<PAGE>


      As filed with the Securities and Exchange Commission on July 9, 1997
                                               Registration No. 333-______




                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    Form S-8


                             REGISTRATION STATEMENT
                                      Under
                           THE SECURITIES ACT OF 1933

                                Heska Corporation
             (Exact name of registrant as specified in its charter)

                   Delaware                               77-0192527
        ------------------------------                -------------------
       (State or other jurisdiction of                (I.R.S. Employer
        incorporation or organization)                Identification No.)

            1825 Sharp Point Drive
            Fort Collins, Colorado                           80525
        ------------------------------                 ------------------
             (Address of Principal                        (Zip Code)
              Executive Offices)

                 HESKA CORPORATION EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                                                       Copy to:
             FRED M. SCHWARZER                     KAREN A. DEMPSEY
             Heska Corporation                Pillsbury Madison & Sutro LLP
          1825 Sharp Point Drive                   P.O. Box 7880
     Fort Collins, Colorado 80525             San Francisco, CA  94120-7880
              (970) 493-7272                         (415) 983-1000
     ____________________________________    _______________________________
   (Name, address and telephone number,
including area code, of agent for service)

<TABLE>
                         CALCULATION OF REGISTRATION FEE
<CAPTION>
-----------------------------------------------------------------------------------------------------------
    Title of              Amount          Proposed Maximum            Proposed                 Amount of
  Securities To            To Be           Offering Price         Maximum Aggregate          Registration
  Be Registered         Registered          per Share(1)          Offering Price(1)               Fee

-----------------------------------------------------------------------------------------------------------

<S>                   <C>                      <C>                   <C>                         <C>
  Common Stock,       250,000 shares           $8.531                $2,132,750                  $647
 par value $.001
-----------------------------------------------------------------------------------------------------------
</TABLE>


(1)        Estimated in accordance with Rule 457(c) for the purpose of computing
           the amount of the registration fee based on the average of the high
           and low prices of the Company's Common Stock as reported on the
           Nasdaq National Market on July 3, 1997.


                                -----------------


The Registration Statement shall become effective upon filing in accordance with
Rule 462 under the Securities Act of 1933.
________________________________________________________________________________

<PAGE>



                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS


Item 1.  Plan Information.*
______   ________________

Item 2.  Registrant Information and Employee Plan Annual Information.*
______   ___________________________________________________________

                  * Information required by Part I to be contained in the
         Section 10(a) prospectus is omitted from this Registration Statement in
         accordance with Rule 428 under the Securities Act of 1933, as amended,
         and the Note to Part I of Form S-8.


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Certain Documents by Reference.
______   _______________________________________________

                  The following documents filed by Registrant with the
Securities and Exchange Commission are incorporated by reference in this
registration statement:

                  (1) Registrant's prospectus dated June 30, 1997 filed pursuant
to Rule 424(b) under the Securities Act of 1933 (in connection with Registrant's
Registration Statement on Form S-1, File No. 333-25767 (the "Form S-1
Registration Statement")), which contains the balance sheets of the Registrant
as of December 31, 1995 and 1996 and March 31, 1997 (unaudited) and the related
statements of operations, stockholders' equity and cash flows for each of the
three years in the period ended December 31, 1994, 1995 and 1996 and the three
months ended March 31, 1997 (unaudited), together with the report thereon of
Arthur Andersen LLP, independent public accountants, and the statements of
income and cash flows of Diamond Animal Health, Inc., for the years ended March
31, 1995 and 1996, together with the reports thereon of Ernst & Young LLP and
McGladrey & Pullen, LLP, independent public accountants.

                  (2) The description of Registrant's Common Stock contained in
Registrant's registration statement on Form 8-A, filed April 24, 1997.

                  In addition, all documents subsequently filed by Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934, prior to the filing of a post-effective amendment which indicates that
all securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference in this
registration statement and to be a part hereof from the date of filing of such
documents.



                                       -2-

<PAGE>

Item 4.  Description of Securities.
______   _________________________

         Not applicable.

Item 5.  Interests of Named Experts and Counsel.
______   ______________________________________

         The financial statements of Heska Corporation incorporated by
reference in this registration statement have been audited by Arthur Andersen
LLP, independent public accountants, and the financial statements of Diamond
Animal Health, Inc. incorporated by reference in this registration statement
have been audited by McGladrey & Pullen, LLP and Ernst & Young LLP, independent
public accountants, to the extent indicated in each of their reports thereon
also incorporated by reference. Such financial statements have been incorporated
herein by reference in reliance upon each of such reports given upon the
authority of said firms as experts in auditing and accounting.


