Brunschwig et al.(1943) and Bailey and Bailey (1943) first reported the inducement of a pancreatic state in animals by the injection of alloxan. Soon after the cytotoxic effects of alloxan on the pancreatic islets had been disclosed by Dunn et al.(1943), many of such substances capable of selectively destructing the B-cells have been found. But among them, dithizone and oxine (or its derivatives), which were found by Okamoto et al.(Okamoto, 1949), merit special attention from the viewpoint of their diabetogenic capacity.