METABOLISM AS AFFECTED BY GROWTH. 153 



smoothed curves. Of importance, however, is the fact that the 

 values obtained by Sonden and Tigerstedt with two sleeping boys 

 11 and 12 years old, respectively, and indicated in figure 33 by small 

 crosses, lie close to our line. This explains not only why our values 

 are lower than the other values found by Sonden and Tigerstedt, as 

 well as the composite values derived by Carl Tigerstedt from the 

 observations of Hellstrom, Rubner, von Willebrand, and Sonden and 

 Tigerstedt, but likewise, we believe, why they are lower than the 

 results of the observations of Magnus-Levy and Talk, Du Bois, and 

 others. When the experimental conditions under which the early 

 investigations were made more nearly approach basal requirements 

 the values are found to be more in line with our smoothed curve. As 

 will be seen later (page 209), while we must disregard in large measure 

 the earlier work as a standard for basal metabolism, these results 

 have a great practical value for estimating the probable 24-hour total 

 daily requirements of the growing, active child. The two series thus 

 supplement each other perfectly. 



METABOLISM PER UNIT OF BODY- WEIGHT REFERRED TO WEIGHT. 



In referring the metabolism of children to age, undue stress is laid 

 upon the age element; from the earlier analysis of the metabolism of 

 adults of different ages, we have every reason to believe that, while 

 the age factor is by no means to be ignored, it does not in any way 

 compare with the weight factor. With youth, gross differences in 

 metabolism are noted with variation in age, but these differences may 

 in large part be ascribed to the concomitant weight changes, since a 

 child changing in age is likewise changing in weight. Theoretically, 

 at least, a more logical comparison of the metabolism of different 

 children is not upon the basis of age, but upon weight. The weight 

 element is in part removed by computing the calories per kilogram of 

 body-weight. Even then, strictly speaking, the comparison still is 

 best made with children of various weights rather than of various 

 ages. From the analysis of the charts in figures 22 to 32, it is seen 

 that in general the pictures of the metabolic changes for the various 

 weights are not unlike those for age, and hence we are prepared to find 

 the curves for the calories per kilogram of body-weight referred to 

 body-weight somewhat similar to those in which these values are 

 referred to age. 



Our values for boys have been plotted in figure 35 and a smoothed 

 curve sketched to indicate approximately the general trend. The 

 very wide scatter of the points, particularly below 18 kg. in weight, 

 is worthy of special notice and is fully in accordance with variations 

 noted in the age charts. It seems reasonably clear that at the weights 

 under 6 or 7 kg. there still is a tendency for the metabolism to be 

 somewhat lower per kilogram than a little later. Hence we feel that 



