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 before puberty the voice retains its childlike qualities.[116]

As a matter of fact, I believe that we may attach a considerable degree of importance to the voice and to music generally as a method of sexual appeal.  On this point I agree with Moll, who remarks that “the sense of hearing here plays a considerable part, and the stimulation received through the ears is much larger than is usually believed."[117] I am not, however, inclined to think that this influence is considerable in its action on men, although Mantegazza remarks, doubtless with a certain truth, that “some women’s voices cannot be heard with impunity.”  It is true that the ancients deprecated the sexual or at all events the effeminating influence of some kinds of music, but they seem to have regarded it as sedative rather than stimulating; the kind of music they approved of as martial and stimulating was the kind most likely to have sexual effects in predisposed persons.

The Chinese and the Greeks have more especially insisted on the ethical qualities of music and on its moralizing and demoralizing effects.  Some three thousand years ago, it is stated, a Chinese emperor, believing that only they who understood music are capable of governing, distributed administrative functions in accordance with this belief.  He acted entirely in accordance with Chinese morality, the texts of Confucianism (see translations in the “Sacred Books of the East Series”) show clearly that music and ceremony (or social ritual in a wide sense) are regarded as the two main guiding influences of life—­music as the internal guide, ceremony as the external guide, the former being looked upon as the more important.

Among the Greeks Menander said that to many people music is a powerful stimulant to love.  Plato, in the third book of the Republic, discusses what kinds of music should be encouraged in his ideal state.  He does not clearly state that music is ever a sexual stimulant, but he