Metabolism Experiment No. 102. 



27 



sleeping-hours from 1 a. m. to 7 a. ra. Considering the 24 hours from 7 a. m. 

 to 7 a. m., the heat elimination was practically equal to the heat production, 

 as there was but a slight minus correction of a fraction over 2 calories for the 

 change in body weight. 1 



Table 11. 



-Summary of calorimetric measurements and total heat eliminated 

 Metabolism experiment No. 102. 



1 Includes correction for change of body weight from 7 a. m. to 7 a. m. 



2 Total heat production. 



BALANCE OF MATTER AND ENERGY. 



Method of computation. In accordance with the plan used successfully in a 

 previous report, it has been deemed advisable to present results of experiments 

 of this nature, first, as a study of katabolism, and, second, as a study of the 

 extent to which food ingested met the demands upon the body. This method 

 of presentation has specific value in that the errors incidental to the sampling 

 and analysis of foods do not enter into the computations of the total katabolism. 

 Consequently, this experiment will be first treated from the standpoint of the 

 katabolism itself. 



Material katabolized in the body. The computation of the total katabolism 

 is rendered relatively accurate by the numerous determinations made in con- 

 nection with these experiments, for from the analyses of the urine and the 

 gaseous exchange, it is possible for us to determine the total output of nitrogen, 

 carbon, hydrogen, and oxygen. In the calculation of the katabolism, the only 

 income which is considered is the oxygen absorbed from the air. Furthermore, 

 preformed water which is taken with the food and drink does not enter into 

 the calculation. The method of computing the results has been explained in 

 detail in several publications. 2 The data and the materials katabolized are 

 given in table 12. 



1 For a complete discussion of the method of computing the amount of heat residual 

 in the body see Carnegie Institution of Washington Publication No. 77, 1907, p. 46. 



2 Atwater and Benedict, Carnegie Institution of Washington Publication No. 42, 

 1905; Benedict, ibid., Publication No. 77, 1907; Benedict and Milner, U. S. Dept. 

 Agr., Office Exp. Stas. Bui. 175, 1907. 



