METABOLISM AS AFFECTED BY GROWTH. 



149 



CALORIES PER KILOGRAM OP BODY-WEIGHT PER 24 HOURS REFERRED TO AGE (oiBLS). 



Our observations on girls at different ages, being practically as 

 numerous as those of boys, allow us to study the caloric output per 

 kilogram of body-weight as referred to age. In figure 31 we have 

 plotted the individual points for all of our girls on this basis. The 

 striking scatter of all these points makes it extremely difficult to lay 

 on anything in the nature of a smoothed curve that could be considered 

 justifiable. From the concensus of opinion of five observers, a curve 

 has been sketched which indicates nothing more than a general trend. 



Cals. 



CALORIES PER KILO. REFERRED TO AGE. 



GIRLS. 



FIG. 31. Basal heat production of girls per kilogram of body-weight per 24 hours 



referred to age. 



Points inclosed in squares signify puberty established. For No. 239 compare point inclosed in 

 diamond (prepubescence) with point inclosed in square at 12 years 1 month (puberty). 



During the first six months on the average there is a somewhat 

 lower metabolism per unit of weight than appears later, with the 

 highest values occurring at about one year. The general form of 

 the curve is not unlike that in figure 30 for boys. Although it is 

 hardly the place to emphasize a sexual differentiation, it is worth 

 while indicating here that with boys the highest values lie at 64 calories, 

 while with girls there are six of the individual points which lie higher 

 than 64 calories, practically all of them being inside the first year. 



When it is remembered that the element of weight is in large part 

 removed by this comparison, one is impressed by the wide variations 

 to be found in the calories per kilogram of body-weight of children of 

 various ages. For example, at or about the age of 1 year we find 

 variations ranging from 42 to 70 calories, and it is only after the age 



