Electrical stimulation of the insular cortex with threshold stimuli produced a fall in blood pressure, inhibition of respiration in expiration, decrease in stomach tonus and inhibition of gastric peristalsis. These responses were not altered in type by varying the wave form, pulse duration or frequency of the stimulating current, although pulse durations of 3-10 msec, and frequencies of 20-100 pulses/see, were most effective. The use of different anesthetics (Dial, Nembutal, ether or chlorolosane-urethane) and retro-gasserian neurectomy did not alter the responses to the stimulation, but gastric responses alone were abolished by sectioning both vagus nerves. Similar responses were obtained by electrical stimulation of the posterior orbital surface and the temporal pole but not by stimulation of the lateral surface of the cerebral hemisphere.