A technique for subtotal pancreatec-tomy in toads was devised following which there developed a prolonged state of diabetes, when the operation was performed during the winter season; during the summer mos. the blood sugar returned to its normal level due to the regeneration of the remaining pancreatic tissue. The advantage of this method of subtotal over total pancreatec-tomy is evident since there is no interference with the systemic circulation and the animals may survive for as long as 40 days. Simultaneous removal of the ant. lobe of the hypophysis prevented the appearance of pancreatic diabetes, while subsequent inj. of ant. pituitary tissue provoked hyperglycemia. Ant. pituitary tissue did not produce hyperglycemia in intact toads showing that in this sp., unlike the dog, the pancreas was strongly antidiabeto-genic. Adrenalectomy also attenuated the state of pancreatic diabetes, and the latter could be made to reappear upon the injn. of ant. pituitary lobes. Extirpation of the thyroid in no way modifies the production of pancreatic diabetes.