cases these are slight and inconspicuous. In dogs, horses, and apes
there is marked teachableness, and there are also marked differences in
individual character.

But in the non-human animal world all these phenomena are but slightly
developed. They are but the dim adumbrations of what was by and by to
bloom forth in the human race. They can scarcely be said to have served
as a prophecy of the revolution that was to come. One generation of dumb
beasts is after all very like another, and from studying the careers of
the mastodon, the hipparion, the sabre-toothed lion, or even the
dryopithecus, an observer in the Miocene age could never have foreseen
the possibility of a creature endowed with such a boundless capacity of
progress as the modern Man. Nevertheless, however dimly suggestive was
this group of phenomena, it contained the germ of all that is preëminent
in humanity. In the direct line of our ancestry it only needed that the
period of infancy should be sufficiently prolonged, in order that a
creature should at length appear, endowed with the teachableness, the
individuality, and the capacity for progress which are the peculiar
prerogatives of fully-developed Man.[7] In this direct line the manlike
apes of Africa and the Indian Archipelago have advanced far beyond the
mammalian world in general. Along with a cerebral surface, and an
accompanying intelligence, far greater than that of other mammals, these
tailless apes begin life as helpless babies, and are unable to walk, to
feed themselves, or to grasp objects with precision until they are two
or three months old. These apes have thus advanced a little way upon the
peculiar road which our half-human forefathers began to travel as soon
as psychical variations came to be of more use to the species than
variations in bodily structure. The gulf by which the lowest known man
is separated from the highest known ape consists in the great increase
of his cerebral surface, with the accompanying intelligence, and in the