SOME CHEMICAL REACTIONS OF THE SUBSTANCE CONTAIiVING INSULIN.*

The pancreatic substance containing insulin1 used in the experiments recorded below was prepared from the pancreas of hogs according to the method developed2 by Mr. George B. Walden of the Lilly Research Laboratories, and which has been published by the Council of Pharmacy and Chemistry of the American Medical Association.3 This experiment, which is an extension of Mr. Walden’s work, was started at the suggestion of Dr. G. H. A. Clowes with the hope of isolating the physiologically active substance as a compound possessing a definite chemical constitution, or at least of determining some characteristic react,ion peculiar to the active principle. Though neither of these results has been achieved it was thought that the somewhat disconnected data secured might be of interest. A solution of insulin, thus prepared, gives almost all the protein tests, and consists chiefly of proteoses, together with some peptones, peptides, and amino-acids. Different lots prepared