The Descent of Man

herited this difference from his early progenitors.
His vocal cords are about one-third longer
than in woman, or than in boys; and emasculation
produces the same effect on him as on the
lower animals, for it "arrests that prominent
growth of the thyroid, etc., which accompanies
the elongation of the cords." (27. Owen, 'Anatomy
of Vertebrates,' vol. iii. p. 603.) With respect
to the cause of this difference between the
sexes, I have nothing to add to the remarks in
the last chapter on the probable effects of the
long-continued use of the vocal organs by the
male under the excitement of love, rage and
jealousy. According to Sir Duncan Gibb (28.
'Journal of the Anthropological Society,' April
1869, p. lvii. and lxvi.), the voice and the form
of the larynx differ in the different races of
mankind; but with the Tartars, Chinese, etc.,
the voice of the male is said not to differ so
much from that of the female, as in most other
races.