^"^ I 19(^7 



I. — The Effect of Diet on Endurance, Based on an Experi- 

 ment WITH Nine Healthy Students at Yale University. 



January-June, 1906. 



Introduction. 



There appears to be very little literature on the subject of endur- 

 ance. Since the eiDOch-making work of Mosso, much has been written 

 on fatigue, and many varieties of ergographs have been constructed 

 to record muscular fatigue ; but no systematic study of endurance 

 as such a^jpears to have been made. Even the concept of endurance, 

 as related to strength and fatigue, has been lacking. No corre- 

 lations have been worked out between endurance and the factors 

 upon which it depends, excejDt that it has been a matter of common 

 experience that endurance increases with exercise. In respect to 

 diet, opinions as to its relation to endurance, so far as the writer knows, 

 have rested on no better foundation than the personal impressions of 

 adherents of special dietary systems, such as those of Salisbury, 

 Dewey, Haig, Kellogg, and Fletcher. In Professor Chittenden's 

 painstaking study on " Ph^'siological Economy in Nutrition" he has 

 shown that one result of a gradual and systematic reduction in proteid, 

 from the amount ordinarily consumed, has been an increase in strength, 

 but no data were obtained in respect to endurance. 



The present experiment had a somewhat accidental origin. I was 

 engaged in collecting statistics of labor-power in relation to various 

 factors, among them especially diet. The data were collected because 

 of their economic beariuQ-s and without anv intention at first of mak- 

 ing independent experiments. But some of my students, whom I had 

 engaged to make computations and diagrams, became interested in 

 the material with which they thus came in contact, and expressed a 

 strong desire to tiy dietetic experiments upon themselves. Not 

 being a physiologist, I asked Professor Chittenden if he could not 

 take charge of these experiments for them. It so haj^pened that on 

 account of other similar work he was unable to do so, but suggested 

 that I should conduct them myself. I have done so with consider- 

 able hesitation, not being equipped for physiologic studies. I have 

 therefore restricted my attention to the simpler practical aspects of 

 the problem, although some of the technical points have been inves- 



Trans. Conn. Acad., Vol. XIII. 1 May, 1907. 



