Since the discovery of insulin the treatment of diabetes mellitus has made remarkable strides. Many factors underlying the causation of the disease, however, remain obscure. The associated anatomic changes are for the most part the result of an excess amount of sugar in the blood and are thus the effects rather than the causes of the disease. It is true that changes in the pancreas occur with great frequency, but these are not constant. In a study of 229 diabetic patients Warren1anoted that the pancreas showed fibrosis, hyaline degeneration, hypertrophy, hydropic degeneration, pyknotic nuclei, hemorrhage or adenoma in the islands of Langerhans in 190 patients while in 69 patients it was normal. The author1bstated: These cases in which changes in the pancreas are absent or too trifling to merit consideration have always puzzled and irritated the pathologist. It is difficult to conceive of long-continued and profound