Abstract
A single nerve fiber was prepared by the technique of Tasaki from the sciatic nerve of the toad. The proximal trunk of the nerve was stimulated by two successive induction shocks. The action currents were led from the Ranvier's nodes of a single fiber, and recorded by Braun tube oscilloscope. When the interval of the two stimuli was shorter than 2.2 msec., the second stimulus failed to evoke the action current. If the interval was prolonged more than 2.2 msec., there appeared the second small action current. Its conduction velocity was slow. With the prolongation of the interval, the conduction velocity and the strength of the action current were increased. When the interval was increased more than 9.5 msec., the action current evoked by the second stimulus exhibited normal strength and normal conduction velocity. cupermormal velocity of conduction has never been observed in our experiments.
