14 THE TONER LECTURES. 



pellecl to do severe iutellectual work under pressure for time. His 

 danger, as noted in the six cases that have come under ol)servation 

 in the preparation of the pi-esent paper, is from sedentary hal^its, 

 and from intense and prolonged activity of the mind in certain 

 limited grooves. To some minds scientific work has a fascination 

 which becomes a source of peril ; the worker l^ecomes a willing slave 

 to tasks which are often of his own making. The six cases were all 

 men who labored beyond the requirements of the positions held by 

 them. Assiduous work with the microscope, steady concentration 

 ui)on mathematical and engineering ])roblems, and the laborious 

 collection and comparison of data, produced, after a time, states of 

 mental and nervous hyperrcsthia and exhaustion, which led to 

 albuminuria in one case, to insanity in two, and to temporary nerv- 

 ous collapse in three cases. 



One of these cases, a man highly distinguished in the professional 

 and scientific world, devoted himself with rare enthusiasm to scien- 

 tific work under Governmental auspices. His method was simply 

 one of intense and incessant applicati(jn by day and by night, 

 Sunday and week-day. Warnings in the shape of insomnia, 

 great irritability, mental and physical weariness, oxaluria, and 

 marked loss of weight came and went unheeded. Melancholia de- 

 veloped. Rest and travel twice restored him to mental health, but 

 only to have the same history repeated, and to end with a third 

 and complete mental collapse. Another, a young man who had 

 educated himself scientifically, at the same time earning a living, 

 frequently worked fourteen hours a day at tasks requiring close 

 mental concentration. The tendency to over-work is greater among 

 men who have, without the training of schools, raised themselves to 

 honorable rank in science and literature than among those who 

 have had the advantage of a systematic education. 



The teachers that have fallen under my notice have been, with 

 one exception (a college professor), principals of male grammar 

 .schools in Philadeli^hia. Five of them broke down completely 

 from menial over-work, and the worrv which went with and grew 



