EXHIBIT 10.19 Dr. Ralph W.F. Hardy 330 The Parkway Ithaca, NY 14850 Dear Dr. Hardy: By this letter agreement, BioTechnica would like to amend your Consulting Agreement dated January 8, 1996, as follows: 2. Term; Payment Upon Termination (a) The term of this Agreement shall commence on January 1, 1997, and shall terminate on the earlier of the death of the Consultant or on December 31, 1997 (the "Expiration Date"). If the provisions of this letter are in accordance with your understanding, please sign and return one of the enclosed copies. Very truly yours, /s/ Bruno Carette President and Chief Operating Officer Acknowledged and Agreed by: /s/ Ralph W.F. Hardy Dec. 4, 1996 Ralph W.F. Hardy Date