or the proceeds
from the sale of the Common Stock.

(e) Not applicable.

Item 6.  Contracts, Arrangements, Understandings or
         Relationships with Respect to Securities of the Issuer
- ----------------------------------------------------------------

     No change from information contained in Mallinckrodt's prior
filings on Schedule 13D with respect to the Common Stock.

Item 7.  Material to be Filed as Exhibits.
- --------------------------------------------

     Not applicable.
                            Signature
                            ----------
     After reasonable inquiry and to the best of my knowledge and
belief, the undersigned certifies that the information set forth in this
statement is true, complete and correct.

Date:  February 17, 1997

            MALLINCKRODT INC., a New York corporation

            By: /s/ Roger A. Keller
                -------------------------------
            Name: Roger A. Keller
            Title: Vice President, Secretary & General Counsel