I. INTRODUCTION
The earlier trials, both laboratory and clinical, of pancreatic opotherapy, were conceived and undertaken at a time when the ground-problems of diabetes — almost coextensive as they are with the whole domain of pathometabolism — were not so clearly defined as at present. Nevertheless, on historical consideration of these attempts it becomes obvious that the propelling forces behind them all were, first, the urgent demand for a successful therapy, and, following that, the vague assumption, dating from or even antedating von Mering and Minkowski's classic work, that the pathogenetic basis of the clinical entity diabetes is the absence or deficiency of a pancreatic hormone or internal secretion necessary in some sense to carbohydrate utilization. Whether this basal assumption of an internal secretion shall prove valid or not, it is certain that the attempts at pancreatic organotherapy have amply justified themselves, not as yet by realizing