Among the roles played by insulin in carbohydrate metabolism, two have been stressed in previous publications from this laboratory.1These roles may be summarized briefly as follows: (1) the control of new sugar formation in the fasting state, taken care of by the basal and (2) the dextrose-disposing mechanism of insulin, operating by oxidation or storage. It has been shown by many observers that the depancreatized dog in the fasting state has a high blood sugar level. The maintenance of a constant normal blood sugar level in the fasting diabetic dog requires the intravenous injection of insulin at the rate of 0.0051 to 0.035 unit per kilogram per hour, as shown by Greeleylaand Houssay.2Evidence that certain patients with severe diabetes may also have a rising blood sugar level in the fasting state has been reported by Martin, Drury and Strouse.1cThey showed that