34 Fisher — The Effect of Diet on Endurance. 



been a greater handicap in bis ease tlian in any other of tlie men ; 

 for lie liad been accustomed for six years to heavy gymnasium train- 

 ing, but during tlie year of the experiment this training was given 

 up, largely because of the difficulty in findiijg time for it. If this 

 interpretation is correct, we may liken the experiment to nine men try- 

 ing to swim against a current. The eight who exerted themselves 

 the most succeeded in forging ahead ; the one Avho tried the least 

 drifted backward, though the effect of the swimming (dieting) was to 

 propel him forward. Whether or not E. was actually propelled for- 

 ward by diet must remain a matter of conjecture or inference ; but 

 that the other eight men gained is an established fact. 



Changes in Mental Eitlurance. 



The mental test consisted in adding a specified number of figures. 

 The following tables show the time during which the addition was 

 performed and the number of errors committed : 



TABLE XVI. 



TIME OF PERFORMING A UNIFORM AMOUNT OF ADDITION. 



B E Lq Lw M P R T W Average 



M S M S M S M S M S MS M S M S M S M S 



Time ( Jan. 14 5 40 4 49 6 15 4 54 6 46 3 1 7 6 6 41 4 6 5 29 



of \ Mar. 28 5 16 4 27 4 35 4 15 5 47 2 43 6 32 7 18 4 34 5 3 



adding ( i June 16 4 50 5 9 4 40 4 23 5 50 2 58 7 3 6 5 4 7 5 



This shows that during the fii'st period seven had improved and 

 two had fallen off, and on an average there had been a decrease from 

 5m. 29s. to 5m, 3s., an average improvement of 26s. W. showed an 

 increase in time of adding, although he would naturally have been 

 expected to improve on account of having taken up clerical Avork 

 involving adding. 



During the second period there was an average improvement of 

 only 3s. ; three retrogressed 15s. to 42s., three retrogressed 3s. to 8s., 

 and three improved 26s. to 73s. The fact that the men held their 

 own in the June adding test is probabl}'^ indicative of actual improve- 

 ment, for they were fatigued mentall}^ by examinations, etc., on the 

 day when they entered the June test. During the entire experiment 

 there was an average improvement of 29s. ; seven had improved and 

 two had retrogressed (Is. and 20s.) 



'E., Lw., R. and W. taken on May 31. 



