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                                                                      Exhibit 10



March 24, 2000

[Name and address]

Dear [Name]:

         This letter confirms discussions with you concerning the decision of
Dexter Corporation ("Company") to pursue a number of strategic alternatives for
the Company going forward. It also describes the agreement between you, the
Company, and its subsidiary, Life Technologies, Inc. ("LTI"), as to the terms of
your continued employment with LTI and the benefits you have the opportunity to
receive from LTI.

         Because the Company and LTI believe that your leadership, expertise and
support of the business are valuable assets, we have selected you to receive a
retention payment under the terms and conditions set forth below. We considered
your continued, visible demonstration of these strong leadership qualities an
important factor in our assessment of your performance and, likewise, in our
assessment of your eligibility for the retention payment.

         In consideration of your agreement to continue working in your present
position and at your current level of performance in accordance with the
provisions set forth below, the Company and LTI hereby agree to the following
arrangements:

1.   You shall be entitled to receive a lump sum payment from LTI of $_____
     ("Retention Payment") less applicable withholding on the first to occur of
     one of the following: (a) you are involuntarily terminated, without cause,
     by LTI prior to February 28, 2001 and prior to the completion of a
     Strategic Transaction (as defined below); (b) a Strategic Transaction is
     completed by February 28, 2001 and you do not receive an offer of
     employment within ten days following the completion of a Strategic
     Transaction for a position going forward that is comparable to your current
     position with LTI, (i.e. one with similar duties and responsibilities and
     substantially similar compensation) immediately before the completion of a
     Strategic Transaction; (c) you are involuntarily terminated, without cause,
     within ninety days after the completion of a Strategic Transaction provided
     that such Strategic Transaction occurs prior to February 28, 2001; (d) you
     continue as an active employee for 90 days after the completion of a
     Strategic Transaction that has been completed by February 28, 2001, or (e)
     you are still employed as of February 28, 2001 and, as of that date, a
     Strategic Transaction has not been completed. Payment of the Retention
     Payment shall be made within ten days after you have returned an executed
     copy of the Release Agreement attached hereto to LTI, unless you have
     revoked your acceptance of the Release Agreement in accordance with its
     terms. For the purposes hereof, the term "cause" shall mean (i) an
     intentional act of fraud, embezzlement or theft in connection with your
     duties or in the course of your employment; (ii) intentional wrongful
     damage to property of the Company, LTI, or Buyer; (iii) intentional
     wrongful disclosure of secret processes or confidential information of the
     Company, LTI, or Buyer; (iv) acts of gross negligence or willful misconduct
     or (v) conviction of a felony, or conviction of another crime involving
     moral

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     turpitude. Neither the Company, LTI, nor any of their Affiliates shall take
     any adverse action against you relating to your employment or compensation
     as a result of your exercising your rights under this Letter Agreement.

2.   For purposes hereof, "Strategic Transaction" shall mean:

     (i) Any acquisition or series of acquisitions, by any individual,
     entity or group of beneficial ownership (within the meaning of Rule 13d-3
     under the Securities Exchange Act of 1934 (the "Exchange Act")) of 20% or
     more of the then outstanding shares of common stock of the Company or LTI;
     or

     (ii) Individuals who, as of the date of this agreement, constitute the
     Board of Directors of the Company or LTI (in either case, the "Incumbent
     Board") cease for any reason to constitute at least a majority of the Board
     of Directors of the Company or LTI, respectively, provided that any
     individual becoming a director subsequent to the date of this agreement,
     whose election, or nomination for election, by the stockholders of the
     Company or LTI, respectively, was approved by a vote of at least a majority
     of the directors then comprising the respective Incumbent Board, shall be
     considered as though such individual were a member of the respective
     Incumbent Board, but excluding, for this purpose, any such individual whose
     initial assumption of office is in connection with an actual or threatened
     election contest (as such terms are used in Rule 14a-11 of the Regulation
     14A promulgated under the Exchange Act) relating to the election of
     directors of the Company or LTI, respectively; or

     (iii) Approval by the stockholders of a complete liquidation or
     dissolution of the Company or LTI, or of the sale or other disposition of
     all or substantially all of the assets of the Company or LTI, or of a
     reorganization, merger or consolidation of the Company or LTI.

