Bylaws - Maxygen Inc.


                                    BYLAWS
                                      OF
                                 MAXYGEN, INC.

                                   ARTICLE I

                                    OFFICES

          Section 1.  The registered office shall be in the City of Dover,
County of Kent, State of Delaware.

          Section 2.  The corporation may also have offices at such other places
both within and without the State of Delaware as the board of directors may from
time to time determine or the business of the corporation may require.

                                  ARTICLE II

                           MEETINGS OF STOCKHOLDERS

          Section 1.  All meetings of the stockholders for the election of
directors shall be held in the County of Santa Clara, State of California, at
such place as may be fixed from time to time by the board of directors, or at
such other place either within or without the State of Delaware as shall be
designated from time to time by the board of directors and stated in the notice
of the meeting.  Meetings of stockholders for any other purpose may be held at
such time and place, within or without the State of Delaware, as shall be stated
in the notice of the meeting or in a duly executed waiver of notice thereof.

          Section 2.  Annual meetings of stockholders, shall be held on the
first Tuesday of the fifth calendar month following the end of the corporation's
fiscal year if not a legal holiday, and if a legal holiday, then on the next
secular day following, at 11:00 A.M., or at such 

 
other date and time as shall be designated from time to time by the board of
directors and stated in the notice of the meeting, at which they shall elect by
a plurality vote a board of directors, and transact such other business as may
properly be brought before the meeting.

          Section 3.  Written notice of the annual meeting stating the place,
date and hour of the meeting shall be given to each stockholder entitled to vote
at such meeting not less than ten nor more than sixty days before the date of
the meeting.

          Section 4.  The officer who has charge of the stock ledger of the
corporation shall prepare and make, at least ten days before every meeting of
stockholders, a complete list of the stockholders entitled to vote at the
meeting, arranged in alphabetical order, and showing the address of each
stockholder and the number of shares registered in the name of each stockholder.
Such list 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 list shall also be produced and kept at the time and place of the meeting
during the whole time thereof, and may be inspected by any stockholder who is
present.

          Section 5.  Special meetings of the stockholders, for any purpose or
purposes, unless otherwise prescribed by statute or by the certificate of
incorporation, may be called by the chairman, if one has been appointed, and
shall be called by the chairman or secretary at the request in writing of a
majority of the board of directors, or at the request in writing of stockholders
owning a majority in amount of the entire capital stock of the corporation
issued and outstanding and entitled to vote.  Such request shall state the
purpose or purposes of the proposed meeting.

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          Section 6.  Written notice of a special meeting stating the place,
date and hour of the meeting and the purpose or purposes for which the meeting
is called, shall be given not less than ten nor more than sixty days before the
date of the meeting, to each stockholder entitled to vote at such meeting.

          Section 7.  Business transacted at any special meeting of stockholders
shall be limited to the purposes stated in the notice.

          Section 8.  The holders of a majority of the stock issued and
outstanding and entitled to vote thereat, present in person or represented by
proxy, shall constitute a quorum at all meetings of the stockholders for the
transaction of business except as otherwise provided by statute or by the
certificate of incorporation.  If, however, such quorum shall not be present or
represented at any meeting of the stockholders, the stockholders entitled to
vote thereat, present in person or represented by proxy, shall have power to
adjourn the meeting from time to time, without notice other than announcement at
the meeting, until a quorum shall be present or represented.  At such adjourned
meeting at which a quorum shall be present or represented any business may be
transacted which might have been transacted at the meeting as originally
notified.  If the adjournment is for more than thirty days, or if after the
adjournment a new record date is fixed for the adjourned meeting, a notice of
the adjourned meeting shall be given to each stockholder of record entitled to
vote at the meeting.

          Section 9.  When a quorum is present at any meeting, the vote of the
holders of a majority of the stock having voting power present in person or
represented by proxy shall decide any question brought before such meeting,
unless the question is one upon which by express provision of the statutes or of
the certificate of incorporation, a different vote is required in which case
such express provision shall govern and control the decision of such question.

