There is no doubt that the very earliest men spent their lives much as monkeys now do. They probably lived partly in trees before they learned how to build houses in Fig. 7. which they could take shelter from bad weather and when threatened by animals that were much stronger and could run far more swiftly than they. Thus our hands were once developed for climbing about trees, and since that time have changed very in shape. As man became civilized, his hands were put to nobler uses; they were his best instruments for accomplishing all he achieved. Our hands are thus much more flexible Fig. 7. and capable of a far greater variety of movements than the hands of the less civilized monkey.
The hind foot of the monkey was not well suited for man's way of life. One great difference between man and the monkeys is that man walks and runs in an upright position on his hind feet alone, while even the most manlike of the apes walk only partly upright, not supported entirely by their feet but helped along by their hands, which, on account of the great length of the arms, can easily reach the ground. In a man, walking upright, the weight of the body is thrown entirely on the hind limbs, which in him become the lower limbs, and the feet are needed to form a firm pedestal for the whole upright body. Thus in man, the once climbing feet having given up climbing, the useless thumb gradually changed back again into a simple great toe, and the first joints of the rays lengthened out to form a firm flat sole. We can still see some signs of the former thumblike condition of the great toe in little children and in some foreign races. In babies, the great toe is often more or less opposable to the others, and among the Japanese it is still so much so that a Japanese workwoman often holds the work she wants to stretch between her toes, which are able to grasp it firmly.
Men and women have, as a rule, five toes and five fingers, the largest number found in animals; but it is by no means certain that this number will always be retained. The foot of a civilized man is always covered by stockings and shoes, and the toes are hardly used at all, and, like the toes not used in the feet of animals, appear to be diminishing in size. The little toe in a comparatively large number of human beings already has only two joints, and some of the other toes also seem to be becoming shorter. It is thus quite possible that at some future time the human little toe will altogether disappear, and that man may have only four toes, or even, in course of time, fewer than four.