3.   Your entitlement to receive the Retention Payment described herein is
     separate and independent from your eligibility and entitlement to receive
     benefits under the Dexter Corporation Special Severance Program, LTI's
     Separation/Termination Policy (PP-121), any stock option plan, any pension
     or retirement plan, or under any other applicable severance program or
     agreement for which you may be eligible and which is attached hereto in
     Exhibit A. Your eligibility for, and entitlement to receive, such benefits
     will be determined in accordance with the terms and conditions of the
     applicable plan or agreement.

4.   All regularly scheduled performance and salary reviews by the Company or
     LTI, which fall on a date prior to your last day of work, will be
     conducted, and salary adjustments shall be made in accordance with standard
     practice.

The foregoing payments and benefits are contingent upon your execution of the
Release Agreement attached to this letter agreement. You may execute the Release
Agreement only after you have satisfied one of the conditions - (a), (b), (c),
(d), or (e) -described in paragraph 1, above. If you execute the Release
Agreement prior to satisfying any of these conditions, you will be required to
re-execute the Release Agreement after you have satisfied one of the conditions
in order to be eligible to receive the Retention Payment. As described more
fully in the Release Agreement, you may revoke your acceptance of the Release
Agreement by notifying LTI in writing of your decision to revoke in seven (7)
days of the date on which you delivered an executed copy of the Release

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Agreement to LTI, in which case the Release Agreement and this letter agreement
will be null and void and you will not be entitled to the Retention Payment.

Please indicate your understanding and acceptance of these terms and conditions
by signing in the space provided.

                               DEXTER CORPORATION


                                      By: /s/ Lawrence D. McClure
-----------------------------------       -------------------------------
[Name]                                    Lawrence D. McClure
                                          Vice President, Human Resources

-----------------------------------       -------------------------------
Date                                                   Date



                                    LIFE TECHNOLOGIES, INC.


                                    By: /s/ V.W. Brinkerhoff, III
                                        ---------------------------------
                                          V.W. Brinkerhoff, III
                                          Vice President of Human Resources

                                        ---------------------------------
                                                       Date

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                                                                      Exhibit 10

                                RELEASE AGREEMENT

          This Release Agreement ("Agreement"), dated as of March 24, 2000, is
among the Dexter Corporation ("Dexter"), Life Technologies, Inc. ("LTI") and
("you").

                                   WITNESSETH

     WHEREAS, pursuant to a letter dated March 24, 2000 from Dexter and LTI
to you ("Letter Agreement"), which is hereby incorporated by reference, Dexter
and LTI agreed to provide you with certain benefits (collectively, the
"Benefits") under certain circumstances in connection with Dexter's pursuit or
completion of a Strategic Transaction (as defined in the Letter Agreement).

     WHEREAS, the agreement of Dexter and LTI to provide the Benefits is
expressly contingent upon your entering into this Agreement; and

     WHEREAS, you desire to enter into this Agreement;

     NOW, THEREFORE, the parties agree as follows:

1.       Release. In exchange for receipt of the Benefits, you and all persons
         -------
     acting on your behalf release Dexter, LTI, and all of their affiliated
     companies, business and operating units together with all their respective
     officers, agents, representatives, shareholders, employees, successors,
     predecessors, and assigns from any and all claims, actions, charges, causes
     of action, rights, demands, damages of whatever nature, known or unknown,
     existing as of the date you sign this Agreement arising out of or relating
     to your employment or the separation of your employment from Dexter or LTI,
     including but not limited to, any claims that arise under the common law of
     contracts, breach of any implied or express employment contract or
     covenant, tort, public policy, wrongful termination, defamation, or any
     claim of discrimination based on race, gender, age, marital status,
     religion, national origin, handicap, disability, veteran's status, sexual
     preference, or retaliation (including the federal Age Discrimination in
     Employment Act of 1967, Title VII of the Civil Rights Act of 1964, the
     Civil Rights Act of 1991, the Americans with Disabilities Act of 1990, the
     Employment Retirement Income Security Act of 1974, and the Family Medical
     Leave Act of 1993, each as amended, or any other federal, state or local
     law, regulation or ordinance; provided, however, that this release does not
     apply to any claims, actions, charges, causes of action, rights, demands,
     damages of whatever nature, known or unknown, existing by virtue of (i) any
     severance program, severance policy or agreement referenced in the Letter
     Agreement or attached in an Exhibit to the Letter Agreement, or (ii) any
     stock option plan and/or related agreement, or (iii) any pension or
     retirement plan benefits arising out of your employment.

