January 20, 1999

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                                                                 Exhibit 10 (vi)

                [CHRYSALIS INTERNATIONAL CORPORATION LETTERHEAD]

                                January 20, 1999

Xx. Xxxx X. Xxxxxx
00 Xxxxxx Xxxxx
Xxxxxx, XX  18940

Dear Xx. Xxxxxx:

            Reference is hereby made to that certain letter agreement, dated May
29, 1996 (the "Letter Agreement"), between Chrysalis International Corporation
(the "Company") and you regarding the terms of your employment with the Company.
This letter hereby amends the Letter Agreement as follows:

            Section 4(b)(1) of the Letter Agreement is hereby amended and
restated to read as follows:

            "(1)  biweekly severance payments at the rate of your base salary at
                  the time of termination for a period of 12 months regardless
                  of your employment status; provided however, that if the
                  merger contemplated by the Agreement and Plan of Merger, dated
                  November 18, 1998, among the Company, Phoenix International
                  Life Sciences Inc. and Phoenix Merger Sub. Corp. is
                  consummated, a payment equal to the aggregate of one year's
                  base salary in effect at the time of termination;"

            Section 4(b)(4) of the Letter Agreement is hereby amended and
restated to read as follows:

            (4)   Amendments to all stock options granted to you and that have
                  not expired or terminated by their terms prior to the date
                  your employment is terminated by the Company to provide that
                  each such stock option shall be exercisable for a period
                  commencing on the date of termination of employment by the
                  Company and ending on the earlier to occur of (a) 18 months
                  after the date of termination, or (b) (i) the tenth
                  anniversary of the date of grant of such stock option

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Xx. Xxxx X. Xxxxxx
January 20, 1999
Page 2

                  if such stock option was not granted under the Company's 1988
                  Stock Option Plan or was not amended by the Compensation
                  Committee of the Company's Board of Directors on November 15,
                  1998, or (ii) the date occurring ten years and two months
                  after the date of grant of such stock option if such stock
                  option was granted under the Company's 1988 Stock Option Plan
                  and such option was amended by the Compensation Committee of
                  the Company's Board of Directors on November 15, 1998.

            Please acknowledge your agreement to the terms of this letter by
executing this letter in the space indicated below.

                                        Sincerely,


                                        /s/  Xxxx X. Xxxxxxx
                                        Xxxx X. Xxxxxxx
                                        President

AGREED TO AND ACCEPTED

/s/ Xxxx X. Xxxxxx
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Xxxx X. Xxxxxx