40 Fisher — The Ejfeet of Diet on Endurance. 



Again, the conditions immediately preceding the March and June 

 tests, as compared with those preceding the Januarj' test, were such 

 as to give the advantage to the January test. The latter came soon 

 after the Christmas holidays, when the men, as they themselves 

 stated, felt refreshed and at their best, whereas the March test came 

 just before the Easter recess, after a hard term's work, and the June 

 tests came after a like period of hard work, — in some cases, as of B. 

 and R., immediately after exhausting examinations. 



Finally, the tests themselves were serious drains on vitalit3\ Each 



.required a period of from several days to two weeks for recuperation, 



and each robbed the men temporarily of several pounds of weight. 



The cookless diet experiment for six days also cost something to 



those who took part in it. 



In addition to the tests mentioned in this report was one on Jan- 

 uary 23 of leg-raising, deep knee-bending and arm-stretching, taken 

 after a night from which two hours of sleep were purposely cut off. 

 After consideration, it was decided not to repeat this test as being 

 too fatiguing. It therefore has been omitted from this report ; but 

 it added one more burden for the men. 



When, therefore, we observe the known handicaps, — the over-study, 

 the strain of the tests, the advance of warm weather, the fact that 

 the first test came after rest and the other tests after work, and 

 when we are unable to find any other cause than diet — such as exer- 

 cise, regularitj^ of bed-time or other habits — we are forced to 

 conclude that the only causes which produced the endurance were 

 dietetic. 



Possibly some persons may be disposed to find a convenient escape 

 from this conclusion b}^ ascribing the improvement to suggestion. 

 [Jnder this theory'-, the men impl'oved because they expected to. It 

 is quite true that there may be more force in autosuggestion than 

 most of us realize. But, fortunately, for the present case we scarcely 

 need to argue the point ; for as a matter of fact it was not true that 

 all of the men expected to improve. This was certainly not true 

 before the March test. In fact, the men were about equally divided 

 in their predictions as to the outcome, and used to have animated 

 discussions. Yet, both the confident and the skeptic faction im- 

 }»roved in endurance in the March test ; and so far as I am acquainted 

 with their ])rognostioations and have noted their improvement, there 

 was little if any correlation between those prognostications and their 

 improvement. 



It is of course still possible that some unobserved element has crept 