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          Section 10.  Unless otherwise provided in the certificate of
incorporation each stockholder shall at every meeting of the stockholders be
entitled to one vote in person or by proxy for each share of the capital stock
having voting power held by such stockholder, but no proxy shall be voted on
after three years from its date, unless the proxy provides for a longer period.

          Section 11.  Unless otherwise provided in the certificate of
incorporation, any action required to be taken at any annual or special meeting
of stockholders of the corporation, or any action which may be taken at any
annual or special meeting of such stockholders, may be taken without a meeting,
without prior notice and without a vote, if a consent in writing, setting forth
the action so taken, shall be signed by the holders of outstanding stock having
not less than the minimum number of votes that would be necessary to authorize
or take such action at a meeting at which all shares entitled to vote thereon
were present and voted.  Prompt notice of the taking of the corporate action
without a meeting by less than unanimous written consent shall be given to those
stockholders who have not consented in writing.

                                  ARTICLE III

                                   DIRECTORS

          Section 1.  The number of directors which shall constitute the whole
board shall be seven (7).

          Section 2.  Except as provided in Section 3 of this Article, the
directors shall be elected at the annual meeting of the stockholders.  Each
director elected shall hold office until his successor is elected and qualified.
Directors need not be stockholders.

          Section 3.  Vacancies and newly created directorships resulting from
any increase in the authorized number of directors elected by all of the
stockholders having the right 

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to vote as a single class may be filled by a majority of the directors then in
office, though less than a quorum, or by a sole remaining director; whenever the
holders of any class or classes of stock or series thereof are entitled to elect
one or more directors by the certificate of incorporation, vacancies and newly
created directorships of such class or classes or series may be filled by a
majority of the directors elected by such class or classes or series thereof
then in office, or by a sole remaining director so elected. The directors so
chosen shall hold office until the next annual election and until their
successors are duly elected and shall qualify, unless sooner displaced. If there
are no directors in office, then an election of directors may be held in the
manner provided by statute. If, at the time of filling any vacancy or any newly
created directorship, the directors then in office shall constitute less than a
majority of the whole board (as constituted immediately prior to any such
increase), the Court of Chancery may, upon application of any stockholder or
stockholders holding at least ten percent of the total number of the shares at
the time outstanding having the right to vote for such directors, summarily
order an election to be held to fill any such vacancies or newly created
directorships, or to replace the directors chosen by the directors then in
office.

          Section 4.  The business of the corporation shall be managed by or
under the direction of its board of directors which may exercise all such powers
of the corporation and do all such lawful acts and things as are not by statute
or by the certificate of incorporation or by these by-laws directed or required
to be exercised or done by the stockholders.

                      MEETINGS OF THE BOARD OF DIRECTORS

          Section 5.  The board of directors of the corporation may hold
meetings, both regular and special, either within or without the State of
Delaware.

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          Section 6.  The first meeting of each newly elected board of directors
shall be held at such time and place as shall be fixed by the vote of the
stockholders at the annual meeting and no notice of such meeting shall be
necessary to the newly elected directors in order legally to constitute the
meeting, provided a quorum shall be present.  In the event of the failure of the
stockholders to fix the time or place of such first meeting of the newly elected
board of directors, or in the event such meeting is not held at the time and
place so fixed by the stockholders, the meeting may be held at such time and
place as shall be specified in a notice given as hereinafter provided for
special meetings of the board of directors, or as shall be specified in a
written waiver signed by all of the directors.

          Section 7.  Regular meetings of the board of directors may be held
without notice at such time and at such place as shall from time to time be
determined by the board.

          Section 8.  Special meetings of the board may be called by the
chairman on one day's notice to each director, either personally or by mail or
by telegram; special meetings shall be called by the chairman or secretary in
like manner and on like notice on the written request of two directors unless
the board consists of only one director in which case special meetings shall be
called by the chairman or secretary in like manner and on like notice on the
written request of the sole director.

