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                                 RESTATED BYLAWS
                                        OF
                        THERAPEUTIC DISCOVERY CORPORATION


                     REGISTERED OFFICE AND REGISTERED AGENT

     l.   REGISTERED OFFICE.  The registered office of the corporation shall
be in the City of Wilmington, County of New Castle, State of Delaware.

     2.   OTHER OFFICES.  The corporation may also have offices at such other
places, both within or without the State of Delaware, as the Board of
Directors may from time to time determine or the business of the corporation
may require.

                             MEETINGS OF STOCKHOLDERS

     3.   TIME AND PLACE OF MEETINGS.  All meetings of the stockholders shall
be held at such time and place, either within or without the State of
Delaware, as shall be fixed by the Board of Directors and stated in the
notice or waiver of notice of the meeting.

     4.   ANNUAL MEETING.  An annual meeting of the stockholders for the
election of directors and for the transaction of such other business as may
properly come before the meeting, shall be held on such date and at such time
and place as the Board of Directors shall each year designate.

     5.   SPECIAL MEETINGS.  Special meetings of the stockholders, for any
purpose or purposes prescribed in the notice of meeting, may be called only
by the Board of Directors,


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the Chairman of the Board or the President of the corporation.

     6.   NO ACTION WITHOUT MEETING.  Except as otherwise provided in the
Certificate of Incorporation, at any time when the corporation has more than
one stockholder of any class of capital stock, no action required to be taken
or which may be taken at any annual or special meeting of the stockholders of
such class of capital stock of the corporation may be taken without a
meeting, and the power of stockholders to consent in writing, without a
meeting, to the taking of any action is specifically denied.  Notwithstanding
the foregoing, the holder or holders of the Class B Common Stock may take any
action permitted to be taken by such holders as a class by written consent
without a meeting.

     7.   NOTICE.

          (a)  Written notice of the place, date, and time of all meetings of
the stockholders shall be given, not less than ten nor more than sixty days
before the date on which the meeting is to be held, to each stockholder
entitled to vote at such meeting, except as otherwise provided herein or
required by law (meaning, here and hereinafter, as required from time to time
by the Delaware General Corporation Law or the Certificate of Incorporation
of the corporation).

          (b)  When a meeting is adjourned to another place, date or time,
written notice need not be given of the adjourned meeting if the place, date
and time thereof are announced at the meeting at which the adjournment is
taken and the adjournment is


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not for more than thirty days; provided however, that if the date of any
adjourned meeting is more than thirty days after the date for which the
meeting was originally noticed, or if a new record date is fixed for the
adjourned meeting, written notice of the place, date, and time of the
adjourned meeting shall be given in conformity herewith.  At any adjourned
meeting, any business may be transacted which might have been transacted at
the original meeting.

     8.   NOMINATIONS AND PROPOSALS.

          (a)  The Board of Directors of the corporation may nominate
candidates for election as directors of the corporation and may propose such
other matters for approval of the stockholders as the board deems necessary
or appropriate.

          (b)  Any stockholder entitled to vote for directors may nominate
candidates for election as directors of the corporation; provided, however,
that so long as the corporation has more than one stockholder, no nominations
for director of the corporation by any person other than the Board of
Directors shall be presented to any meeting of stockholders unless the person
making the nomination is a record stockholder and shall have delivered a
written notice to the Secretary of the corporation no later than the close of
business 60 days in advance of the stockholder meeting or ten days after the
date on which notice of the meeting is first given to the stockholders,
whichever is later.  Such notice shall (i) set forth the name and address of
the person advancing such nomination and the nominee, together with such


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information concerning the person making the nomination and the nominee as
would be required by the appropriate Rules and Regulations of the Securities
and Exchange Commission to be included in a proxy statement soliciting
proxies for the election of such nominee, and (ii) shall include the duly
executed written consent of such nominee to serve as director if elected.

          (c)  No proposal by any person other than the Board of Directors
shall be submitted for the approval of the stockholders at any regular or
special meeting of the stockholders of the corporation unless the person
advancing such proposal shall have delivered a written notice to the
Secretary of the corporation no later than the close of business 60 days in
advance of the stockholder meeting or ten days after the date on which notice
of the meeting is first given to the stockholders, whichever is later. Such
notice shall set forth the name and address of the person advancing the
proposal, any material interest of such person in the proposal, and such
other information concerning the person making such proposal and the proposal
itself as would be required by the appropriate Rules and Regulations of the
Securities and Exchange Commission to be included in a proxy statement
soliciting proxies for the proposal.

