Exhibit 8.2


                      [LETTERHEAD OF LATHAM & WATKINS LLP]

                                         , 2004


Axon Instruments, Inc.
3280 Whipple Road
Union City, CA 94587

      RE: AGREEMENT AND PLAN OF MERGER AND REORGANIZATION BY AND AMONG MOLECULAR
DEVICES CORPORATION, ASTROS ACQUISITION SUB I, INC., ASTROS ACQUISITION SUB II,
LLC, AND AXON INSTRUMENTS, INC., DATED AS OF MARCH 20, 2004

Ladies and Gentlemen:

            We have acted as counsel to Axon Instruments, Inc., a California
corporation ("Axon"), in connection with (1) the proposed merger of Astros
Acquisition Sub I, Inc., a California corporation ("Merger Sub I") and a wholly
owned subsidiary of Molecular Devices Corporation, a Delaware corporation
("Molecular Devices"), with and into Axon ("Merger I"), and (2) immediately
following the effectiveness of Merger I, a merger of Axon with and into Astros
Acquisition Sub II, LLC, a California limited liability company ("Merger Sub
II," and together with Merger Sub I, the "Merger Subs") and a wholly owned
subsidiary of Molecular Devices ("Merger II," and together with Merger I, the
"Mergers"), pursuant to an Agreement and Plan of Merger and Reorganization by
and among Molecular Devices, the Merger Subs and Axon dated as of March 20, 2004
(the "Merger Agreement"), the California General Corporation Law and the
Beverly-Killea Limited Liability Company Act. This opinion is being delivered in
connection with Molecular Device's Registration Statement on Form S-4 relating
to the proposed Mergers pursuant to the Merger Agreement (the "Registration
Statement"). Capitalized terms not defined herein have the meanings specified in
the Merger Agreement.

            In rendering our opinion, we have examined and, with your consent,
are expressly relying upon (without any independent investigation or review
thereof) the truth and accuracy of the statements, covenants, representations
and warranties contained in (i) the Merger Agreement (including any Exhibits,
Annexes and Schedules thereto), (ii) the Registration Statement, and (iii) such
other documents and corporate records as we have deemed necessary or appropriate
for purposes of our opinion.

            In addition, we have assumed, with your consent, that:

            1. Original documents (including signatures) are authentic and
            documents submitted to us as copies conform to the original
            documents;

            2. The Mergers will be consummated in the manner contemplated by,
            and in accordance with the provisions of, the Merger Agreement and
            the Registration Statement, and the Mergers will be effective under
            applicable state law;

            3. All statements, descriptions and representations contained in any
            of the documents referred to herein or otherwise made to us are
            true, complete and correct, and no actions have been taken or will
            be taken which are inconsistent with such statements, descriptions
            or representations or which make any such statements, descriptions
            or representations untrue, incomplete or incorrect at the Effective
            Time;

            4. Any statements made in any of the documents referred to herein
            "to the knowledge of" or similarly qualified are true, complete and
            correct and will continue to be true, complete and correct at all
            times up to and including the Effective Time, in each case without
            such qualification; and

            5. The parties have complied with and, if applicable, will continue
            to comply with, the covenants contained in the Merger Agreement and
            the Registration Statement.

            Based upon and subject to the foregoing, and subject to the
qualifications and limitations stated in the Registration Statement, the
statements under the caption "The Mergers - Material U.S. Federal Income Tax
Consequences," insofar as they purport to summarize certain provisions of the
statutes or regulations referred to therein, are accurate summaries in all
material respects.

            In addition to the matters set forth above, this opinion is subject
to the exceptions, limitations and qualifications set forth below.

            1. This opinion represents our best judgment regarding the
            application of United States federal income tax laws arising under
            the Internal Revenue Code of 1986, as amended, existing judicial
            decisions, administrative regulations and published rulings and
            procedures. Our opinion is not binding upon the Internal Revenue
            Service or the courts, and there is no assurance that the Internal
            Revenue Service will not assert a contrary position. Furthermore, no
            assurance can be given that future legislative, judicial or
            administrative changes, on either a prospective or retroactive
            basis, would not adversely affect the accuracy of the conclusions
            stated herein. Nevertheless, we undertake no responsibility to
            advise you of any new developments in the application or
            interpretation of the United States federal income tax laws.

            2. No opinion is expressed as to any transaction other than the
            Mergers as described in the Merger Agreement, or to any transaction
            whatsoever, including the Mergers, if, to the extent relevant to our
            opinion, either all the transactions described in the Merger
            Agreement are not consummated in accordance with the

            terms of the Merger Agreement and without waiver or breach of any
            provisions thereof or all of the representations, warranties,
            statements and assumptions upon which we have relied are not true
            and accurate at all relevant times.


            This opinion is rendered only to you, and is for your use in
connection with Molecular Device's filing of the Registration Statement upon the
understanding that we are not hereby assuming professional responsibility to any
other person whatsoever. This opinion may not be relied upon by you for any
other purpose or relied upon by any other person, firm or corporation, for any
purpose, without our prior written consent in each instance, provided, however,
that this opinion may be relied upon by persons entitled to rely on it pursuant
to applicable provisions of federal securities law. We consent to the filing of
this opinion as an exhibit to the Registration Statement and to the reference to
our firm name therein under the caption "Legal Matters." In giving this consent,
we do not admit that we are within the category of persons whose consent is
required under Section 7 of the Securities Act of 1933, as amended, or the rules
or regulations of the Securities and Exchange Commission promulgated thereunder.


                                       Very truly yours,