We come now to the system which depends upon, yet rules, all others. Affections of the nervous system are now and have been for some time on the increase. If I were asked to name that part of the human organism upon which the health and strength of an individual most depends, I should unhesitatingly say the nervous system. The reflex actions are those produced by some cause exciting a nerve which has its termination in the spinal cord and which does not extend into the brain. Walking, called automatic, is one of the reflex actions. Did all nerves terminate in the spinal cord and none of them enter the brain, there could be no such thing as sensation, and parts of the body might be badly injured without the person knowing it. The law of eccentric projection is that by which we refer sensation to the end of the nerve on which it is received, instead of at the point of contact with exciting cause. Neuralgia is caused by anything that worries or troubles a person's mind. Malaria is also a fruitful cause of neuralgia.

This disease is hereditary. Among 83 cases of neuralgia Abernethy found that nearly all had their start in inherited nervous disease. A draught of cold air is enough to cause neuralgia in a predisposed person. Among the articles that produce degeneration of the nerve tissues, alcohol stands prominent. The hard drinker, though young in years, in regard to his tissues is old.