250 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



keen foresight, recognized the significance of this question and carried 

 out one experiment in which an attempt was made to have the subject 

 in a glycogen-poor condition, but the initial respiratory quotient of this 

 subject, 0.799, 1 did not indicate a much lower glycogen storage than 

 that of his two previous experiments with quotients of 0.835 and 0.809, 

 respectively. 



To sum up, the experiments upon the ingestion of carbohydrate show 

 clearly that carbon-dioxide measurements have little significance if 

 unaccompanied by measurements of either the oxygen consumption 

 or the heat production. The increment in the carbon-dioxide produc- 

 tion invariably noted may be caused by three different factors, all of 

 which may be working together, but an actual increase of the heat 

 production can only be shown by oxygen measurements or by direct 

 calorimetric measurements. In considering the three causes for the 

 increment in carbon dioxide, i. e., the replacement of fat by carbo- 

 hydrate in the metabolism, the formation of fat from carbohydrate, or 

 an actual increase in the total katabolism (all of which involve a 

 destruction of carbohydrate) the disappearance of carbohydrate after 

 ingestion due to possible glycogen storage in the body should not be 

 lost sight of. Presumably this latter condition will be best favored by 

 a depletion of the glycogen store in the body previous to the ingestion 

 of the carbohydrate. 



Since the protein katabolism in these experiments plays such a 

 relatively small role, rarely over 15 per cent of the total heat production 

 being derived from protein, we can practically neglect the intermediary 

 transformations of protein in our calculations. Sufficient evidence has, 

 however, been accumulated to show that the contention of Gigon, i. e., 

 that in the niichtern or post-absorptive condition there is constancy in 

 both the nitrogen content of the urine and the character of the katab- 

 olism as indicated by the respiratory quotient, can not hold true. 

 The data in this publication make clear the fact that respiratory quo- 

 tients of the same individual may vary greatly. The careful series of 

 experiments published by Togel, Brezina, and Durig, 2 also show that 

 with the same subject the basal post-absorptive respiratory quotient 

 varied inside of a period of less than 4 months from 0.799 to 0.903. 

 While, therefore, we are fully cognizant of the extremely suggestive 

 and stimulating discussion by Gigon of the constancy of the basal 

 cellular metabolism, established, as he thought, by his determinations 

 of the nitrogen, carbon-dioxide excretion, and basal metabolism, yet 

 we firmly believe that subsequent data can not confirm his assertion 

 (see footnote 2, page 264). In our series of experiments it is wholly 

 impossible to conceive of a constant nitrogen metabolism with a con- 

 stant fat metabolism on which the carbohydrate metabolism is simply 

 superimposed. 



Togel. Brezina, and Durijr, Biorhom. ZoiNohr., 1918, 50, p. 311. -Ibid., p. 206. 



