Protamine Zinc Insulin

A remarkable step forward in insulin therapy was achieved by Hagedorn1when he discovered protamine insulin. The addition of zinc to protamine insulin was suggested by Scott and Fisher;2zinc further enhances the prolonged action of protamine insulin and renders the mixture stable for a period of at least six months. Protamine zinc insulin is the only protamine insulin combination obtainable today. Protamine zinc insulin in many cases lowers the blood sugar for much more than twenty-four hours,3while protamine insulin acts for only twelve to fourteen hours. Consequently the observations made with protamine insulin, splendid as they have been, are not applicable to the management of diabetes with protamine zinc insulin, and to a great extent new plans of treatment must be developed. The diabetic cases observed have been derived mainly from three sources: First, a series of thirty-seven cases at Sea View Hospital. This is a