DOCKERAY : PHYSICAL FATIGUE AND MENTAL EFFICIENCY. 233 



easier to discriminate. Possibly this is merely an indication of 

 unusual mental activity. If this was true in regard to his 

 mental condition it certainly was not true in regard to his 

 physical condition in the second test. Do. had walked three 

 hours as rapidly as possible and had covered fifteen miles. 

 Nausea accompanied his feelings of fatigue. 



It is quite certain that the other subjects were considerably 

 fatigued by the harness exercise, particularly W., who worked 

 most conscientiously and whose curve fell gradually through- 

 out the entire twenty minutes. More tests were taken with W. 

 than with any other subject, but his results vary between wide 

 limits. There seems to be no constant tendency in his results 

 in the relation of omissions to errors ; they neither vary to- 

 gether nor oppose each other. It will be noticed that the fourth 

 rest day produced an unusually large increase in the per cent of 

 errors and a considerable increase in the per cent of omissions. 

 The eighth day reversed this and gave extremely large de- 

 creases in both omissions and errors. On the whole, however, 

 the tendency is to decrease the improvement after physical 

 work and the fluctuations are not so great. Do. shows a slightly 

 greater decrease in the per cent of errors after the physical 

 work than after rest, but the per cent of omissions has in- 

 creased to a much greater extent after work than the omis- 

 sions have decreased. Bt. shows a decided decrease in im- 

 provement after work and his daily records are fairly 

 constant. 



Be. manifests the greatest influence of physical fatigue. 

 Her improvement after rest is uniformly great, and after 

 fatigue she almost as uniformly falls below her record in the 

 first test. Bu. is very irregular. It will be noticed that he 

 frequently makes very few mistakes, and at other times 

 makes as many as the other subjects. It is impossible to ac- 

 count for this extreme variability, as Bu. was always a con- 

 scientious, intelligent worker, and the tests were always con- 

 ducted under as nearly the same conditions as possible. He 

 was our youngest subject and of only sophomore rank. It is 

 possible that his variability was due to lack of training. 



A comparison of Do.'s results with the harness and with the 

 walking indicates that the harness has reduced discrimination 

 power as much as walking. If we consider the improvement 

 after twenty minutes' rest, then the harness has had the 