          Section 9.  At all meetings of the board a majority of the directors
shall constitute a quorum for the transaction of business and the act of a
majority of the directors present at any meeting at which there is a quorum
shall be the act of the board of directors, except as may be otherwise
specifically provided by statute or by the certificate of incorporation.  If a
quorum shall not be present at any meeting of the board of directors the
directors present 

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thereat may adjourn the meeting from time to time, without notice other than
announcement at the meeting, until a quorum shall be present.

          Section 10.  Unless otherwise restricted by the certificate of
incorporation or these by-laws, any action required or permitted to be taken at
any meeting of the board of directors or of any committee thereof may be taken
without a meeting, if all members of the board or committee, as the case may be,
consent thereto in writing, and the writing or writings are filed with the
minutes of the proceedings of the board or committee.

          Section 11.  Unless otherwise restricted by the certificate of
incorporation or these by-laws, members of the board of directors, or any
committee designated by the board of directors, may participate in a meeting of
the board of directors, or any committee, by means of conference telephone or
similar communications equipment by means of which all persons participating in
the meeting can hear each other, and such participation in a meeting shall
constitute presence in person at the meeting.

                            COMMITTEES OF DIRECTORS

          Section 12.  The board of directors may, by resolution passed by a
majority of the whole board, designate one or more committees, each committee to
consist of one or more of the directors of the corporation.  The board many
designate one or more directors as alternate members of any committee, who may
replace any absent or disqualified member at any meeting of the committee.

          Any such committee, to the extent provided in the resolution of the
board of directors, shall have and may exercise all the powers and authority of
the board of directors in the management of the business and affairs of the
corporation, and may authorize the seal of the 

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corporation to be affixed to all papers which may require it; but no such
committee shall have the power or authority in reference to amending the
certificate of incorporation (except to the extent provided in resolutions of
the board of directors and permitted by the General Corporation Law of the State
of Delaware), adopting an agreement of merger or consolidation, recommending to
the stockholders the sale, lease or exchange of all or substantially all of the
corporation's property and assets, recommending to the stockholders a
dissolution of the corporation or a revocation of a dissolution, or amending the
by-laws of the corporation; and, unless the resolution or the certificate of
incorporation expressly so provide, no such committee shall have the power or
authority to declare a dividend, to authorize the issuance of stock or to adopt
a certificate of ownership and merger pursuant to the General Corporation Law of
Delaware. Such committee or committees shall have such name or names as may be
determined from time to time by resolution adopted by the board of directors.

          Section 13.  Each committee shall keep regular minutes of its meetings
and report the same to the board of directors when required.


                           COMPENSATION OF DIRECTORS

          Section 14.  Unless otherwise restricted by the certificate of
incorporation or these by-laws, 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 and may be paid
a fixed sum for attendance at each meeting of the board of directors or a stated
salary as director.  No such payment shall preclude any director from serving
the corporation in any other capacity and receiving compensation therefor.
Members of special or standing committees may be allowed like compensation for
attending committee meetings.

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                             REMOVAL OF DIRECTORS

          Section 15.  Unless otherwise restricted by the certificate of
incorporation, by-laws or statute, any director or the entire board of directors
may be removed, with or without cause, by the holders of a majority of shares
entitled to vote at an election of directors.

                                  ARTICLE IV

                                    NOTICES

          Section 1.  Whenever, under the provisions of the statutes or of the
certificate of incorporation or of these by-laws, notice is required to be given
to any director or stockholder, it shall not be construed to mean personal
notice, but such notice may be given in writing, by mail, addressed to such
director or addressed to such director or stockholder, at his address as it
appears on the records of the corporation, with postage thereon prepaid, and
such notice shall be deemed to be given at the time when the same shall be
deposited in the United States mail.  Notice to directors may also be given by
telegram.

          Section 2.  Whenever any notice is required to be given under the
provisions of the statutes or of the certificate of incorporation or of these
by-laws, a waiver thereof in writing, signed by the person or persons entitled
to said notice, whether before or after the time stated therein, shall be deemed
equivalent thereto.

