Page:Popular Science Monthly Volume 71.djvu/253

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than his parents. This means not only that he should secure more tangible results, but that he should develop and expend more force than his ancestors. Each one stands on the shoulders of the past and may utilize all the accumulations of the past. In order to accomplish more than our forefathers, it is absolutely necessary, however, to husband our forces. But with the increase of potentialities, we must also reckon with the fact of the manifold additional ways inviting and exciting to depletion of powers. As an illustration, let us note the excessive stimulation to which the eye is subjected. In our present civilization we have come to depend more and more upon vision. The strain upon the eye in gaining knowledge of the objective realities about us has been increased a thousandfold by modern modes of travel. In addition, we must use the eye to interpret language symbols about myriads of things inaccessible to personal inspection. Primitive man had only a narrow range of things to see, and those usually at some distance. Hence he knew not of eye strain resulting from the microscopic scrutiny of a vast kaleidoscopic scene. Formerly man could deliberate in seeing the few things within his range. But now he becomes a globe-trotter, compacting into a few weeks the view of scores of nations, vast expanses of country, the collections of ages, and the unceasing activities of the heterogeneous throng.

In a week^s jaunt and doing a world's fair, present-day man sees more and hears more, than was possible in a whole lifetime, a century ago. Besides these activities the eye is made to do duty in reading the twenty-four-page daily, the forty-eight-page Sunday edition, in scanning a half-dozen weeklies, going through a cartload of magazines, to say nothing of all the latest books which one is supposed to read.

The ear is equally assailed with the ceaseless hum of voices, door bells, telephone calls, whir of the trolley, the shriek and clang of the locomotive, the maddening grind of the sleeping car or the twin-screw steamer (upon which we take our vacation rest!), the deafening roar of the factory, the clatter of galloping hoofs and rattle of wheels over paved streets. Even at night we must be assailed, business must not stand still, goods must be sent by return mail, limited trains must outdo lightning specials. Even on Sundays we are not permitted to listen to restful sermons—they must be such as to give rise to glaring head-lines, and the music is often of ear-splitting pitch.

The first and foremost great law of mental dietetics that should be impressed early and often is that one long ago stated by Juvenal, viz, mens sana in corpore sano. Every parent and every teacher should understand that the first business of the child is to become a good animal; childhood years should be largely vegetative. His primal inheritance is physical. To have big lungs, firm muscles, elastic step, ruddy cheeks and scintillating, unspectacled eyes, and every sense alert, at the close of youth are priceless possessions with which a knowledge