     9.   QUORUM AND REQUIRED VOTE.

          (a)  At any meeting of the stockholders, the holders of a majority
of all of the shares of the stock entitled to vote on the subject matter at
the meeting, present in person or by proxy, shall constitute a quorum, unless
or except to the extent that


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the presence of a larger number may be required by law.  Except as otherwise
provided in these bylaws or as otherwise required by law, the affirmative
vote of a majority of shares present in person or represented by proxy at the
meeting and entitled to vote on the subject matter shall be the act of the
stockholders.

          (b) If a quorum shall fail to attend any meeting, the chairman of
the meeting or the holders of a majority of the shares of stock entitled to
vote who are present, in person or by proxy, may adjourn the meeting to
another place, date, or time.

          (c) If a notice of any adjourned special meeting of stockholders is
sent to all stockholders entitled to vote thereat, stating that it will be
held with those present constituting a quorum, then except as otherwise
provided in these bylaws or as otherwise required by law, those present at
such adjourned meeting shall constitute a quorum, and all matters shall be
determined by a majority of the votes cast at such meeting.

     10.  ORGANIZATION.  The Chairman of the Board or, in his or her absence,
the President of the Corporation or, in the absence of both, such person as
may be designated by the Board of Directors or, if there is no such
designation, such person as may be chosen by the holders of a majority of the
shares entitled to vote who are present, in person or by proxy, shall call to
order any meeting of the stockholders and act as chairman of the meeting.

     11.  CONDUCT OF BUSINESS.  The chairman of any meeting of


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stockholders shall determine the order of business and the procedure at the
meeting, including such regulation of the manner of voting and the conduct of
discussion as seem to him or her in order.

     12.  PROXIES AND VOTING.  At any meeting of the stockholders, every
stockholder entitled to vote may vote in person or by proxy authorized by an
instrument in writing filed in accordance with the procedures established for
the meeting.

     13.  STOCK LIST.  A complete list of stockholders entitled to vote at
any meeting of stockholders, arranged in alphabetical order and showing the
address of each such stockholder and the number of shares of each class
registered in his or her name, shall be open to the examination of any
stockholder, for any purpose germane to the meeting, during ordinary business
hours for a period of at least ten days prior to the meeting, either at a
place within the city where the meeting is to be held, which place shall be
specified in the notice of the meeting, or if not so specified, at the place
where the meeting is to be held. The stock list shall also be kept at the
place of the meeting during the whole time thereof and shall be open to the
examination of any such stockholder present.


                              BOARD OF DIRECTORS

     14.  POWERS.  The business and affairs of the corporation shall be
managed by or under the direction of its Board of Directors.


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     15.  NUMBER, CLASSIFICATION AND TERM OF OFFICE. The number of directors
of the corporation who shall constitute the whole board shall be five but may
be increased or decreased from time to time either by a resolution or bylaw
duly adopted by the Board of Directors.  The Board of Directors shall be and
is divided into three classes: Class I, Class II and Class III, which shall
be as nearly equal in number as possible.  Each director shall serve for a
term ending on the date of the third annual meeting of stockholders following
the annual meeting at which the director was elected; provided, however, that
each initial director in Class I shall hold office until the annual meeting
of stockholders in 1994; each initial director in Class II shall hold office
until the annual meeting of stockholders in 1995; and each initial director
in Class III shall hold office until the annual meeting of stockholders in
1996.  Notwithstanding the foregoing, each director shall serve until his
successor is duly elected and qualified or until his death, resignation or
removal.

     16.  REMOVAL.  During any period when the Board of Directors is divided
into classes, any director may be removed from office only with cause, and
then only by the holders of a majority of the shares entitled to vote in an
election of directors.

     17.  RESIGNATIONS.  A director may resign at any time by giving written
notice to the corporation.  Such resignation shall be effective when given
unless the director specifies a later time.  The resignation shall be
effective regardless of whether it is accepted by the corporation.


