The Descent of Man

this head in the two works so often quoted, by
Brehm and Rengger.); and since fowls give distinct
warnings for danger on the ground, or in
the sky from hawks (both, as well as a third cry,
intelligible to dogs) (58. Houzeau gives a very
curious account of his observations on this subject
in his 'Facultes Mentales des Animaux,'
tom. ii. p. 348.), may not some unusually wise
ape- like animal have imitated the growl of a
beast of prey, and thus told his fellow-monkeys
the nature of the expected danger? This would
have been a first step in the formation of a language.
As the voice was used more and more, the vocal
organs would have been strengthened and
perfected through the principle of the inherited
effects of use; and this would have reacted on
the power of speech. But the relation between
the continued use of language and the development
of the brain, has no doubt been far
more important. The mental powers in some