the powerful reflex contraction of so many of the
voluntary muscles.

"Of course, the foregoing analysis is purely tentative, and I
offer it only on the chance that it may suggest some line of
inquiry which may lead to results of value to the student of
sexual psychology."

In man the whole process of detumescence, when it has once really
begun, only occupies a few moments. It is so likewise in many
animals; in the genera Bos, Ovis, etc., it is very short, almost
instantaneous, and rather short also in the Equidae (in a vigorous
stallion, according to Colin, ten to twelve seconds). As
Disselhorst has pointed out, this is dependent on the fact that
these animals, like man, possess a vas deferens which broadens
into an ampulla serving as a receptacle which holds the semen
ready for instant emission when required. On the other hand, in
the dog, cat, boar, and the Canidae, Felidae, and Suidae generally,
there is no receptacle of this kind, and coitus is slow, since a
longer time is required for the peristaltic action of the vas to
bring the semen to the urogenital sinus. (R. Disselhorst, _Die
Accessorischen Geschlechtsdrusen der Wirbelthiere_, 1897, p.
212.)

In man there can be little doubt that detumescence is more
rapidly accomplished in the European than in the East, in India,
among the yellow races, or in Polynesia. This is probably in part
due to a deliberate attempt to prolong the act in the East, and
in part to a greater nervous erethism among Westerns.

In the woman the specifically sexual muscular process is less visible,
more obscure, more complex, and uncertain. Before detumescence actually
begins there are at intervals involuntary rhythmic contractions of the
walls of the vagina, seeming to have the object of at once stimulating and
harmonizing with those that are about to begin in the male organ. It would
appear that these rhythmic contractions are the exaggeration of a
phenomenon which is normal, just as slight contraction is normal and
constant in the bladder. Jastreboff has shown, in the rabbit, that the
vagina is in constant spontaneous rhythmic contraction from above
downward, not peristaltic, but in segments, the intensity of the
contractions increasing with age and especially with sexual development.
This vaginal contraction which in women only becomes well marked just
before detumescence, and is du