On the Almost Instantaneous Transport of Spermatozoa Through the Cervix and the Uterus in the Rat.

Abstract

It is almost universally believed that spermatozoa owe their progression through the female genital tract to the lashing of their vibratile tails. Elaborate experiments have been made testing the rate of progression of spermatozoa in salt solution under the microscope, their chemotaxis towards uterine, tubal and ovarian tissue, their negative rheotropism towards a ciliary stream, the time elapsing between copulation and the appearance of sperms at the fimbriated end of the tube. (Bischoff.)∗

Since the uterine horns of laboratory rodents as well as other mammals are filled to turgidity with fluid at the time of oestrus, it seemed logical to try to determine whether the uterine fluid also functioned as a readily miscible matrix for the rapid transport of the semen by uterine contraction.

Preliminary experiments were made by the senior writer in the laboratory of Dr. Herbert M. Evans, which led to no definite conclusions because of the difficulty of determining the exact instant of ejaculation. In the same laboratory, the junior writer observed and learned to interpret the behavior of the male so as almost infallibly to diagnose the copulation that resulted in ejaculation, which made the present study possible. Thanks are due Dr. Evans for the use of the facilities of his rat colony and to Dr. R. R. Squier for assistance in the present series of experiments. The results are striking and at variance with the general notion, yet clear-cut and conclusive.†