          Section 3.  Whenever notice is required to be given, under any
provision of the statutes or the certificate of incorporation or these by-laws
to any stockholder whom (i) notice of two consecutive annual meetings, and all
notices of meetings or of the taking of action by written consent without a
meeting to such person during the period between such two consecutive annual

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meetings, or (ii) all, and at least two, payments (if sent by first class mail)
of dividends or interest on securities during a twelve month period, have been
mailed addressed to such person at his address as shown on the records of the
corporation and have been returned undeliverable, the giving of such notice to
such person shall not be required.  If any such person shall deliver to the
corporation a written notice setting forth his then current address, notice to
such person shall be reinstated.

                                   ARTICLE V

                                   OFFICERS

          Section 1.  The officers of the corporation shall be chosen by the
board of directors and shall be a president, a secretary and a treasurer.  The
board of directors may also choose a chairman, one or more an executive vice-
presidents, one or more vice-presidents, and one or more assistant secretaries
and assistant treasurers.  Any number of offices may be held by the same person,
unless the certificate of incorporation or these by-laws otherwise provide.

          Section 2.  The board of directors at its first meeting after each
annual meeting of stockholders shall choose a president, one or more vice-
presidents, a secretary and a treasurer and may appoint a chairman.

          Section 3.  The board of directors may appoint such other officers and
agents as it shall deem necessary who shall hold their offices for such terms
and shall exercise such powers and perform such duties as shall be determined
from time to time by the board.

          Section 4.  The salaries of all officers and agents of the corporation
shall be fixed by the board of directors.

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          Section 5.  The officers of the corporation shall hold office until
their successors are chosen and qualify.  Any officer elected or appointed by
the board of directors may be removed at any time by the affirmative vote of a
majority of the board of directors.  Any vacancy occurring in any office of the
corporation shall be filled by the board of directors.

                                 THE CHAIRMAN

          Section 6.  The chairman, if one is appointed, shall be the chief
executive officer of the corporation, shall preside at all meetings of the
stockholders and the board of directors, shall have general oversight and
management of the business of the corporation and shall see that all orders and
resolutions of the board of directors are carried into effect.

          Section 7.  He shall execute bonds, mortgages and other contracts
requiring a seal, under the seal of the corporation, except where required or
permitted by law to be otherwise signed and executed and except where the
signing and execution thereof shall be expressly delegated by the board of
directors to some other officer or agent of the corporation.

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                                 THE PRESIDENT

          Section 8.  The president shall be the chief operating officer of the
corporation, shall preside at all meetings of the stockholders and board of
directors in the absence of the chairman, shall have general active management
of the day-to-day business of the corporation, and in the absence of the
chairman or in the event of his inability or refusal to act, shall perform the
duties of the chairman, and when so acting, shall have all the powers of and be
subject to all the restrictions of the chairman, and in general shall perform
all duties incident to the office at president and such other duties as may be
prescribed by the board of directors from time to time.

                              THE VICE-PRESIDENTS

          Section 9.  In the absence of the president or in the event of his
inability or refusal to act, a vice-president (or in the event there be more
than one vice-president, the vice-presidents in the order designated by the
directors, or in the absence of any designation, then in the order of their
election) shall perform the duties of the president, and when so acting, shall
have all the powers of and be subject to all the restrictions upon the
president.  The vice-presidents shall perform such other duties and have such
other powers as the board of directors may from time to time prescribe.

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                     THE SECRETARY AND ASSISTANT SECRETARY

          Section 10.  The secretary shall attend all meetings of the board of
directors and all meetings of the stockholders and record the proceedings of the
meetings of the corporation and of the board of directors in a book to be kept
for that purpose and shall perform like duties for the standing committees when
required.  He shall give, or cause to be given, notice of all meetings of the
stockholders and special meetings of the board of directors, and shall perform
such other duties as may be prescribed by the board of directors or president,
under whose supervision he shall be.  He shall have custody of the corporate
seal of the corporation and he, or an assistant secretary, shall have authority
to affix the same to any instrument requiring it and when so affixed, it may be
attested by his signature or by the signature of such assistant secretary.  The
board of directors may give general authority to any other officer to affix the
seal of the corporation and to attest the affixing of his signature.

