A method has been developed for electrical stimulation of muscles, nerves, and internal organs by means of externally applied electrodes. A miniature germanium rectifier was implanted in experimental animals by surgical means or through a large-gauge hypodermic needle. Subthreshold high-frequency (100 kc) alternating-current pulses were delivered to the skin of the animals. The subthreshold alternating currents spread through the whole body volume, except for a small area around the rectifer''s contact points where half-rectified alternating currents were formed, resulting in elevation of the excitability of the adjacent tissue to its threshold level. This elevation is due to the higher sensitivity of living tissues to unidirectional than to high-frequency alternating currents. Utilizing this method, it was possible to stimulate the sciatic nerve, the hamstring muscles, and myocardium of cats, and the vagus of rats. Respiration could also be maintained in a cat with depressed respiratory center when a rectifier was implanted on the phrenic nerve.