In order to give foundation and strength to our belief in the benefits of physical exercise, let us consider what it does, and how really necessary it is. Though we admit the truth of all the wise sayings with regard to a "sane mind in a sound body," we are yet too apt to regard the sound body as a mere accident of inheritance or environment. So we read the proposition as an hypothetical one, viz., "If the body is sound, the mind will be sane." Few but physicians read it as indicating a connection between body and mind, by means of which we can make, or help to make, a good healthy brain by making a good sound body. In the fact that the brain always seems to direct the body, we are prone to forget that the body carries the brain and feeds it with its own life. If the body has good blood, the brain will have good blood also. If the body does not furnish good material, the brain will do, according to its capacity, poor work, or will not work at all. That many men of weak bodies have done good brain-work in their day is true, but many such men have been hindered from doing better work by physical weakness. Moreover, can any man say that the work done would not have been greater or better if the men doing it had had better bodies? After the body has attained maturity, most men recognize the connection and sympathy between mind and body. During the time of growth, however, this interdependence is often taken into small account.
There are two kinds of brain-work—one which we may very properly call body brain-work, and the other mind brain-work. Most people, including a great many educators of youth, consider mind brain-work to be the only kind of brain-work. But body brain-work is quite as essential to the healthy existence of the brain, and really comes first in the order of brain-growth. The child, too young to know anything except its bodily wants, and conscious of them only when the denial of them causes pain, develops brain every time it makes a will-directed effort to grasp the thing it wants. The movement of its hand is as necessary to the development of its brain as the guidance and government of the brain are to the growth of the hand. What is true of the hand is true of the other bodily organs whose motion is under the control of the will. They and the brain are developed by reciprocal action. Interfere with this body brain-work in childhood, or at any period of growth, either by repressing it or by diverting from it too much vital energy to mind brain-work, such as is involved in the acquisition of knowledge, and you not only stunt the body, but also enfeeble the brain, by depriving both of their proper growth. The worst feature of such interference, at such a time, is that the evil then done can not be remedied, and the power lost to body and brain can never be regained.
Care to guard against this interference is all the more necessary in cases in which the brain is large or sensitive. Now, will any man say
- Dr. Clarke, "Building of a Brain."