o'SHEA — ASPECTS OF MENTAL ECONOMY. 189 



even regarding these varying and modifying factors, that uni- 

 versity students on the whole cannot undertake with safety more 

 than eight hours a day of difficult intellectual labor. 1 It is im- 

 portant to note, however, that during these eight hours the at- 

 tention is to be concentrated upon mental tasks ; mind wander- 

 ing and reverie are not to be considered as work. If we com- 

 pare the stint of our students with this as a sort of standard 

 we find that some work too much, while others do not tax their 

 energies to a legitimate extent. One student reports one hour 

 spent in study ; four, two hours ; twelve, three hours ; thirty-four, 

 four hours ; fifty, five hours ; seventy-two, six hours ; thirty-nine, 

 eight hours ; eleven, nine hours ; thirteen, ten hours ; four, eleven 

 hours ; one, fourteen hours. It is probable that the students re- 

 porting one or two hours devoted to study did not take into ac- 

 count time spent in the laboratories, so that their estimate is of 

 no value to us here. About all that can be said is that students 

 working ten, eleven, and fourteen hours a day are likely to draw 

 too heavily upon their resources. 



And yet it should be remarked in passing that the injurious 

 effects of study upon the health of students is in all likelihood 

 due more largely to the unhygienic conditions under which the 

 work is carried on than to mental application itself. It seems 

 to be true that during waking life the mind is constantly active 

 in some direction ; and if study could be done under proper con- 

 ditions, it is probable that it would be no more fatiguing than 

 other sorts of mental occupation. It seems to me it is really 

 not so much a question of the amount of study as of the circum- 

 stances under which the study is carried on; 2 except, of course, 

 that if one spends fourteen hours a day over his books he cannot 

 meet the requirements in respect of exercise and sleep discussed 

 above. 



1 See a summary of six articles on mental fatigue, Psychological Review, Vol. 

 IV, p. 548, et. seq. President Elliot recommends his students to spend but eight 

 hours in study. Kellogg, in Good Health for March, 1900, says the old rule 

 of eight hours for work, eight hours for exercise and meals, and eight hours for 

 sleep, is one that ought to be obeyed by every persoD. 



s See O'Shea: The Hygiene of School-work; Kindergarten Review, May, 1899. 