Item 6.  Indemnification of Directors and Officers.
______   _________________________________________

         Section 145 of the Delaware General Corporation Law provides
for the indemnification of officers, directors, and other corporate agents in
terms sufficiently broad to indemnify such persons under certain circumstances
for liabilities (including reimbursement for expenses incurred) arising under
the Securities Act of 1933, as amended (the "Act"). Article XI of the
Registrant's Restated Certificate of Incorporation (Exhibit 3.1(c) to the Form
S-1 Registration Statement) provides for indemnification of the Registrant's
directors, officers, employees and other agents to the extent and under the
circumstances permitted by the Delaware General Corporation Law.

        The Underwriting Agreement (Exhibit 1.1 to the Form S-1
Registration Statement) provides for indemnification by the Underwriters of the
Registrant, its directors and officers, and by the Registrant of the
Underwriters, for certain liabilities, including liabilities arising under the
Act, and affords certain rights of contribution with respect thereto.

        The Company has entered into separate indemnification
agreements (a form of which has been filed as Exhibit 10.18 to the Form S-1
Registration Statement) with each of its directors and certain of its executive
officers that will require the Company, among other things, to indemnify them
against certain liabilities that may arise by reason of their status or service
as a director or executive officer, as the case may be, to the fullest extent
not prohibited by law.


Item 7.  Exemption from Registration Claimed.
______   ___________________________________

         Not applicable.



                                       -3-

<PAGE>

Item 8.  Exhibits.
______   ________

         See Index to Exhibits.

Item 9.  Undertakings.
______   ____________

         (a)     The undersigned Registrant hereby undertakes:

                 (1) To file, during any period in which offers or
         sales are being made, a post-effective amendment to this registration
         statement:

                      (i)     To include any prospectus required by
                  section 10(a)(3) of the Securities Act of 1933;

                      (ii) To reflect in the prospectus any facts
                  or events arising after the effective date of the
                  post-registration statement (or the most recent effective
                  amendment thereof) which, individually or in the aggregate,
                  represent a fundamental change in the information set forth in
                  the registration statement;

                      (iii) To include any material information
                  with respect to the plan of distribution not previously
                  disclosed in the registration statement or any material change
                  to such information in the registration statement;

         provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
         apply if the registration statement is on Form S-3 or Form S-8, and the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed by the
         Registrant pursuant to section 13 or section 15(d) of the Securities
         Exchange Act of 1934 that are incorporated by reference in the
         registration statement.

                    (2) That, for the purpose of determining any
         liability under the Securities Act of 1933, each such post-effective
         amendment shall be deemed to be a new registration statement relating
         to the securities offered therein, and the offering of such securities
         at that time shall be deemed to be the initial bona fide offering
         thereof.

                    (3) To remove from registration by means of a
         post-effective amendment any of the securities being registered which
         remain unsold at the termination of the offering.

         (b) The undersigned Registrant hereby further undertakes that,
for purposes of determining any liability under the Securities Act of 1933, each
filing of the Registrant's annual report pursuant to section 13(a) or section
15(d) of the Securities Exchange Act of 1934


                                       -4-

<PAGE>

that is incorporated by reference in the registration statement shall be deemed
to be a new registration statement relating to the securities offered therein,
and the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

        (c) Insofar as indemnification for liabilities arising under
the Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the Registrant pursuant to the foregoing provisions, or
otherwise, the Registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.


                                       -5-

<PAGE>

                                   SIGNATURES

             Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8, and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Fort Collins, State of Colorado, on July 7,
1997.

                                       HESKA CORPORATION


                                  By      /s/FRED M. SCHWARZER
                                        _____________________________________
                                             Fred M. Schwarzer
                                        President and Chief Executive Officer


                                POWER OF ATTORNEY
                                -----------------

             KNOW ALL MEN BY THESE PRESENTS, that each person whose
signature appears below constitutes and appoints Fred M. Schwarzer, Robert B.
Grieve, William G. Skolout and Deborah E. Robbins, and each of them his or her
true and lawful attorneys-in-fact and agents, each with full power of
substitution and resubstitution, for him or her and in his or her name, place
and stead, in any and all capacities, to sign any and all amendments, including
post-effective amendments, to this registration statement, and to file the same,
with exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, full power and authority to do and perform each and every act and thing
requisite and necessary to be done, as fully to all intents and purposes as he
or she might or could do in person, hereby ratifying and confirming all that
said attorneys-in-fact and agents, or his or her substitute or substitutes, may
do or cause to be done by virtue hereof.