          Section 11.  The assistant secretary, or if there be more than one,
the assistant secretaries in the order determined by the board of directors (of
if there be no such determination, then in the order of their election) shall,
in the absence of the secretary or in the event of his inability or refusal to
act, perform the duties and exercise the powers of the secretary and shall
perform such other duties and have such other powers as the board of directors
may from time to time prescribe.

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                    THE TREASURER AND ASSISTANT TREASURERS

          Section 12.  The treasurer shall have the custody of the corporate
funds and securities and shall keep full and accurate accounts of receipts and
disbursements in books belonging to the corporation and shall deposit all moneys
and other valuable effects in the name and to the credit of the corporation in
such depositories as may be designated by the board of directors.

          Section 13.  He shall disburse the funds of the corporation as may be
ordered by the board of directors, taking proper vouchers for such
disbursements, and shall render to the president and the board of directors, at
its regular meetings, or when the board of directors so requires, an account of
all his transactions as treasurer and of the financial condition of the
corporation.

          Section 14.  If required by the board of directors, he shall give the
corporation a bond (which shall be renewed every six years) in such sum and with
such surety or sureties as shall be satisfactory to the board of directors for
the faithful performance of the duties of his office and for the restoration to
the corporation, in case of his death, resignation, retirement or removal from
office, of all books, papers, vouchers, money and other property of whatever
kind in his possession or under his control belonging to the corporation.

          Section 15.  He shall, in general perform all the duties incident to
the office of treasurer, including the development of financial statements based
on existing facts, together with recommendations to the president regarding all
fiscal matters; provided, however, that he shall not have the authority to make
any material financial decisions without approval of the president and/or the
board of directors.

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          Section 16.  The assistant treasurer, or if there shall be more than
one, the assistant treasurers in the order determined by the board of directors
(of if there be no such determination, then in the order of their election),
shall, in the absence of the treasurer or in the event of his inability or
refusal to-act, perform the duties and exercise the powers of the treasurer and
shall perform such other duties and have such other powers as the board of
directors may from time to time prescribe.

                                  ARTICLE VI

                             CERTIFICATE OF STOCK

          Section 1.   The shares of a corporation shall be represented by
certificates, provided that the board of directors of the corporation may
provide by resolution or resolutions that some or all of any or all classes or
series of its stock shall be uncertificated shares.  Any such resolution shall
not apply to shares represented by a certificate until such certificate is
surrendered to the corporation.  Notwithstanding the adoption of such a
resolution by the board of directors, every holder of stock represented by
certificates and upon request every holder of uncertified shares shall be
entitled to have a certificate signed by, or in the name of the corporation by
the chairman or vice-chairman of the board of directors, or the president or
vice-president, and by the treasurer or an assistant treasurer, or the secretary
or an assistant secretary of the corporation representing the number of shares
registered in certificate form.

          Section 2.   Any of or all the signatures on the certificate may be
facsimile.  In case any officer, transfer agent or registrar who has signed or
whose facsimile signature has been placed upon a certificate shall have ceased
to be such officer, transfer agent or registrar before

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such certificate is issued, it may be issued by the corporation with the same
effect as if he were such officer, transfer agent or registrar at the date of
issue.

                               LOST CERTIFICATES

          Section 3.  The board of directors may direct a new certificate or
certificates or uncertificated shares to be issued in place of any certificate
or certificates theretofore issued by the corporation alleged to have been lost,
stolen or destroyed, upon the making of an affidavit of that fact by the person
claiming the certificate of stock to be lost, stolen or destroyed.  When
authorizing such issue of a new certificate or certificates or uncertificated
shares, the board of directors may, in its discretion and as a condition
precedent to the issuance thereof, require the owner of such lost, stolen or
destroyed certificate or certificates, or his legal representative, to advertise
the same in such manner as it shall require and/or to give the corporation a
bond in such sum as it may direct as indemnity against any claim that may be
made against the corporation with respect to the certificate alleged to have
been lost, stolen or destroyed.

