Electric current as a stimulus, with respect to its duration and strength

Abstract

Our experiments on the excitatory effect of an electric current have been carried out by examining the relation between the current-duration and its liminal strength. From the determination of the optimal electric stimuli of amphibian muscle and nerve by the condenser method (1) (2), and from the investigations on the relation of the current-duration to the liminal current-strength (3) (4), Keith Lucas confirmed that there should exist three substances, at least, in a normal sartorius muscle of frogs and toads; each substance being distinguished by its own “excitation time,” that is, the substance α represents the muscle material, γ the intramuscular nerve material, and β the intermediary substance; the first showing the longest, the second the intermediate, the third the shortest “excitation time.” His further investigations upon the excitatory process (5) (6), led him to confirm the validity of A. V. Hill’s excitation formula in all respects (7) (8). The essential part of our present paper consists of the discussion upon these works. Part I.—Experiments on a Muscle as a Whole. Apparatus and Method of Experiment . On the whole, we adopted Lucas' method (3) with some modifications in detail.