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                                                                    EXHIBIT 24.2

                                POWER OF ATTORNEY

         Each of the undersigned does hereby appoint CELIA A. COLBERT and MARY
M. McDONALD, and each of them severally, to be his or her true and lawful
attorney or attorneys to execute on behalf of the undersigned (whether on behalf
of Merck & Co., Inc., or as an officer or director thereof, or by attesting the
seal of the Company, or otherwise) any Registration Statements in connection
with the registration under the Securities Act of 1933, as amended, of shares of
Common Stock of Merck & Co., Inc. which may be issued pursuant to the plans and
the plan interests covered by this Registration Statement, including amendments
thereto and all other documents in connection therewith.

         IN WITNESS WHEREOF, this instrument has been duly executed as of the
17th day of December, 1996.

                                MERCK & CO., INC.

                                By       /s/ Raymond V. Gilmartin
                                         --------------------------------------
                                         Raymond V. Gilmartin
                                         Chairman of the Board,
                                         President and Chief Executive
                                         Officer (Principal Executive Officer;
                                         Director)

   /s/ Judy C. Lewent         Senior Vice President and Chief Financial Officer
   ----------------------
   Judy C. Lewent             (Principal Financial Officer)

   /s/ Peter E. Nugent        Vice President, Controller
   ----------------------
   Peter E. Nugent            (Principal Accounting Officer)

                                    DIRECTORS

   /s/ H. Brewster Atwater, Jr.                         /s/ Lloyd C. Elam
   ------------------------------                       ---------------------
   H. Brewster Atwater, Jr.                             Lloyd C. Elam


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         /s/ Derek Birkin                              /s/ Charles E. Exley, Jr.
         -------------------------                     -------------------------
         Derek Birkin                                  Charles E. Exley, Jr.

         /s/ Lawrence A. Bossidy                       /s/ William N. Kelley
         -------------------------                     -------------------------
         Lawrence A. Bossidy                           William N. Kelley

         /s/ William G. Bowen                          /s/ Samuel O. Thier
         -------------------------                     -------------------------
         William G. Bowen                              Samuel O. Thier

         /s/ Carolyne K. Davis                         /s/ Dennis Weatherstone
         -------------------------                     -------------------------
         Carolyne K. Davis                             Dennis Weatherstone


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                             CERTIFIED RESOLUTION OF

                               BOARD OF DIRECTORS

         I, Dolores O. Rosinski, Senior Assistant Secretary of Merck & Co.,
Inc., a Corporation duly organized and existing under the laws of the State of
New Jersey, do hereby certify that the following is a true copy of a resolution
adopted on December 17, 1996, at a meeting of the Directors of said Corporation
held in the City of New York, State of New York, duly called in accordance with
the provisions of the By-Laws of said Corporation, and at which a quorum of
Directors was present:

                  RESOLVED, that the proper officers of Merck & Co., Inc. (the
         "Company") are hereby authorized and directed on behalf of the Company
         to prepare, execute and file with the Securities and Exchange
         Commission (the "SEC") Registration Statements and any and all
         amendments thereto, and any and all exhibits and other documents
         relating thereto or required by law or regulation in connection
         therewith, for the registration under the Securities Act of 1933 of the
         shares of Common Stock of the Company and the plan interests which may
         be purchased under the Base Salary Deferral Plan and the incentive
         plans covered by Registration Statement No. 33-51235 (the "Plans");

                  RESOLVED, that Celia A. Colbert is hereby appointed and
         designated the person duly authorized to receive communication and
         notices from the SEC with respect to such Registration Statements or
         any amendments thereto and as agent for service of process;

                  RESOLVED, that each officer, director or employee of the
         Company who may be required to execute such Registration Statements or
         any amendments thereto (whether on behalf of the Company, or as an
         officer or director thereof, or by attesting the seal of the Company,
         or on behalf of the Plans, or otherwise), is hereby authorized to
         execute a power of attorney appointing Celia A. Colbert and Mary M.
         McDonald, and each of them severally, his or her true and lawful
         attorney or attorneys to execute in his or her name, place and stead
         (in any such capacity) such Registration Statements and any and all
         amendments thereto and any and all exhibits and other documents
         necessary or incidental in connection therewith, and to file the same
         with the SEC, each of said attorneys to have power to act with or
         without the other, and to have full power and authority to do and
         perform in the name and on behalf of each of said officers, directors
         and employees, or any of them, as the case may be, every act whatsoever
         necessary or advisable to be done in


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         the premises as fully and to all intents and purposes as any such
         officer, director or employee might or could do in person;

                  RESOLVED, that the proper officers of the Company are hereby
         authorized and directed to arrange with the New York Stock Exchange and
         the Philadelphia Stock Exchange for the listing of the additional
         shares of the Common Stock of the Company to be issued in connection
         with the Plans; and

                  RESOLVED, that the proper officers of the Company, with the
         advice of counsel, are hereby authorized to take any action and to
         execute and deliver any letters, documents, agreements or other
         instruments as they deem necessary, appropriate or desirable to carry
         out the purposes and intents of this Special Resolution.

         IN WITNESS WHEREOF, I have hereunto subscribed my signature and affixed
the seal of the Corporation this 17th day of December, 1996.

[Corporate Seal]


                                                   /s/ Dolores O. Rosinski
                                                   -----------------------------
                                                   Senior Assistant Secretary


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