1952 年 43 巻 2 号 p. 52-54
1) I have described the appearance of the motion of the sphincter ani muscle by ejaculation in curves on the kymographion in 5 cases. 2) According to the curves described, it was noticed that there were much individual variations (rhythmic movement) in casting out the semens. 3) From these curves it is also concluded that the ejaculation is only a reflex motion and the maximum agitation of the muscle occurs continuously ending when the muscle is too exhausted to agitate even though the stimulation is still given continuously from the spinal center. 4) It is considered, to my belief, that the action of the spincter ani muscle by ejaculation resembles that of the same seen in terminal dribble, which action is occured with the correlation of the bulbocavernous muscle and the ishiocavernous muscle. The only difference seen in both movements, ejaculation and terminal dribble, is that while the former is only a reflex motion, the latter is a rather voluntary motion. 5) Future problems concerning ejaculation rising from this experiment were discussed.