a moment, vibrating, and then all resistance is withdrawn by a sudden ‘flashing open’ of the gates, permitting easy entrance, and that the sudden giving up of resistance, and substitution of welcome, with its instantaneous deep entrance, causes an almost immediate male orgasm (the thrill being irresistibly exciting).  Certainly this is the process as observed in horses, cattle, goats, etc., and it seems likely something analogous is natural in man.”

While it is easily possible to carry to excess a view which would make the woman rather than the man the active agent in coitus (and it may be recalled that in the Cebidae the penis, as also the clitoris, is furnished with a bone), there is probably an element of truth in the belief that the vagina shares in the active part which, there can now be little doubt, is played by the uterus in detumescence.  Such a view certainly enables us to understand how it is that semen effused on the exterior sexual organs can be conveyed to the uterus.

It was indeed the failure to understand the vital activity of the semen and the feminine genital canal, co-operating together towards the junction of sperm cell and germ cell, which for so long stood in the way of the proper understanding of conception.  Even the genius of Harvey, which had grappled successfully with the problem of the circulation, failed in the attempt to comprehend the problem of generation.  Mainly on account of this difficulty, he was unable to see how the male element could possibly enter the uterus, although he devoted much observation and study to the question.  Writing of the uterus of the doe after copulation, he says:  “I began to doubt, to ask myself whether the semen of the male could by any possibility make its way by attraction or injection to the seat of conception, and repeated examination led me to the conclusion that none of the semen reached this seat.” (De-Generatione Animalium, Exercise lxvii.) “The woman,” he finally concluded, “after contact with the spermatic fluid in coitu, seems to receive an influence and become fecundated without the co-operation of any sensible corporeal agent, in the same way as iron touched by the magnet is endowed with its powers.”

Although the specifically sexual muscular process of detumescence in women—­as distinguished from the general muscular phenomena of sexual excitement which may be fairly obvious—­is thus seen to be somewhat complex and obscure, in women as well as in men detumescence is a convulsion which discharges a slowly accumulated store of nervous force.  In women also, as in men, the motor discharge is directed to a specific end—­the intromission of the semen in the one sex, its reception in the other.  In both sexes the sexual orgasm and the pleasure and satisfaction associated with it, involve, as their most essential element, the motor activity of the sexual sphere.[121]