it is the performance of the male that attracts the female; it is
only among very simple and primitive musicians, like some insects, that
the female thus attracts the male.[113] The fact that it is nearly always
one sex only that is thus musically gifted should alone have sufficed to
throw suspicion on any but a sexual solution of this problem of animal
song.

It is, however, an exceedingly remarkable fact that, although among
insects and lower vertebrates the sexual influence of music is so large,
and although among mammals and predominantly in man the emotional and
aesthetic influence of music is so great, yet neither in man nor any of the
higher mammals has music been found to exert a predominant sexual
influence, or even in most cases any influence at all. Darwin, while
calling attention to the fact that the males of most species of mammals
use their vocal powers chiefly, and sometimes exclusively, during the
breeding-season, adds that "it is a surprising fact that we have not as
yet any good evidence that these organs are used by male mammals to charm
the female."[114] From a very different standpoint, Fere, in studying the
pathology of the human sexual instinct in the light of a very full
knowledge of the available evidence, states that he knows of no detailed
observations showing the existence of any morbid sexual perversions based
on the sense of hearing, either in reference to the human voice or to
instrumental music.[115]

When, however, we consider that not only in the animals most nearly
related to man, but in man himself, the larynx and the voice undergo a
marked sexual differentiation at puberty, it is difficult not to believe
that this change has an influence on sexual selection and sexual
psychology. At puberty there is a slight hyperaemia of the larynx,
accompanied by rapid development alike of the larynx itself and of the
vocal cords, which become larger and thicker, while there is an associated
change in the voice, which deepens. All these changes are very slight in
girls, but very pronounced in boys, whose voices are said to "break" and
then become lower by at least an octave. The feminine larynx at puberty
only increases in the proportion of 5 to 7, but the masculine larynx in
the proportion of 5 to 10. The direct dependence of this change on the
general sexual development is shown not merely by its occurrence at
puberty, but by the fact that in eunuchs in whom the testicles have been
removed befo