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                                                                   Exhibit 99.14

                      [LETTERHEAD OF GOLDMAN, SACHS & CO.]

PERSONAL AND CONFIDENTIAL
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December 16, 1996

Board of Directors
Tylan General, Inc.
15330 Avenue of Science
San Diego, California 92128

Gentlemen:

You have requested our opinion as to the fairness to the holders of the
outstanding shares of Common Stock, par value $.001 per share (the "Shares"),
of Tylan General, Inc. (the "Company") of the $16.00 per Share in cash proposed
to be paid by Millipore Corporation ("Millipore") in the Tender Offer and the
Merger (as defined below) pursuant to the Agreement and Plan of Merger dated as
of December 16, 1996 among Millipore, MCTG Acquisition Corp. ("MCTG"), a
wholly-owned subsidiary of Millipore, and the Company (the "Agreement").

The Agreement provides for a tender offer for all of the Shares (the "Tender
Offer") pursuant to which MCTG will pay $16.00 per Share in cash for each Share
accepted. The Agreement further provides that following completion of the
Tender Offer, MCTG will be merged into the Company (the "Merger") and each
outstanding Share (other than Shares already owned by Millipore) will be
converted into the right to receive $16.00 in cash.

Goldman, Sachs & Co., as part of its investment banking business, is
continually engaged in the valuation of businesses and their securities in
connection with mergers and acquisitions, negotiated underwritings, competitive
biddings, secondary distributions of listed and unlisted securities, private
placements and valuations for estate, corporate and other purposes. We are
familiar with the Company having acted as its financial advisor in connection
with, and having participated in certain negotiations leading to, the Agreement.

In connection with this opinion, we have reviewed, among other things, the
Agreement; audited financial statements and other financial data of the Company
for the fiscal years ended October 31, 1993 and October 31, 1994; Annual
Reports to Stockholders and Annual Reports on Form 10-K of the Company for the
fiscal year ended October 31, 1995; certain interim reports to stockholders and
Quarterly Reports on Form 10-Q; certain other communications from the Company
to its stockholders; and certain internal financial analyses and forecasts for
the Company prepared by its management. We also have held discussions with
members of the senior management of the Company regarding its past and current
business operations, financial condition and future prospects. In addition, we
have reviewed the reported price and trading activity for the Shares, compared
certain financial and stock market information for the Company with similar
information for certain other companies the securities of which are publicly
traded, reviewed the financial terms of

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Tylan General, Inc.
December 16, 1996
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certain recent business combinations in the industrial process controls and
semiconductor equipment manufacturing industries and performed such other
studies and analyses as we considered appropriate.

We have relied without independent verification upon the accuracy and
completeness of all of the financial and other information reviewed by us for
purposes of this opinion. For purposes of our analysis, and with your consent,
we have taken into account the risks and uncertainties associated with the
Company achieving management's projections in the amounts and at the times
indicated therein. In addition, we have not made an independent evaluation or
appraisal of the assets and liabilities of the Company or any of its
subsidiaries and we have not been furnished with any such evaluation or
appraisal. Our advisory services and the opinion expressed herein are provided
for the information and assistance of the Board of Directors of the Company in
connection with its consideration of the transaction contemplated by the
Agreement.

Based upon and subject to the foregoing and based upon such other matters as we
consider relevant, it is our opinion that as of the date hereof the $16.00 in
cash to be received by the holders of Shares in the Tender Offer and the
Merger, taken as a unitary transaction, is fair to such holders.

Very truly yours,

/s/ Goldman, Sachs & Co.
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GOLDMAN, SACHS & CO