Russell H. Chittenden

On the Proteolysis of Crystallized Globulin

IT is now a well-established fact that all varieties of proteid matter yield on proteolysis, especially with pepsin-hydrochloric acid, primary and secondary proteoses as well as peptones. There remains, however, much to learn regarding the nature of these bodies, of their relationships, their chemical composition and physiological properties. Especially is it important to be sure of the distinctions between the proteoses as a class and true peptones. We have been inclined in the past to place implicit reliance upon the use of ammonium suilphate as a means of discriminating between these two classes of products, but experience has gradually taught us that the last traces of deuteroproteoses are wont to separate with extreme slowness from a mixture containing proteoses and peptones. No doubt, many preparations of peptones obtained in the past have been contaminated by more or less of this difficultly precipitable proteose, even where conscientious care has been given to all the details of the separation. Years ago the writer called attention to a form of deuterocaseosel which could only be separated by long-continued boiling of the ammonium sulphate-saturated solution. Under such treatment, the caseose gradually separated from the fluid containing it in the form of an oily scum which by proper purification, etc. showed itself to be a genuine deuteroproteose. Quite recently, however, Kiihne2 has showni that complete separation of deuteroproteoses cannot be accomplished by even long-continued boiling of the ainmonium sulphate-saturated solution, unless the reac-