Passive Habits.

The habits of man concerned in the modus operandi of this change are passive, and two in number; that of sitting with his back against some supporting object, and of lying in sleep with his head more or less raised on a pillow or its equivalent. In contrast with man, lemurs and apes inhabit trees during their many hours of rest, and I doubt if the number of hours thus spent by these and other wild animals to that spent in active exercise is less than three to one, so that their attitudes of rest would, if calculated to do so, contribute much towards any change occurring in the patterns of hair. But, seeing that the ape-fashion is similar to that of the lemur, and that this normal arrangement is calculated only to be confirmed by the action of gravity and the dripping of rain, and that they do not greatly indulge themselves, if at all, in their equivalent for man’s armchairs, nothing else would be expected in the hairy covering of their backs than what we find.

The increasing tendency to the upright position in Eoanthropus Dawsoni and Pithecanthropus Erectus to say nothing of the men of Cromagnon—led man to use as supports for his back the walls of his rough caves which he had adopted as dwellings instead of the branches of trees and the nests of the ape. He no longer affected entirely those hardy habits of sitting without support for his back that were de rigueur in his ancestors, who probably looked upon him with as much disapproval as certain erect old ladies of the old school display towards the use of easy chairs by the rising genera­tion. Wearied with the struggle for food, and against his savage rivals, he rested his back against the sides of his rude abode. When he slept in this attitude the relaxa­tion of his voluntary muscles allowed mechanical forces to come into action which tended to oppose the downward trend of the hair. We know from our own experience that when sitting asleep with our backs supported there always occurs a certain amount of sinking down of the trunk. In this attitude are present, then, such conditions of the back and its hairy covering as give rise to mechanical forces which would interfere with the direction of the hair. These are, a heavy body, tending to slip downwards slightly while resting against a fixed surface, a growing tissue easily diverted from its normal course, and many hours spent in the attitude in question.

The effects of these conditions increased with the increasing tendency of developing man to attend to his bodily comfort.

But man spends also on the average at least a third of his whole existence lying in sleep with his head on a pillow of some kind, perhaps the skull of a Felis Groeneveldtii in the case of Pithecanthropus Erectus, and other such better objects, as he made more study of the art of being comfortable. Those who know much of children and sick persons and have watched them in sleep know that the habit of lying on one or other side prevails largely over that of lying on the back. The head being more or less raised by a pillow, the human sleeper, even when lying on his back and more so when lying on his side, is in a potentially and actually sliding position, a fact well known to most persons from their own experience. It is easy to see how such conditions are tending for a third of a man’s whole life to reverse in some degree the direction of his hair and how they act as we saw in the case of the sitting posture. But the very common lateral position in sleep contributes its own peculiar share in pushing the hair towards the spine, ceasing to do so only when the prominent muscular border of the vertebral furrow is reached. I think it will escape no careful observer of these simple facts of man’s resting life, who also notes the remarkable course of the arrows on his back, that the facts and their present explana­tion fit one another like a Chubb lock and its key. The only alternative sugges­tion of the facts is that some being with diabolic power has been at work and laying a trap for poor human biologists in the 20th century A.D.

In confirma­tion of this process I would refer to an example which agrees very closely with the above explana­tion. I knew an invalid suffering from pleurisy and lung-disease who was much confined to bed, spending much of his time propped high up on pillows. He had long dark hair on his back and I was often struck, when examining him, with the remarkable way in which the hairs were dragged upon so that they pointed nearly in a vertical upward direction. Here was a little instance of an undesigned experiment in the dynamics of hair.