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     18.  NEWLY-CREATED DIRECTORSHIPS AND VACANCIES.  During any period when
the Board of Directors is divided into classes, in the event of any increase
or decrease in the authorized number of directors, any newly-created or
eliminated directorships resulting from such increase or decrease shall be
apportioned by the Board of Directors among the three classes of directors so
as to maintain such classes as nearly equal in number as possible. Whether or
not the board is classified, no decrease in the number of directors
constituting the Board of Directors shall shorten the term of any incumbent
director. Except as otherwise provided in the corporation's Certificate of
Incorporation, newly-created directorships resulting from any increase in the
number of directors and any vacancies on the Board of Directors resulting
from death, resignation, disqualification, removal or other cause shall be
filled by the affirmative vote of a majority of the remaining directors then
in office (and not by stockholders), even though less than a quorum of the
Board of Directors.  Any director elected in accordance with the preceding
sentence shall hold office for the remainder of the full term of the class of
directors in which the directorship was created or the vacancy occurred and
until such director's successor shall have been elected and qualified.

     19.  REGULAR MEETINGS.  Regular meetings of the Board of Directors shall
be held at such place or places, on such date or dates, and at such time or
times as shall have been established by the Board of Directors and publicized
among all directors.  A


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notice of each regular meeting shall not be required.

     20.  SPECIAL MEETINGS.  Special meetings of the Board of Directors may
be called by the Chairman of the Board, the President or any two directors.

     21.  NOTICE OF MEETINGS.

          (a)  Special meetings and regular meetings not fixed as provided in
these Bylaws, shall be held upon four days' notice by mail or two days'
notice delivered personally or by telephone or telegraph to each director who
does not waive such notice.  The notice shall state the place, date and time
of the meeting. Unless otherwise indicated in the notice, any and all
business may be transacted at a special meeting.

          (b)  Notice of a reconvened meeting need not be given if the place,
date and time of the reconvened meeting are announced at the meeting at which
the adjournment is taken and the adjournment is not for more than 24 hours.
If a meeting is adjourned for more than 24 hours, notice of the reconvened
meeting shall be given prior to the time of that reconvened meeting to the
directors who were not present at the time of adjournment.

     22.  ACTION WITHOUT MEETING.  Except as required by law, any action
required or permitted to be taken at any meeting of the Board of Directors or
any committee thereof may be taken without a meeting if all members of the
Board of Directors or any committee thereof, as the case may be, consent
thereto in writing and the writing or writings are filed with the minutes of
the


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Board of Directors or committee.

     23.  MEETING BY TELEPHONE.  Except as required by law, members of the
Board of Directors, or of any committee thereof may participate in the
meeting of the Board of Directors or committee by means of conference
telephone or similar communications equipment if all persons who participate
in the meeting can hear each other. Such participation shall constitute
presence in person at such meeting.

     24.  QUORUM AND MANNER OF ACTING.  At any meeting of the Board of
Directors, a majority of the directors then in office shall constitute a
quorum for all purposes.  A meeting at which a quorum is initially present
may continue to transact business notwithstanding the withdrawal of
directors.  If a quorum shall fail to attend any meeting, a majority of those
present may adjourn the meeting to another place, date, or time, without
further notice or waiver thereof.  Except as provided herein, the act of the
majority of the directors present at any meeting at which a quorum is present
shall be the act of the Board of Directors.

     25.  COMMITTEES OF THE BOARD OF DIRECTORS.  The Board of Directors, by a
vote of a majority of the whole Board, may from time to time designate
committees of the Board, with such lawfully delegable powers and duties as it
thereby confers, to serve at the pleasure of the Board and shall, for those
committees and any others provided for herein, elect a director or directors
to serve as the member or members, designating, if


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it desires, other directors as alternate members who may replace any absent
or disqualified member at any meeting of the committee. Any committee so
designated may exercise the power and authority of the Board of Directors to
declare a dividend or to authorize the issuance of stock if the resolution
which designates the committee or a supplemental resolution of the Board of
Directors shall so provide.  The principles set forth in Sections 14 through
24 of these Bylaws shall apply to committees of the Board of Directors and to
actions taken by such committees.

