1. In a group of 13 schizophrenic patients the blood sugar fell more promptly in response to coma doses of amorphous insulin given intravenously than to those given subcutaneously.2. The fall in blood sugar in response to coma doses of insulin given intravenously occurs at about the same rate as in response to small doses—e.g., 10 units. In the latter case the blood sugar returns to normal values rapidly, whereas in the former it stays low for a prolonged time, so that coma ensues.3. The only practical advantage of the intravenous administration of insulin is the shortening of the pre-coma period.4. There was no appreciable difference in the coma doses required between the two methods of administration.5. There was no significant difference in the complications resulting from the two methods of injection.6. Spontaneous emergence from coma produced by intravenous insulin is rare.Abstract Teaser