             Pursuant to the requirements of the Securities Act of 1933,
this registration statement has been signed by the following persons in the
capacities and on the date indicated:

         Name                 Title                              Date


/s/ FRED M. SCHWARZER         President and Chief                July 7, 1997
________________________      Executive Officer
    Fred M. Schwarzer         (Pincipal Executive Officer)
                              and Director 


/s/ WILLIAM G. SKOLOUT        Chief Financial Officer (Principal July 7, 1997
_________________________     Financial Officer and Accounting  
    William G. Skolout        Officer)                          
                              

<PAGE>

/s/ A. BARR DOLAN                  Chairman of the Board     July 7, 1997
_____________________________
    A. Barr Dolan


/s/ ROBERT B. GRIEVE, PH.D.        Chief Scientific Officer  July 7, 1997
_____________________________      and Vice Chairman            
    Robert B. Grieve, Ph.D.                                    


/s/ LYLE A. HOHNKE, PH.D.          Director                  July 7, 1997
_____________________________
    Lyle A. Hohnke, Ph.D.


/s/ DENIS H. POMROY                Director                  July 7, 1997
_____________________________
    Denis H. Pomroy


/s/ LYNNOR B. STEVENSON, PH.D.     Director                  July 7, 1997
______________________________
    Lynnor B. Stevenson, Ph.D.


/s/ GUY TEBBIT, Ph.D.              Director                  July 7, 1997
______________________________
    Guy Tebbit, Ph.D.

<PAGE>

                                INDEX TO EXHIBITS


Exhibit
Number                Exhibit
_______               _______

4.1*                  Specimen Common Stock Certificate

5.1                   Opinion regarding legality of
                      securities to be offered.

23.1                  Consent of Arthur Andersen LLP.

23.2                  Consent of McGladrey & Pullen, LLP.

23.3                  Consent of Ernst & Young LLP.

23.4                  Consent of Pillsbury Madison &
                      Sutro LLP (included in Exhibit 5.1).

24.1                  Power of Attorney (included on page 6).

--------
*    Incorporated by reference to Exhibit 4.1 to Registrant's Registration
Statement on Form S-1, File No. 333-25767.
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 16948}]
{"company-data": {"conformed-name": "HESKA CORP", "cik": "0001038133", "assigned-sic": "2836", "irs-number": "770192527", "state-of-incorporation": "CA", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-30951", "film-number": "97638066"}, "business-address": {"street1": "1825 SHARP POINT DR", "city": "FORT COLLINS", "state": "CO", "zip": "80525", "phone": "9704937272"}, "mail-address": {"street1": "1825 SHARP POINT DR", "city": "FORT COLLINS", "state": "CO", "zip": "80525"}}
As filed with the Securities and Exchange Commission on July 9, 1997
                                               Registration No. 333-______

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    Form S-8

                             REGISTRATION STATEMENT
                                      Under
                           THE SECURITIES ACT OF 1933

                                Heska Corporation
             (Exact name of registrant as specified in its charter)

                   Delaware                               77-0192527
        ------------------------------                -------------------
       (State or other jurisdiction of                (I.R.S. Employer
        incorporation or organization)                Identification No.)

            1825 Sharp Point Drive
            Fort Collins, Colorado                           80525
        ------------------------------                 ------------------
             (Address of Principal                        (Zip Code)
              Executive Offices)

                 HESKA CORPORATION EMPLOYEE STOCK PURCHASE PLAN
                            (Full title of the plan)

                                                       Copy to:
             FRED M. SCHWARZER                     KAREN A. DEMPSEY
             Heska Corporation                Pillsbury Madison & Sutro LLP
          1825 Sharp Point Drive                   P.O. Box 7880
     Fort Collins, Colorado 80525             San Francisco, CA  94120-7880
              (970) 493-7272                         (415) 983-1000
     ____________________________________    _______________________________
   (Name, address and telephone number,
including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------
    Title of              Amount          Proposed Maximum            Proposed                 Amount of
  Securities To            To Be           Offering Price         Maximum Aggregate          Registration
  Be Registered         Registered          per Share(1)          Offering Price(1)               Fee

-----------------------------------------------------------------------------------------------------------
Common Stock,       250,000 shares           $8.531                $2,132,750                  $647
 par value $.001
-----------------------------------------------------------------------------------------------------------
(1)        Estimated in accordance with Rule 457(c) for the purpose of computing
           the amount of the registration fee based on the average of the high
           and low prices of the Company's Common Stock as reported on the
           Nasdaq National Market on July 3, 1997.