     26.  COMPENSATION OF DIRECTORS.  Unless otherwise restricted by the
Certificate of Incorporation or these Bylaws the Board of Directors shall
have the authority to fix the compensation of directors.  The directors may
be paid their expenses, if any, of attendance at each meeting of the Board of
Directors or a committee thereof and may receive fixed fees and other
compensation for their services as directors.  No such payment shall preclude
any director from serving the corporation in any other capacity and receiving
compensation for such service.

                                   OFFICERS

     27.  TITLES.  The officers of the corporation shall be chosen by the
Board of Directors and shall include a Chairman of the Board or a President
or both and a Secretary.  The Board of Directors may also appoint a Treasurer
and one or more Vice Presidents, Assistant Secretaries, Assistant Treasurers
or other


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officers.  Any number of offices may be held by the same person. All officers
shall perform their duties and exercise their powers subject to the Board of
Directors.

     28.  ELECTION, TERM OF OFFICE AND VACANCIES. The officers shall be
elected annually by the Board of Directors at its regular meeting following
the annual meeting of the stockholders and each officer shall hold office
until the next annual election of officers and until the officer's successor
is elected and qualified or until the officers death, resignation or removal.
Any officer may be removed at any time, with or without cause, by the Board
of Directors.  Any vacancy occurring in any office may be filled by the Board
of Directors.

     29.  RESIGNATION.  Any officer may resign at any time upon notice to the
corporation without prejudice to the rights, if any, of the corporation under
any contract to which the officer is a party.  The resignation of an officer
shall be effective when given unless the officer specifies a later time.  The
resignation shall be effective regardless of whether it is accepted by the
corporation.

     30.  CHIEF EXECUTIVE OFFICER.  The Board of Directors shall designate
either the Chairman of the Board or the President as the chief executive
officer and may prescribe the duties and powers of the chief executive
officer.  In the absence of such a designation, the Chairman of the Board
shall be the chief executive officer. If there is no Chairman of the Board,
the President shall be the chief executive officer.  Subject to the


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provisions of these Bylaws and to the direction of the Board of Directors, the
chief executive officer shall have the responsibility for the general management
and control of the business and affairs of the corporation and shall perform all
duties and have all powers which are commonly incident to the office of chief
executive or which are delegated to him or her by the Board of Directors.
Either the Chairman of the Board or the President and such other officers as
may, from time to time be expressly designated by the Board of Directors shall
have the power to sign all stock certificates, contracts and other instruments
of the Corporation which are authorized.

     31.  SECRETARY AND ASSISTANT SECRETARIES.  The Secretary shall issue all
authorized notices for and shall keep minutes of all meetings of the
stockholders and the Board of Directors.  He or she shall have charge of the
corporate books and shall perform such other duties as the Board of Directors
may from time to time prescribe. At the request of the Secretary, or in the
Secretary's absence or disability, any Assistant Secretary shall perform any
of the duties of the Secretary and when so acting shall have all the powers
of and be subject to all the restrictions upon, the Secretary.

     32.  OTHER OFFICERS.  The other officers of the corporation, if any,
shall exercise such powers and perform such duties as the Board of Directors
or the chief executive officer shall prescribe.

     33.  COMPENSATION.  The Board of Directors shall fix the


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compensation of the chief executive officer and may fix the compensation of
other employees of the corporation, including the other officers.  If the
Board does not fix the compensation of the other officers, the chief
executive officer shall fix such compensation.

     34.  ACTIONS WITH RESPECT TO SECURITIES OF OTHER CORPORATIONS.  Unless
otherwise directed by the Board of Directors, the Chairman of the Board, the
president or any officer of the corporation authorized by the Chairman of the
Board or the president, shall have power to vote and otherwise act on behalf
of the corporation, in person or by proxy, at any meeting of stockholders of,
or with respect to any action of stockholders of, any other corporation in
which the corporation may hold securities and otherwise shall have power to
exercise any and all rights and powers which the corporation may possess by
reason of its ownership of securities in such other corporation.

                              STOCK AND DIVIDENDS

     35.  CERTIFICATES OF STOCK.  Each stockholder shall be entitled to a
certificate signed by, or in the name of, the corporation by the Chairman,
the President or a Vice President, and by the Secretary or an Assistant
Secretary, or a Treasurer or an Assistant Treasurer, certifying the number of
shares owned by him or her.  Any or all of the signatures on the certificate
may be facsimile.


