In the history of diabetes numerous theories as to the cause of the disease have been proposed, although no single one has had an anatomic basis definite enough to establish the underlying pathologic process. At present, while the etiology of diabetes is believed by most observers to be due to insufficiency of the internal secretion of the pancreas, yet pathologic anatomists have demonstrated that the kidneys of diabetic patients usually show certain well defined and characteristic lesions.
Armanni1 was the first to point out that in diabetes there was an almost specific injury to the epithelium of the straight tubules by which they lost their cytoplasm and were transformed into hyaline-like vesicles without definite structure. Ebstein2 confirmed this finding and described in coma a typical massing together of necrotic cells. Finally, Ehrlich3 proved that the peculiar hyaline degeneration described by Armanni was due to the deposition of glycogen in the