Advantage was taken of the anti-tryptic effect of blood serum to retard tryptic destruction of insulin given by stomach tube to depancreatized dogs. It was found necessary to supply artificial pancreatic digestion to keep the depancreatized dogs in good condition. Dogs so treated were kept alive 3-4 mo. and at times made to gain in weight by administration of insulin in blood serum by stomach tube. Metabolic and autopsy findings proved the dogs to be completely depancreatized. Ability to utilize carbohydrate was determined by adding a definite amount of dextrose (10-20 gm.) to the blood serum (50-150 cc.) and insulin (40-200 clinical units) mixture and comparing results on R.Q. and D: N with results when blood serum and insulin alone were given. Protocols of 5 dogs are given. Blood sugar changes are less abrupt and not so great as when insulin is given subcutaneously. Possibly the liver protects the body against the shock-like effects of sudden access of insulin to the general circulation. Hypoglycemic shock was never seen following alimentary insulin, even in huge doses. Four dogs were kept alive 81, 125, 41, and 91 days, respectively.