Page:Popular Science Monthly Volume 50.djvu/541

Rh and colleges work in ignorance of the needs of the brain for its steadily strengthening development?

I was much interested to see in the October issue of the Popular Science Monthly a paper by Prof. Kraepelin, of Heidelberg, bearing on this point. His paper reports the result of experiments in "measuring the mental capacity of individuals." The measure is afforded by determining the number of small similar problems resolved by the subject in a given time—such, for example, as the continuous addition of a column of numbers. "Other means of measuring the capacity of a subject are afforded by the ease with which he is diverted from his task, or his susceptibility to disturbing influences from without and within; his elasticity, or the readiness with which he recovers from the effects of fatigue or diversion; and the way he is affected by taking food, physical exercise, and the time he has for sleep."

The experiment in addition, as made upon young men, showed that their facility in addition fell off at the beginning of the second hour. Experiments made by Prof. Burgerstein, of Vienna, showed that a quarter of an hour of simple work is enough to develop the first signs of fatigue in a twelve-year-old pupil.

Prof. Kraepelin claims that when fatigue "has once gained the upper hand, a speedy and unintermitted decline of efficiency ensues. The time when this shall take place depends on the degree of capacity already reached, the personal peculiarity, and casual influences."

It appears from these experiments that the mental vigor of most men is usually maintained at a certain height for the longest time in the forenoon. The rapidity with which one of the persons experimented upon could perform his tasks in addition sank about a third after a night journey by railway with insufficient sleep. Another experimenter could detect the effects of keeping himself awake all night in a gradual decrease in vigor lasting through four days.

The paper concludes as follows:

"When, now, we look back at the conditions we have discovered that control mental vigor, we conclude that our children are exposed by the extent and arrangement of study work in the schools to great perils for their mental and physical development. The questions that press upon us in this matter are of such importance that we all have reason to give them our full, undivided attention. We are only at the beginning of a real hygiene of mental labor, but the results we have obtained in this research, fully indicating the nature and operation of the dangers, point with equal clearness to the character of the preventive and remedial measures which should be sought and applied."

The president of one of our great universities has been quoted