                               TRANSFER OF STOCK

          Section 4.  Upon surrender to the corporation or the transfer agent of
the corporation of a certificate for shares duly endorsed or accompanied by
proper evidence of succession, assignation or authority to transfer, it shall be
the duty of the corporation to issue a new certificate to the person entitled
thereto, cancel the old certificate and record the transaction upon its books.
The board of directors shall have the power and authority to make all such rules
and regulations as they deem expedient concerning the issuance, transfer and
registration of certificates for the shares of the corporation.

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                              FIXING RECORD DATE

          Section 5.  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 to express consent to corporate action in writing
without a meeting, 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 sixty days prior to any other action.  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 adjourned
meeting.

                            REGISTERED STOCKHOLDERS

          Section 6.  The corporation shall be entitled to recognize the
exclusive right of a person registered on its books as the owner of shares to
receive dividends, and to vote as such owner, and to hold liable for calls and
assessments a person registered on its books as the owner of shares, and shall
not be bound to recognize any equitable or other claim to or interest in such
share or shares on the part of any other person, whether or not it shall have
express or other notice thereof, except as otherwise provided by the laws of
Delaware.

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                                  ARTICLE VII

                              GENERAL PROVISIONS

                                   DIVIDENDS

          Section 1.  Dividends upon the capital stock of the corporation,
subject to the provision of the certificate of incorporation, if any, may be
declared by the board of directors at any regular or special meeting, pursuant
to law.  Dividends may be paid in cash, in property, or in shares of the capital
stock, subject to the provisions of the certificate of incorporation.

          Section 2.  Before payment of any dividend, there may be set aside out
of any funds of the corporation available for dividends such sum or sums as the
directors from time to time, in their absolute discretion, think proper as a
reserve or reserves to meet contingencies, or for equalizing dividends, or for
repairing or maintaining any property of the corporation, or for such other
purpose as the directors shall think conducive to the interest of the
corporation, and the directors may modify or abolish any such reserve in the
manner in which it was created.

                               ANNUAL STATEMENT

          Section 3.  The board of directors shall present at each annual
meeting, and at any special meeting of the stockholders when called for by vote
of the stockholders, a full and clear statement of the business and condition of
the corporation.

                                     CHECKS

          Section 4.  All checks or demands for money and notes of the
corporation shall be signed by such officer or officers or such other person or
persons as the board of directors may from time to time designate.

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                                  FISCAL YEAR

          Section 5.  The fiscal year of the corporation shall be set by the
Board of Directors of the corporation.

                                      SEAL

          Section 6.  The corporate seal shall have inscribed thereon the name
of the corporation, the year of its organization and the words 'Corporate Seal,
Delaware.' The seal may be used by causing it or a facsimile thereof to be
impressed or affixed or reproduced or otherwise.

                                INDEMNIFICATION

          Section 7.  The corporation shall indemnify its officers, directors,
employees and agents to the full extent permitted by the General Corporation Law
of Delaware.

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                                 ARTICLE VIII

                                  AMENDMENTS

          Section 1.  These by-laws may be altered, amended or repealed or new
by-laws may be adopted by the stockholders or by the board of directors, when
such power is conferred upon the board of directors by the certificate of
incorporation at any regular meeting of the stockholders or of the board of
directors or at any special meeting of the stockholders or of the board of
directors if notice of such alteration, amendment, repeal or adoption of new by-
laws be contained in the notice of such special meeting.  If the power to adopt,
amend or repeal by-laws is conferred upon the board of directors by the
certificate of incorporation it shall not divest or limit the power of the
stockholders to adopt, amend or repeal by-laws.

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