Jdlt 16, 1915] 



SCIENCE 



79 



heat, the average values obtained were consequently he must have burned up in 

 those given in Table III. these three hours as much material as would 



TABLE III 



Experiments on Bicycle Eiders {Calories per Sour) 



Efficiency, 



Resting Working Work Done Per Cent. 



J. C. W. (college athlete) 112 339 49 21.6 



B. F. D. (college athlete) 106 318 45 21.2 



A. L. L. (untrained) — 326 46 20.8 



E. P. S. (untrained) ? 399 51 18.1 



jST. B. (professional rider) 92 619 112 21.3 



471 79 20.8 



401 65 21.0 



382 60 20.7 



The figures in Table III. shed a most inter- ordinarily be burned by a subject at rest 

 esting light on the question of training. It in twenty-four hours. On this same basis, 

 has commonly been supposed that when a he would need three meals every three 

 person is trained, the muscles become more hours or one square meal an hour, 

 effective and consequently there is a greater A new series of muscular work experi- 

 production of work for the same expendi- ments is in progress in the Nutrition Labo- 

 ture. Here we find that in the first place ratory under the direction of Professor 

 the two men, A. L. L. and E. F. S., who H. M. Smith in which the subject walks on 

 were wholly untrained, and indeed wholly a specially-designed treadmill at varying 

 unfamiliar with the bicycle, accomplished rates of speed, breathing through a mouth- 

 as much work as did the college athletes, piece into a respiration apparatus which 

 J. C. W. and B. F. D., with an efficiency measures the carbon-dioxide excretion and 

 very little less than that of the first two. the oxygen consumption. As a result of 

 When we examine the results obtained this investigation it has been found that 

 with the professional bicycle rider, Mr. in walking on a level road at a moderate 

 Nat Butler, we find that he was able gait (70 to 80 meters per minute) there is 

 by virtue of his strength to accomplish a an increase in the heat production for each 

 very great deal more work than any of the kilogram of body weight moved forward 

 other men, but as a matter of fact his one meter, which is equivalent to about 0.5 

 efficiency was not materially greater than small calorie. With an increase in velocity 

 that of the college athletes, or, indeed, the the energy expenditure is rapidly aug- 

 untrained men. mented and during running may become 



In order to produce this heat in the body 60 per cent, more per unit of weight trans- 

 there must have been vigorous combustion, ported than that of the subject walking at 

 either of body substance, in case the subject a moderate rate. Studies are also being 

 did not have food enough, or of food mate- made with this treadmill in which the sub- 

 rial previously eaten. We have found as a jeet walks on an incline, the work of ascent 

 result of a large number of experiments thus being added to the work of walking on 

 that a man at rest, doing no visible external a level. 



muscular work, requires not far from 2,000 In this investigation, which is elaborate, 

 calories for maintenance during twenty- a large number of simultaneous measure- 

 four hours. It will be seen that in three ments have been attempted. In addition 

 hours Mr. Butler produced nearly this to measurements of the carbon-dioxide ex- 

 amount when at severe muscular work; eretion and the oxygen consumption, we 



