INFLUENCE OF SEX ON METABOLISM. 



179 



respectively, and here superimposed. In this comparison of total 

 calories to weight, we find that the absence of a real sexual difference 

 shown with new-born infants 1 persists until about the weight of 11 kg., 

 and that subsequently there is a tendency for the boys to have a 

 somewhat higher metabolism than girls of the same weight, the line 

 for boys being perceptibly above that for girls. 



Cals. 



TOTAL CALORIES REFERRED TO WEIGHT. 



FIG. 48. Comparison of basal heat production of children and adults per 24 hours 



referred to body-weight. 



Attention should here be called to the fact that in the preliminary 

 presentation of this material, 2 a somewhat different relationship 

 between the curves for boys and girls was noted in that the curve for 

 girls rose above that for boys at the weight of 35 kg. Subsequent 

 revision and elision has justified the caution pronounced at that time 

 to the effect that the number of individuals measured at the higher 

 weights were, with both sexes, too few to justify sweeping conclusions. 

 As here shown in the latest and more complete analysis of our material, 

 we have clear evidence of a sexual differentiation in basal metabolism 

 exhibited above 11 kg., in which the boys show persistently a somewhat 

 higher metabolism than girls of the same weight. 



Since a comparison of the metabolism of youth and adults is of 

 general interest, the trends of the metabolism on 'the basis of total 

 calories referred to weight are also shown in figure 48 for men and 

 women. These curves will be given special discussion later. 



A comparison may also be made of the two curves for boys and 

 girls in figures 38 and 39, in which the total heat was referred to actual 

 measurements of the body-surface by the Du Bois method. This 



1 Benedict and Talbot, Carnegie Inst. Wash. Pub. No. 233, 1915; Harris and Benedict, Carnegie 



Inst. Wash. Pub. No. 279, 1919, p. 219. 



2 Benedict, Boston Med. and Surg. Journ., 1919, 181, p. 107. 



