138 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



striking feature of this chart is that above the age of 1 year practically 

 all of the earlier observations lie above the line, the exceptions being 

 two boys studied by Du Bois and one boy observed by Magnus-Levy 

 and Falk. Aside from these three cases, the general trend of metab- 

 olism in practically all the other studies was at a noticeably higher 

 level than that found by us. A number of Magnus-Levy's observa- 

 tions lie very close to our line; this would seem to confute the general 

 conception suggested by Harris and Benedict 1 that the observations 

 of Magnus-Levy possibly indicate a racial difference in metabolism. 

 From a critical analysis of the earlier researches it would seem probable 

 that the conditions for basal metabolism, particularly with respect 

 to muscular activity, were by no means so rigidly adhered to in the 

 earlier observations as in ours, and we believe that no evidence exists 

 thus far to suggest that the differences in the results may not be 

 entirely explained by a difference in activity, without the necessity 

 of implying a racial difference in the metabolic level. Certainly, with 

 Du Bois's data, we are dealing with American material. 



Cals. 



TOTAL CALORIES REFERRED TO AGE- 



GIRLS. 



Yrs. V 23456 7 



FIG. 25. Basal heat production of girls per 24 hours referred to age (earlier investigators). 



Comparison for girls. While very few measurements of the metab- 

 olism of girls have been made, for the sake of consistency we have 

 plotted in figure 25 the few observations we have been able to find 

 in the literature and have laid our curve for girls upon the same chart. 

 We find here two values of Magnus-Levy below our line; the other 

 values lie above it. The two low values of Magnus-Levy for 12-year- 

 old girls are of special interest, since, in the analysis of Magnus-Levy's 

 data made by Harris and Benedict, 2 these two girls had a predicted 



1 Harris and Benedict, Carnegie Inst. Wash. Pub. No. 279, 1919, p. 235. 

 * Ibid., p. 236. 