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     36.  TRANSFERS OF STOCK.  Transfers of stock shall be made only upon the
transfer books of the corporation kept at an office of the corporation or by
transfer agents designated to transfer shares of the stock of the
corporation. Except where a certificate is issued in accordance with the next
sentence of this Section, an outstanding certificate for the number of shares
involved shall be surrendered for cancellation before a new certificate is
issued therefor.  In the event of the loss, theft or destruction of any
certificate of stock, another may be issued in its place pursuant to such
regulations as the Board of Directors may establish concerning proof of such
loss, theft or destruction and concerning the giving of a satisfactory bond
or bonds of indemnity.

     37.  REGULATIONS.  The issue, transfer, conversion and registration of
certificates of stock shall be governed by such other regulations as the
Board of Directors may establish.

                                  RECORD DATE

     38.  RECORD DATE.  In order that the corporation may determine the
stockholders entitled to notice of or to vote at any meeting of stockholders
or any adjournment thereof, or entitled to receive payment of any dividend or
other distribution or allotment of any rights, or entitled to exercise any
rights in respect of any change, conversion or exchange of stock or for the
purpose of any other lawful action, the Board of Directors may fix in advance
a record date, which shall not be more than 60 nor


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less than ten days before the date of such meeting, nor more than 60 days
prior to any other action.  If no record date is fixed, the record date (1)
for determining stockholders entitled to notice of or to vote at a meeting of
stockholders shall be at the close of business on the day next preceding the
day on which notice is given or, if notice is waived, at the close of
business on the day next preceding the day on which the meeting is held; and
(2) for determining stockholders for any other purpose shall be at the close
of business on the day on which the Board of Directors adopts the resolution
relating thereto.  A determination of stockholders of record entitled to
notice of or to vote at a meeting of stockholders shall apply to any
adjournment of the meeting; provided, however, that the Board of Directors
may fix a new record date for the reconvened meeting.

                                 WAIVER OF NOTICE

     39.  WAIVER OF NOTICE.  Whenever notice is required to be given by law
or these Bylaws, a written waiver of notice, signed by the person entitled to
notice, whether before or after the time stated therein, shall be deemed
equivalent to notice.  Attendance of a person at a meeting shall constitute a
waiver of notice of such meeting, except when the person attends a meeting
for the express purpose of objecting, at the beginning of the meeting, to the
transaction of any business because the meeting is not lawfully called or
convened.  Unless so required by the Certificate of Incorporation or these
Bylaws, neither the


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business to be transacted at, nor the purpose of any regular or special
meeting of the stockholders, directors or members of a committee of directors
need be specified in any written waiver of notice.

                                   AMENDMENTS

     40.  AMENDMENTS.  These Bylaws may be amended or repealed or new bylaws
may be adopted by the stockholders or by the Board of Directors.

                                  MISCELLANEOUS

     41.  FISCAL YEAR.  The fiscal year of the corporation shall be as fixed
by the Board of Directors.

     42.  TIME PERIODS.  In applying any provision of these Bylaws which
requires that an act be done or not done within a specified number of days
prior to an event, calendar days shall be used, the day of doing of the act
shall be excluded, and the day of the event shall be included.

     43.  FACSIMILE SIGNATURES.  In addition, to the provisions for use of
facsimile signature elsewhere specifically authorized in these Bylaws,
facsimile signatures of any officer or officers of the corporation may be
used whenever and as authorized by the Board of Directors.

     44.  CORPORATE SEAL. The Board of Directors may provide a suitable seal,
containing the name of the corporation, which seal shall be in the charge of
the Secretary.  Duplicates of the seal


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may be kept and used by a Treasurer or by an Assistant Secretary or Assistant
Treasurer.

     45.  RELIANCE UPON BOOKS, REPORTS AND RECORDS.  Each director, each
member of any committee designated by the Board of Directors, and each
officer of the corporation shall, in the performance of his or her duties, be
fully protected in relying in good faith upon the books of account or other
records of the corporation, including reports made to the corporation by any
of its officers, by an independent certified public accountant or by an
appraiser.





     This is to certify that these Bylaws were duly adopted by the Board of
Directors of this corporation on January 26, 1994.







                                                   /s/ David R. Hoffmann
                                                   ----------------------
                                                   DAVID R. HOFFMANN
                                                   Secretary








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