Page:Popular Science Monthly Volume 65.djvu/412

408 a long time with very little bodily activity, but the omission is a grave peril.

This capacity for passive circulatory equipoise varies widely, but can not be relied upon to carry any one far unless supplemented by a moderate amount of voluntary action. Some folk claim to obtain enough physical stimulus from mental activity, especially when energetically directed, to suffice for their apparent needs. By intense cerebral energizing undoubtedly metabolism is stimulated, more food demanded and waste disposed of, than when thought is lowered to musings. Some can do with active conversations and laughing. Also music acts wholesomely in the same way. Hence it is compatible with fair health to live a sedentary life, but only if the circumstances of life be, and remain, uniform and wholesome, and the bodily functions so symmetrically carried on that no great strains come and no nutritive nor degenerative disorders arise.

For all, young and old, it is important, in order that full mental and physical health be maintained, that systematized bodily activities shall be practised with some regularity. From this conclusion there is no escape save by self-deception. Assuming then that we have a perfectly normal body upon which to reckon influences for good or evil, we will proceed to analyze the effect of voluntary movement. If a person is entirely oblivious to his own consciousness, that is, entirely free from hyperconsciousness, movements will be made easily and in accordance with instinctive impulses. If the mechanism be perfect or nearly so, the movements made in the ordinary activities of daily life will be entirely natural and consistent with the special structure and abilities of the individual. Provided also that the opportunities for these movements be natural, and sufficiently varied, and if there be adequate stimulus to move, and continue to move, throughout the ordinary exigencies of a working day, and further, if nothing interferes with the normality of these movements, the result should be perfect action and development.

It rarely happens, however, that such a status is maintained. Several influences creep in more or less forcefully to interfere with the symmetry and naturalness of bodily movements. The first factors which should be reckoned with in altering the symmetry of the body are minor inherent defects of development in the skeletal structures by which a tendency is early established for the stronger side to overwork the weaker one. This will be better understood in the brief anatomical description which will be given later. The second thing is dress. In proportion as dress exercises undue pressure on one or another part, it is capable of modifying structure and altering growth. What these influences are we shall mention in detail later. Next such influences as environment, habits, fashion and energy or indolence