PRACTICAL PHASES OF MENTAL FATIGUE. 521 



cially in our large graded schools. But we can at any rate adjust 

 our requirements with some degree of accuracy to the average ca- 

 pacity of the whole. 



Regarding the number of hours of mental application per day 

 which may be safely expected of a pupil in school, investigations 

 have tended to show that there is a danger of requiring too many. 

 AVhen pupils return to school morning after morning without having 

 recovered from the previous day's labors, it is evident that too 

 heavy draughts are being made upon their nervous capital. It may 

 be said in reply that many factors conspire to produce this depleted 

 condition, as insufficient sleep, inadequate nutrition, and outside 

 duties; but the answer is that under such unfavorable circumstances 

 less work may be demanded. As the curriculum is planned in many 

 places, alike in graded and ungraded schools, the pupil is expected 

 to be employed in the school for five or six hours a day no matter 

 what may be his age, and to this work should be added studies at home 

 for the older students. Now, as Kraeplin * has justly observed, 

 Nature ordains that a young child should not give six hours' daily 

 concentrated attention in the schoolroom, but, rather, she has taken 

 pains to implant deeply within him a profound instinct to preserve 

 his mental health by refusing to attend to hard work for such a long 

 period. Consequently, in such an educational regime, the mind of 

 the pupil continually wanders from the duties in hand. The most 

 serious aspect of this is apparent, that when attention is constantly 

 demanded and not given, or when a pupil is pretending or attempt- 

 ing to keep his thoughts turned in a given direction, yet allows them 

 to drift aimlessly because he is practically unable to control them, 

 he is acquiring an unfortunate habit of mental dissipation. It 

 seems certain that healthful and efficient mental activity requires 

 that a child apply himself in a maximum degree for a relatively 

 short period, the duration differing with the age of the individual 

 and the balance of nervous energy to his credit; and then he should 

 relax, attention being released for a time. 



Experiments conducted by Burgerstein f and at Leland Stan- 

 ford Junior University ^ emphasize a particular phase of this princi- 

 ple that too long continued mental application without relaxation 

 induces fatigue more readily than when there are comparatively 

 short periods of effort, followed by intermissions of rest. Thus when 

 pupils (and the younger they are the more is this true) have a given 

 amount of work to do requiring their attention say for an hour and a 

 half they will accomplish most with least waste of energy by break- 

 ing up this long stretch into several parts, interspersing a few min- 



* A Measure of Mental Capacity, Popular Science Monthly, vol. xlix, p. 768. 

 f Op. cit. \ Pedagogical Seminary, vol. iii, pp. 213 et seq. 



