His habit of walking is peculiar. The greater part of the weight is borne upon the legs. The sole of the foot is placed almost flat on the ground, but the pressure is greatest along the outer edge, in the line of the last digit. This is easily noticed where he walks over plastic ground. In the act of walking he always uses the hands, but he does not place the palms on the ground. He uses the backs of the fingers instead. Sometimes only the first joints or phalanges, resting upon the nails, are placed on the ground. At other times the first and second joints are used. I have seen one specimen that, when walking, employed the backs of all his fingers, from the knuckles to the nails. The integument on these parts is not callous, like that of the palm. The color pigment is distributed the same as on other exposed parts of the body. These facts show that the weight of the body is not borne on the fore limbs, as it is in the case of a true quadruped, but indicate that the hand is only used to balance the body while in the act of walking and to shift the weight from foot to foot. The weight is, therefore, not equally distributed between the hands and the feet, and the animal cannot truly be said to be a quadruped in habit. His waddling gait is caused by his short legs, stooping habit, and heavy body. All animals having stout bodies and short legs are predisposed to a waddling motion, which is due to the wide angle between the weight and the changing center of gravity. This motion is more conspicuous in bipeds than in quadrupeds, because the base supporting the weight is reduced to a single point. The chimpanzee is neither a true quadruped nor a true biped, but combines the habits of both. It appears to be a transition state from the former to the latter. Vestiges of this mixed habit are still to be found in man. In the act of walking his arms alternate in motion with his legs. This suggests the idea that he may have had, at some time, a similar habit of locomotion. Such a fact does not necessarily show that he was ever an ape, but it does point to the belief that he has once occupied a horizon in nature like that now occupied by the ape, and that having emerged from it, he still retains traces of the habit. This peculiarity is still more easily observed in children than in adults. In early infancy all children are inclined to be bow-legged. In their first efforts at walking they invariably press most of their weight on the outer edge of the foot and curve the toes inward, as if to grasp the surface on which the foot is placed. The instinct of prehension cannot be mistaken. It differs in degree in different races, and is vastly more pronounced in negro infants than in white ones.