m the male
mandril, whose face, particularly in the breeding season, shows
colored fleshy prominences each side of the nose, with
conspicuous furrows and ridges. In the male mandril these
characters have been developed because, being an unmistakable
sign of sexual ardor, they gave the female particular evidence of
sexual feelings. Thus such characters would come to be recognized
as habitually symptomatic of pleasurable feelings. Finding
similar features in human beings, and particularly in children,
though not developed in the same degree, we may assume that in
our monkey-like ancestors facial characters similar to those of
the mandril were developed, though to a less extent, and that
they were symptomatic of pleasure, because connected with the
period of courtship. Then they became conventionalized as
pleasurable symptoms." (S.S. Buckmann, "Human Babies: What They
Teach," _Nature_, July 5, 1900.) If this view is accepted, it may
be said that the smile, having in man become a generalized sign
of amiability, has no longer any special sexual significance. It
is true that a faint and involuntary smile is often associated
with the later stages of tumescence, but this is usually lost
during detumescence, and may even give place to an expression of
ferocity.

When we have realized how profound is the organic convulsion involved by
the process of detumescence, and how great the general motor excitement
involved, we can understand how it is that very serious effects may follow
coitus. Even in animals this is sometimes the case. Young bulls and
stallions have fallen in a faint after the first congress; boars may be
seriously affected in a similar way; mares have been known even to fall
dead.[125] In the human species, and especially in men--probably, as Bryan
Robinson remarks, because women are protected by the greater slowness with
which detumescence occurs in them--not only death itself, but innumerable
disorders and accidents have been known to follow immediately after
coitus, these results being mainly due to the vascular and muscular
excitement involved by the processes of detumescence. Fainting, vomiting,
urination, defaecation have been noted as occurring in young men after a
first coitus. Epilepsy has been not infrequently recorded. Lesions of
various organs, even rupture of the spleen, have sometimes taken place. In
men of mature age th