     By signing this Agreement, you agree that you will not seek or be entitled
     to any personal recovery in any claim, charge, action or proceeding
     whatsoever against Dexter or LTI, in any forum, arising out of or relating
     to any of the matters released hereby.

     You agree that you are signing this Agreement knowingly and voluntarily,
     that you have not been coerced or threatened into signing it, and that you
     have not been promised anything else in exchange for signing it. You

                                      20
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     further agree that this Agreement was delivered to you on _________, 2000
     and that you have had at least 21 days to consider this Agreement, although
     you may voluntarily choose to sign it in less time. Dexter and LTI advise
     you to consult with an attorney, if you desire, before signing this
     Agreement. You may revoke this Agreement by notifying LTI (through its Vice
     President of Human Resources) in writing of such decision within seven (7)
     days after you have delivered a signed copy of the Agreement to LTI, in
     which case this Agreement and the Letter Agreement shall be null and void.
     If you do not notify LTI of your intent to revoke this Agreement within
     such seven (7) day period, it shall become binding and enforceable on the
     eighth (8) day following the day which you have delivered a signed copy of
     this Agreement to LTI.

2.   Non-disclosure Agreement. In exchange for the receipt of the Benefits, you
     ------------------------
     further agree that you shall not use or disclose to any person or entity
     any proprietary or confidential information acquired by you from Dexter or
     LTI, except for use or disclosure of such information in your employment by
     Dexter or LTI in a manner consistent with the obligations arising from such
     employment. There shall be no time limitation with respect to the
     obligations under this Section 2.

3.   Miscellaneous.
     --------------

     3.1 Entire Agreement. This Agreement, the Letter Agreement, and any
         ----------------
     Exhibits thereto, contain all of the terms, promises, representations, and
     understandings made between the parties and supersede any previous
     representations, understandings, or agreements as relates to the subject
     matter herein.

     3.2 Amendments. This Agreement may be amended only by a writing executed by
         ----------
     Dexter, LTI, and you.


     3.3 Governing Law. This Agreement shall in all respects be governed by and
         -------------
     construed in accordance with the laws of the State of Connecticut without
     reference to its conflict of law rules.

     3.4 Counterparts. This Agreement may be executed in any number of
         ------------
     counterparts, each of which shall be deemed to be an original, and all of
     which together will constitute one and the same instrument.

     3.5 Waivers. Any waiver by any party of any violation or, breach of or
         -------
     default under, any of the provisions of this Agreement by the other party
     shall not be construed as, or constitute, a continuing waiver of such
     provision, or waiver or any other violation of, breach of or default under
     any provision of this Agreement.

     3.6 You acknowledge and agree that it is our mutual desire and intent that
     the provisions of this Agreement shall be enforced to the fullest extent
     permissible under the laws and public policies applied in each jurisdiction
     in which enforcement is sought. In the event that any one or more of the
     provisions or parts thereof of this Agreement shall be held to be invalid,
     illegal, or unenforceable, the validity, legality and enforceability of the
     remainder of this Agreement shall not in any way be affected or impaired
     thereby. Moreover, if any one or more of the provisions or parts thereof
     contained in this Agreement is held to be excessively broad as to duration,
     scope, activity or subject, such

                                      21
<PAGE>

     provisions shall be construed by limiting and reducing them so as to be
     enforceable to the maximum extent allowed by applicable law.

     Nothing in this Agreement will waive or otherwise release you from any
     obligations you may have to Dexter or LTI, including without limitation,
     the [name of agreement] between you and LTI that you signed on [date].

     You acknowledge that the Benefits represent a substantial benefit to you to
     which you would not have been entitled had you not entered into this
     Agreement.

IN WITNESS WHEREOF, this Agreement has been duly signed as of the date first
above written.

DEXTER CORPORATION


By:/s/ Lawrence D. McClure
   ----------------------------------                             --------------
     Lawrence D. McClure                                              Date
     Vice President, Human Resources


LIFE TECHNOLOGIES, INC.

By:/s/ V.W. Brinkerhoff III
   ----------------------------------                             --------------
     V.W. Brinkerhoff III                                             Date
     Vice President of Human Resources


-------------------------------------                             --------------
Employee Signature                                                    Date

To be executed by Employee and returned to LTI's Vice President of Human
Resources upon execution of the Letter Agreement and again at a date no earlier
than the date on which Employee becomes entitled to receive the Retention
Payment in accordance with paragraph 1 of the Letter Agreement.

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