                                -----------------

The Registration Statement shall become effective upon filing in accordance with
Rule 462 under the Securities Act of 1933.
________________________________________________________________________________
PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1.  Plan Information.*
______   ________________

Item 2.  Registrant Information and Employee Plan Annual Information.*
______   ___________________________________________________________

                  * Information required by Part I to be contained in the
         Section 10(a) prospectus is omitted from this Registration Statement in
         accordance with Rule 428 under the Securities Act of 1933, as amended,
         and the Note to Part I of Form S-8.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Certain Documents by Reference.
______   _______________________________________________

                  The following documents filed by Registrant with the
Securities and Exchange Commission are incorporated by reference in this
registration statement:

                  (1) Registrant's prospectus dated June 30, 1997 filed pursuant
to Rule 424(b) under the Securities Act of 1933 (in connection with Registrant's
Registration Statement on Form S-1, File No. 333-25767 (the "Form S-1
Registration Statement")), which contains the balance sheets of the Registrant
as of December 31, 1995 and 1996 and March 31, 1997 (unaudited) and the related
statements of operations, stockholders' equity and cash flows for each of the
three years in the period ended December 31, 1994, 1995 and 1996 and the three
months ended March 31, 1997 (unaudited), together with the report thereon of
Arthur Andersen LLP, independent public accountants, and the statements of
income and cash flows of Diamond Animal Health, Inc., for the years ended March
31, 1995 and 1996, together with the reports thereon of Ernst & Young LLP and
McGladrey & Pullen, LLP, independent public accountants.

                  (2) The description of Registrant's Common Stock contained in
Registrant's registration statement on Form 8-A, filed April 24, 1997.

                  In addition, all documents subsequently filed by Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act
of 1934, prior to the filing of a post-effective amendment which indicates that
all securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated by reference in this
registration statement and to be a part hereof from the date of filing of such
documents.

                                       -2-
Item 4.  Description of Securities.
______   _________________________

         Not applicable.

Item 5.  Interests of Named Experts and Counsel.
______   ______________________________________

         The financial statements of Heska Corporation incorporated by
reference in this registration statement have been audited by Arthur Andersen
LLP, independent public accountants, and the financial statements of Diamond
Animal Health, Inc. incorporated by reference in this registration statement
have been audited by McGladrey & Pullen, LLP and Ernst & Young LLP, independent
public accountants, to the extent indicated in each of their reports thereon
also incorporated by reference. Such financial statements have been incorporated
herein by reference in reliance upon each of such reports given upon the
authority of said firms as experts in auditing and accounting.

Item 6.  Indemnification of Directors and Officers.
______   _________________________________________

         Section 145 of the Delaware General Corporation Law provides
for the indemnification of officers, directors, and other corporate agents in
terms sufficiently broad to indemnify such persons under certain circumstances
for liabilities (including reimbursement for expenses incurred) arising under
the Securities Act of 1933, as amended (the "Act"). Article XI of the
Registrant's Restated Certificate of Incorporation (Exhibit 3.1(c) to the Form
S-1 Registration Statement) provides for indemnification of the Registrant's
directors, officers, employees and other agents to the extent and under the
circumstances permitted by the Delaware General Corporation Law.

        The Underwriting Agreement (Exhibit 1.1 to the Form S-1
Registration Statement) provides for indemnification by the Underwriters of the
Registrant, its directors and officers, and by the Registrant of the
Underwriters, for certain liabilities, including liabilities arising under the
Act, and affords certain rights of contribution with respect thereto.

        The Company has entered into separate indemnification
agreements (a form of which has been filed as Exhibit 10.18 to the Form S-1
Registration Statement) with each of its directors and certain of its executive
officers that will require the Company, among other things, to indemnify them
against certain liabilities that may arise by reason of their status or service
as a director or executive officer, as the case may be, to the fullest extent
not prohibited by law.

Item 7.  Exemption from Registration Claimed.
______   ___________________________________

         Not applicable.

                                       -3-
Item 8.  Exhibits.
______   ________

         See Index to Exhibits.

Item 9.  Undertakings.
______   ____________

         (a)     The undersigned Registrant hereby undertakes:

                 (1) To file, during any period in which offers or
         sales are being made, a post-effective amendment to this registration
         statement:

                      (i)     To include any prospectus required by
                  section 10(a)(3) of the Securities Act of 1933;

                      (ii) To reflect in the prospectus any facts
                  or events arising after the effective date of the
                  post-registration statement (or the most recent effective
                  amendment thereof) which, individually or in the aggregate,
                  represent a fundamental change in the information set forth in
                  the registration statement;

                      (iii) To include any material information
                  with respect to the plan of distribution not previously
                  disclosed in the registration statement or any material change
                  to such information in the registration statement;

         provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
         apply if the registration statement is on Form S-3 or Form S-8, and the
         information required to be included in a post-effective amendment by
         those paragraphs is contained in periodic reports filed by the
         Registrant pursuant to section 13 or section 15(d) of the Securities
         Exchange Act of 1934 that are incorporated by reference in the
         registration statement.

