RESEARCHES BY OTHER INVESTIGATORS. 5 



higher than that usually found, and may in part be explained by the 

 fact that, as Waller himself states, his method determines only the 

 carbon-dioxide production, a respiratory quotient is assumed, and 

 there is an acknowledged error of 5 per cent. In general, his values 

 run somewhat higher than those commonly accepted as a result of 

 other walking experiments. 



Benedict, Miles, Roth, and Smith, 1 in the report of a study on the 

 effects of restricted diet, include the measurement of the gaseous 

 exchange during level walking on a treadmill of a group of 12 young 

 men in normal condition and of the same group after 20 days of re- 

 stricted diet. They likewise report the gaseous exchange during walking 

 of a group of 1 1 men after they had been on a restricted diet for a period 

 of 120 days. A special closed-chamber method was used, and the 

 carbon dioxide produced and the oxygen consumed were determined 

 by analysis of the chamber air. They found the average cost per 

 horizontal kilogrammeter for the normal men to be 0.597 gram-calorie, 

 and for the same group after 20 days of restricted diet 0.562 gram- 

 calorie. For the group with a restricted diet for 120 days the cost 

 per horizontal kilogrammeter was 0.522 gram-calorie, thus indicating 

 a somewhat greater efficiency per unit of work for the men who were 

 on a restricted diet and much below their usual body-weight. These 

 figures, the authors state, were for brief periods of moderate speed 

 (70 meters per minute) and do not apply to conditions in which con- 

 tinued exercise and stamina might be prime requisites. 



Cathcart and Orr, 2 using the Douglas bag method, made a series 

 of studies on the energy requirements for the various forms of exercise 

 required of British recruits. Inasmuch as the experiments were 

 carried out under various conditions of weather and terrain, the 

 authors distinctly state that all they could expect to obtain was an 

 average of the energy expended in performing any given type of drill. 

 Among the many forms of exercise reported in their publication was 

 included that of marching with light (15.3 kg.), medium (20.5 kg.), 

 and heavy (25 kg.) loads. The speed was 91.4 meters per minute 

 on a comparatively level and smooth stretch of road. For these con- 

 ditions they found the cost per horizontal kilogrammeter to be 0.543, 

 0.638, and 0.672 gram-calorie for the several loads. In addition to 

 these field tests, a series was also made on one of the authors wherein 

 the details are more nearly those of the laboratory research in which 

 the effects of diet and the effects of velocity and load were studied. 

 Under these conditions they found an increased cost per horizontal 

 kilogrammeter with increase in speed and load from approximately 

 0.52 gram-calorie for a speed of 57 meters per minute to 0.85 gram- 

 Benedict, Miles, Roth, and Smith, Carnegie Inat. Wash. Pub. No. 280, 1919. p. 546. 

 2 Cathcart and Orr, The energy expenditure of the infantry recruit in training. H. M. Stationery 

 Office, London, 1919. 



