had a kind of infancy which was a great
deal longer than that of a cow or a sheep, but it was nothing
compared to human infancy in length. This little orang-outang
could not get up and march around, as mammals of less intelligence
do, when he was first born, or within three or four days; but after
three or four weeks or so he would get up, and begin taking hold of
something and pushing it around, just as children push a chair; and
he went through a period of staring at his hands, as human babies
do, and altogether was a good deal slower in getting to the point
where he could take care of himself. And while I was reading of
that I thought, Dear me! if there is any one thing in which the
human race is signally distinguished from other mammals, it is in
the enormous duration of their infancy; but it is a point that I do
not recollect ever seeing any naturalist so much as allude to.

It happened at just that time that I was making researches in
psychology about the organization of experiences, the way in which
conscious intelligent action can pass down into quasi-automatic
action, the generation of instincts, and various allied questions;
and I thought, Can it be that the increase of intelligence in an
animal, if carried beyond a certain point, must necessarily result
in prolongation of the period of infancy,--must necessarily result
in the birth of the mammal at a less developed stage, leaving
something to be done, leaving a good deal to be done, after birth?
And then the argument seemed to come along very naturally, that for
every action of life, every adjustment which a creature makes in
life, whether a muscular adjustment or an intelligent adjustment,
there has got to be some registration effected in the nervous
system, some line of transit worn for nervous force to follow;
there has got to be a connection between certain nerve-centres
before the thing can be done, whether it is the acts of the viscera
or the acts of the limbs, or anything of that sort; and of course
it is obvious that if the creature has not many things to register
in his nervous system, if he has a life which is very simple,
consisting of few actions that are performed with great frequency,
that animal becomes almost automatic in his whole life; and all the
nervous connections that need to be made to enable him to carry on
life get made during the foetal period or during the egg period,
and when he comes to be born, he comes all ready to go to wor