                    (2) That, for the purpose of determining any
         liability under the Securities Act of 1933, each such post-effective
         amendment shall be deemed to be a new registration statement relating
         to the securities offered therein, and the offering of such securities
         at that time shall be deemed to be the initial bona fide offering
         thereof.

                    (3) To remove from registration by means of a
         post-effective amendment any of the securities being registered which
         remain unsold at the termination of the offering.

         (b) The undersigned Registrant hereby further undertakes that,
for purposes of determining any liability under the Securities Act of 1933, each
filing of the Registrant's annual report pursuant to section 13(a) or section
15(d) of the Securities Exchange Act of 1934

                                       -4-
that is incorporated by reference in the registration statement shall be deemed
to be a new registration statement relating to the securities offered therein,
and the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

        (c) Insofar as indemnification for liabilities arising under
the Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the Registrant pursuant to the foregoing provisions, or
otherwise, the Registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Act and is, therefore, unenforceable. In the event that a claim
for indemnification against such liabilities (other than the payment by the
Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the Registrant will, unless in
the opinion of its counsel the matter has been settled by controlling precedent,
submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.

                                       -5-
SIGNATURES

             Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8, and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Fort Collins, State of Colorado, on July 7,
1997.

                                       HESKA CORPORATION

                                  By      /s/FRED M. SCHWARZER
                                        _____________________________________
                                             Fred M. Schwarzer
                                        President and Chief Executive Officer

                                POWER OF ATTORNEY
                                -----------------

             KNOW ALL MEN BY THESE PRESENTS, that each person whose
signature appears below constitutes and appoints Fred M. Schwarzer, Robert B.
Grieve, William G. Skolout and Deborah E. Robbins, and each of them his or her
true and lawful attorneys-in-fact and agents, each with full power of
substitution and resubstitution, for him or her and in his or her name, place
and stead, in any and all capacities, to sign any and all amendments, including
post-effective amendments, to this registration statement, and to file the same,
with exhibits thereto and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, full power and authority to do and perform each and every act and thing
requisite and necessary to be done, as fully to all intents and purposes as he
or she might or could do in person, hereby ratifying and confirming all that
said attorneys-in-fact and agents, or his or her substitute or substitutes, may
do or cause to be done by virtue hereof.

             Pursuant to the requirements of the Securities Act of 1933,
this registration statement has been signed by the following persons in the
capacities and on the date indicated:

         Name                 Title                              Date

/s/ FRED M. SCHWARZER         President and Chief                July 7, 1997
________________________      Executive Officer
    Fred M. Schwarzer         (Pincipal Executive Officer)
                              and Director 

/s/ WILLIAM G. SKOLOUT        Chief Financial Officer (Principal July 7, 1997
_________________________     Financial Officer and Accounting  
    William G. Skolout        Officer)
/s/ A. BARR DOLAN                  Chairman of the Board     July 7, 1997
_____________________________
    A. Barr Dolan

/s/ ROBERT B. GRIEVE, PH.D.        Chief Scientific Officer  July 7, 1997
_____________________________      and Vice Chairman            
    Robert B. Grieve, Ph.D.                                    

/s/ LYLE A. HOHNKE, PH.D.          Director                  July 7, 1997
_____________________________
    Lyle A. Hohnke, Ph.D.

/s/ DENIS H. POMROY                Director                  July 7, 1997
_____________________________
    Denis H. Pomroy

/s/ LYNNOR B. STEVENSON, PH.D.     Director                  July 7, 1997
______________________________
    Lynnor B. Stevenson, Ph.D.

/s/ GUY TEBBIT, Ph.D.              Director                  July 7, 1997
______________________________
    Guy Tebbit, Ph.D.
INDEX TO EXHIBITS

Exhibit
Number                Exhibit
_______               _______

4.1*                  Specimen Common Stock Certificate

5.1                   Opinion regarding legality of
                      securities to be offered.

23.1                  Consent of Arthur Andersen LLP.

23.2                  Consent of McGladrey & Pullen, LLP.

23.3                  Consent of Ernst & Young LLP.

23.4                  Consent of Pillsbury Madison &
                      Sutro LLP (included in Exhibit 5.1).

24.1                  Power of Attorney (included on page 6).

--------
*    Incorporated by reference to Exhibit 4.1 to Registrant's Registration
Statement on Form S-1, File No. 333-25767.