Eelations between Factors of Metabolism. 2-2? 



holm laboratory. Sonden and Tigerstedt are inclined to consider Katzenstein's 

 results as more accurate. Using an ergometer with 5 different subjects, the 

 authors found for each kilogrammeter of work an increment in carbon dioxide 

 of 0.003319 gram, which agrees quite closely with the value found by Katzen- 

 stein when using an ergometer, namely, 0.00317 gram. Making allowances for 

 the work required to turn the ergostat without a load, the authors found that 

 for each kilogrammeter of efficient work, the corresponding increase in the 

 carbon dioxide was equal to 0.00368 gram. 



Heinemann, 1 taking into account the variations in the carbon-dioxide elimi- 

 nation due to diet, made a series of experiments with the ergometer in which 

 a fat diet, a carbohydrate diet, and a protein diet were given. The carbon- 

 dioxide production per kilogrammeter of work on the ergometer was 1.445 c. c. 

 with fat, 1.956 c. c. with carbohydrate, and 1.896 c. c. with protein. The 

 average value found by Katzenstein and by Sonden and Tigerstedt with a 

 mixed diet was 1.522 e. c. of carbon dioxide per kilogrammeter of work. In- 

 asmuch as with an ordinary mixed diet there would be more carbohydrate 

 than fat, the values found by Heinemann must be considered as somewhat 

 larger than those found by Katzenstein or by Sonden and Tigerstedt. 



The noticeable difference between the work experiments made by Sonden and 

 Tigerstedt, by Katzenstein, and by Heinemann, and those made bv us at Wes- 

 levan University 2 is that in the former, the arms were used to rotate a brake- 

 ergometer, while in the latter, the muscular activity was with the legs, which 

 were used to rotate the wheel of a bicycle-ergometer. A comparison of the 

 results found is, therefore, of unusual interest. In table 94 are recorded the 

 increase in the carbon-dioxide elimination as a result of muscular work, the 

 heat equivalent of the external muscular work expressed in terms of calories and 

 again as kilogrammeters of work, and finally the increase of carbon dioxide per 

 kilogrammeter and the kilogrammeters per gram of increase of carbon dioxide. 



In a series of experiments with a professional bicycle-rider, N". B., the ex- 

 ternal muscular work in calories per hour varied from 59.9 to 115.7; the latter 

 figure represented practically the limit of endurance and strength of the sub- 

 ject. The increase of carbon dioxide per kilogrammeter of work varied from 

 0.00363 to 0.00425 gram, averaging for the 6 experiments 0.00391 gram, these 

 results being somewhat larger than those found by Sonden and Tigerstedt or by 

 Katzenstein. For every gram increase of carbon dioxide, therefore, there was 

 on the average 257 kilogrammeters of work done. There is certainly a remark- 

 able agreement in results obtained by two such widely varying methods, one by 

 using a brake ergometer moved by the arms, the carbon-dioxide elimination 

 being determined in a large respiration chamber, and the other by using a 

 special bicycle ergometer which had been carefully calibrated and the heat 

 equivalent of muscular work very accurately measured, and yet the compared 

 values are certainly within the limits of physiological error. 



1 Heinemann, Archiv f. d. ges. Physiologie, 1901, 83; p. 441. 



2 Benedict and Carpenter, U. S. Dept. Agr., Office Expt. Stas. Bui. 208, 1909. 



