Abstract
It is a essential f act that in the stimulation of a muscle or a single muscle fiber, there is threshold. The author, however, threw a doubt, if the treshold on cathodic contraction of a single muscle fiber would he found or not, and examined on the question in this work.
In the experiment a single fiber separated from M. sartoius etc. of the bullfrog was used. The employed method for stimulaton and recording of the contraction was the same, as was reported by Matsumoto Masao and Satake Y. Thus the author observed the relation between the grade of contraction and the strength of the applied current. The stimulating current wa right angular current or discharge of the condensor.
The result are the following :
With decrease of intelvity, the contraction became smaller and smaller untill it was not observed. This decreasing state of contraction is just like a cury approaching to its asymptote. These states of contraction were observed in cases of all kinds of stimulating current. Considering the results the author confirmed that there was no threshold for cathodic contraotion of the single muscle fiber. But as to the twich of a muscle or a single muscle fiber, of course the confirmation is not applied.
