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                                                                 Exhibit 10.16

            THIRD AMENDMENT TO AMENDED AND RESTATED LOAN AND SECURITY
                     AGREEMENT DATED MARCH 2, 1999 BETWEEN
               BROWN BROTHERS HARRIMAN & CO., AS AGENT FOR ITSELF
                 AND FLEET NATIONAL BANK F/K/A BANKBOSTON, N.A.
                                       AND
                             HARVARD APPARATUS, INC.

         This Third Amendment to Amended and Restated Loan and Security
Agreement (hereinafter, the "Amendment") is made as of this __ day of October,
2000 by and between HARVARD APPARATUS, INC.,a Massachusetts corporation with its
principal executive office at 84 October Hill Road, Holliston, Massachusetts
(hereinafter, the Borrower") and BROWN BROTHERS HARRIMAN & CO. (the "Agent"), as
agent for itself and FLEET NATIONAL BANK f/k/a BankBoston, N.A., (hereinafter,
the "Lenders"), in consideration of the mutual covenants contained herein and
the benefits to be derived herefrom. Unless otherwise specified herein, all
capitalized terms shall have the same meaning as set forth in the Loan Agreement
(as defined hereinbelow).

                              W I T N E S S E T H:

         WHEREAS, the Borrower executed and delivered to the Agent a certain
Amended and Restated Loan and Security Agreement dated March 2, 1999, as amended
by Amendments dated as of December 31, 1999 and July 14, 2000 (hereinbefore and
hereinafter, as amended, the "Loan Agreement") pursuant to which, among other
things, the Lenders extended in favor of the Borrower a Revolving Credit in the
original maximum principal amount of $3,750,000.00, Term Notes in the aggregate
original principal amount of $2,100,000.00, and supplemental Term Notes in the
aggregate original principal amount of $2,000,00.00; and

         WHEREAS, the Borrower has requested that the Lenders (i) amend the Loan
Agreement to increase the maximum principal amount available under the Revolving
Credit from $3,750,000.00 to $4,125,000.00, and (ii)otherwise amend the Loan
Agreement as provided for herein; and

         WHEREAS, the Lenders have indicated their willingness to do so, BUT
ONLY on the terms and conditions contained in this Amendment; and

         WHEREAS, the Borrower has determined that this Amendment is in the
Borrower's best interest.

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

         1. The Borrower hereby certifies to the Lenders that, to the best of
the Borrower's knowledge and belief after due inquiry, the representations and
warranties contained in the Loan Agreement, as

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modified by this Amendment, are true as of the date hereof and that no Event of
Default under the Loan Agreement or any document executed in connection
therewith has occurred and is continuing.

         2. The Borrower acknowledges and agrees that the Borrower has no
offsets, defenses, claims or counterclaims against the Lenders with respect to
the Loan Agreement, this Amendment or any other document, instrument or
agreement executed and delivered by Borrower to any of the Lenders in connection
therewith and, to the extent that the Borrower has any such offsets, defenses,
claims or counterclaims, the Borrower hereby affirmatively WAIVES any such
offsets, defenses, claims or counterclaims and specifically RELEASES the Lenders
for any such liability on account thereof.

         3. Section 1-1(b)(i)(A)of the Loan Agreement is hereby amended by
deleting same in its entirety and substituting the following therefor:

                  "(A) Four Million One Hundred Twenty Five Thousand Dollars
                  ($4,125,000.00),"

         4. Article 4 of the Loan Agreement is hereby amended by deleting the
definition of "Commitment" set forth therein in its entirety and substituting
the following therefor:

                  ""Commitment": $8,225,000.00 plus Acquisition Loans."

         5. Section 7-8 of the Loan Agreement is hereby amended, effective as of
December 31, 1999, by deleting same in its entirety and substituting the
following therefor:

                  "7-8. PROFITS. The Borrower's consolidated net income
                  (exclusive of imputed interest on warrants and options) after
                  taxes shall be no less than (a) $1,000,000.00 in fiscal year
                  1999, (b) $1,200,000.00 in fiscal year 2000, and (c)
                  $1,400,000.00 in fiscal year 2001, to be tested upon the
                  earlier of (i) completion of the Borrower's annual audited
                  financial statements, or (ii) on hundred (100) days following
                  the end of the Borrower's fiscal year."

         6. This Amendment shall become effective as of the date hereof upon
the satisfaction of the following conditions:

                  (a)      LOAN DOCUMENTS. The Agent shall have received this
                           Amendment executed and delivered by a duly authorized
                           officer of the Borrower, with a counterpart for each
                           Lender.


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                  (b)      CORPORATE PROCEEDINGS OF BORROWER. The Agent shall
                           have received, with a counterpart for each Lender,
                           resolutions of the Borrower authorizing the
                           execution, delivery and performance of this Amendment
                           and all transactions contemplated hereby.

                  (c)      OFFICER'S CERTIFICATE. The Borrower shall have
                           delivered to the Agent an Officer's Certificate in
                           the form of Exhibit A hereto.

                  (e)      AMENDMENT TO MASTER NOTES. The Borrower shall have
                           delivered to the Agent and the Lender an Amendment to
                           each Master Note in form and substance satisfactory
                           to the Agent to reflect the terms of this Amendment.

                  (f)      ADDITIONAL ASSURANCES. The Borrower shall have
                           delivered to the Agent such additional documents,
                           instruments or agreements as the Agent may reasonably
                           require in order to more fully confirm, vest and/or
                           perfect the Agent's first perfected security interest
                           in and to all collateral now or previously granted to
                           the Agent more securely in the Agent and the Lenders
                           and to otherwise give effect to the terms of this
                           Amendment.

                  (g)      FEES. The Borrower shall have paid to the Agent all
                           fees and expenses due by the Borrower to the Agent
                           and each Lender as well as all fees and expenses of
                           the Agent's and/or any Lender's attorneys.

         7. This Amendment and all other documents, instruments or agreements
executed in connection herewith incorporate all discussions and negotiations
between the Borrower and the Lenders, either expressed or implied, concerning
the matters included herein, any statute, custom, or usage to the contrary
notwithstanding. No such discussions or negotiations shall limit, modify or
otherwise affect the provisions hereof. No modification, amendment, or waiver of
any provision of this Amendment or the Loan Agreement or any provision under any
other agreement, document or instrument between the Borrower and the Lenders
shall be effective unless executed in writing by the party to be charged with
such modification, amendment or waiver, and if such party be a Lender, then by a
duly authorized officer thereof.


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         8. Except as specifically modified herein, the Loan Agreement shall
remain in full force and effect as originally written and the Borrower hereby
ratifies and confirms all terms and conditions contained therein and further
ratifies and reaffirms all representations and warranties made therein as of the
date hereof.

         9. This 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.

         10. This Amendment may be executed in one or more counterparts, each of
which shall be deemed to be an original and all of which, when taken together,
shall be deemed to be one and the same instrument.

         IN WITNESS WHEREOF, the parties have hereunto set their hands and seals
as of the date first written above.

                                                   HARVARD APPARATUS, INC.

                                            By: /s/ James Warren
                                                -------------------------------
                                            Title: CFO
                                                -------------------------------
ACKNOWLEDGED AND AGREED:

per pro BROWN BROTHERS HARRIMAN & CO.,
as Agent and as a Lender

By:
    --------------------------
Name: TIMOTHY T. TELMAN
      ------------------------
Title: VICE PRESIDENT
       -----------------------
FLEET NATIONAL BANK f/k/a
BankBoston, N.A.,
as a Lender

By:____________________________

Name:__________________________

Title:_________________________