Page:Popular Science Monthly Volume 53.djvu/204

190 after a careful examination by a competent physician, that his condition would warrant a prolonged and severe muscular effort, the result on the moral and bodily habits of a certain class of young men would be superior to any persuasive or semireligious method that the world has yet premonstrated.

What has been said concerning poisoning by the non-elimination of effete products refers also to the nerves and the brain. As the muscles work faster, so do the central nerve cells which send the stimulating impulses to these muscles. These latter cells become fatigued sooner than the muscles. This is a grand feature of physiologic economy, for, did not this condition exist, the muscle would be worked to an irreparable point. The muscular differences noted in individuals are in reality the difference in the nerve cells, the action of the muscle indicating the activity of the central nervous system. When the muscles are being exercised the nerve cells are being exercised, and the effect of exercise on the nerve cells indirectly determines the muscular activity.

It is the general impression among athletes that exhaustion and loss of wind is due to the inability to consume sufficient oxygen and exhale rapidly enough carbon dioxide. When the muscle is moving rapidly and forcibly it is true that it demands more oxygen, and gives off to the blood more carbon dioxide than when at rest. When a man is running as fast as he can make his limbs move he is able to keep up the pace but for a short distance unless, like the hunted hare, he runs to his death. On account of the forced, vigorous, and rapid muscular action in this case, the poisonous materials are thrown into the blood, to be carried to all parts of the body—muscles, nerves, brain. The heart is affected by this poison through the nerve cells controlling that organ; the muscles of respiration are similarly disturbed. The panting, distressed efforts of breathing, sidelong tumbling, anhelation, and final semiconsciousness of the hunted stag or hare are a good example of acute auto-intoxication ending in death. This latter deplorable condition is not unknown among the annals of human strife for athletic honors, even with our present advanced knowledge of physiology.

One of the main "clearing houses" of the body, by which the blood is cleared constantly of all its poison, is the liver. The minute cells of this organ each have their own individual work to perform in transforming the toxic material into harmless substances. The cells of this "clearing house" are delicate little organs, and will not stand abuse. All habits having a tendency to cause dyspepsia—eating