Iowa State University Veterinarian Records, RS 22/6/0/9, University Archives, Special Collections Department, Iowa State University, http://www.add.lib.iastate.edu/spcl/arch/rgrp/22-6-0-9.html
Enzymes, or ferments as they were known in earlier times, have been used in medicine for centuries. From the time of Pasteur interest in enzymes has increased till, at the present date, we have active research groups devoting much time and money to the study of the nature and applied uses of a great variety of enzymes.
Huffman, Earl F.
"The Nature and Applications of Tryptic Enzymes in Veterinary Practice,"
Iowa State University Veterinarian: Vol. 20
, Article 1.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol20/iss1/1