he sexual impulse is dependent on the need of evacuation. Professor
Tarchanoff, of St. Petersburg, however, made an experiment which seemed to
be crucial. He took several hundred frogs (_Rana temporaria_), nearly all
in the act of coitus, and in the first place repeated Goltz's experiments.
He removed the heart; but this led to no direct or indirect stoppage of
coitus, nor did removal of the lungs, parts of the liver, the spleen, the
intestines, the stomach, or the kidneys. In the same way even careful
removal of both testicles had no result. But on removing the seminal
receptacles coitus was immediately or very shortly stopped, and not
renewed. Thus, Tarchanoff concluded that in frogs, and possibly therefore
in mammals, the seminal receptacles are the starting-point of the
centripetal impulse which by reflex action sets in motion the complicated
apparatus of sexual activity.[5] A few years later the question was again
taken up by Steinach, of Prague. Granting that Tarchanoff's experiments
are reliable as regards the frog, Steinach points out that we may still
ask whether in mammals the integrity of the seminal receptacles is bound
up with the preservation of sexual excitability. This cannot be taken for
granted, nor can we assume that the seminal receptacles of the frog are
homologous with the seminal vesicles of mammals. In order to test the
question, Steinach chose the white rat, as possessing large seminal
vesicles and a very developed sexual impulse. He found that removal of the
seminal sacs led to no decrease in the intensity of the sexual impulse;
the sexual act was still repeated with the same frequency and the same
vigor. But these receptacles, Steinach proceeded to argue, do not really
contain semen, but a special secretion of their own; they are anatomically
quite unlike the seminal receptacles of the frog; so that no doubt is thus
thrown on Tarchanoff's observations. Steinach remarked, however, that
one's faith is rather shaken by the fact that in the _Esculenta_, which
in sexual life closely resembles _Rana temporaria_, there are no seminal
receptacles. He therefore repeated Tarchanoff's experiments, and found
that the seminal receptacles were empty before coitus, only becoming
gradually filled during coitus; it could not, therefore, be argued that
the sexual impulse started from the receptacles. He then extirpated the
seminal receptacles, avoiding hemorrhage as far as possible, and found
that, in the majority