PREVIOUS STUDIES OF THE METABOLISM OF CHILDREN. 



the influence of puberty, the figures are, in the light of modern studies at 

 this age, worthy of even greater consideration. Andral and Gavarret 

 employed a copper mask attached to the subject's face and collected 

 the expired air in large glass globes, this air being subsequently ana- 

 lyzed. They report a large series of experiments (8 to 13 minutes 

 long) with a great many individuals, some of them children. The 

 experiments were all made in the early afternoon and at the same 

 interval after food, and an attempt was made on the part of the experi- 

 menters to have all subjects with the same degree of muscular activity, 

 presumably in the sitting position. Although reported on the basis 

 of carbon per hour, their data have been recalculated to the basis of 

 carbon dioxide by Sonden and Tigerstedt 1 and are presented in table 1 

 as given by them, together with our computations of the heat produc- 

 tion per 24 hours. 



TABLE 1. Metabolism of boys and girls (Andral and Gavarret). 



1 Computed by Sonden and Tigerstedt, Skand. Arch. f. Physiol., 1895, 6, pp. 54 and 56. 



2 Sonden and Tigerstedt give 16.7 gms. COz; this value corrected by us. 



3 Heat computed from carbon-dioxide production, assuming 3 calories per gram of carbon dioxide. 



The authors conclude that with males there is a steady increase in 

 the carbon-dioxide production between 8 and 30 years. At the time 

 of puberty this increase suddenly becomes very large. Thus, the 

 amount of carbon burned in one hour's time increases progressively 

 from 5 grams in the case of a boy 8 years old to 8.7 grams in the case 

 of a boy 15 years old, while with a young man of 16 years the amount 

 was 10.2 grams. With well-developed males from 20 to 28 years of 

 age the values for carbon increase gradually to 11.2 grams and 12.4 

 grams. 



With the females there is likewise an increase in carbon-dioxide 

 production with increasing age, but at the time of puberty this increase 



1 Sonden and Tigerstedt, Skand. Arch. f. Physiol., 1895, 6, pp. 54 and 56. 



