132 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



excluded, even if the full change in weight or age had not been reached. 

 It frequently happened that the full change in weight occurred con- 

 siderably inside of 6 months, and there were also instances when a 

 change in age of 6 months was not accompanied by a full change in 

 weight. By this method, certain children, notably No. 145, appear a 

 number of times upon the charts or scatter-diagrams. For instance, 

 in figure 22, the actual number of boys represented is 88, while the 

 number of points plotted is 129. These latter in reality correspond 

 to an equal number of children, since the values found on the same 

 boy are characterized by an appreciable difference in age or weight. 



A biometrical analysis of the data in this series of observations has 

 not been attempted, but on each of the group charts an effort has been 

 made to indicate the apparent general trend of the metabolism on 

 the basis selected for comparison by laying on arbitrarily a smoothed 

 curve. It must be emphasized here that these curves do not represent 

 mathematically determined trends, but are simply sketched from 

 observation of the general distribution of the points. The curves 

 were prepared in the manner previously referred to (see page 37), 

 i. e., five members of the Laboratory staff, accustomed to plots and 

 curves, each drew on a separate sheet of tracing-paper a curve which 

 appeared to him as the most probable. These curves were then com- 

 bined and the line reproduced on the respective charts represents the 

 average of these five plots. While this procedure is admittedly un- 

 mathematical, it serves at least to indicate the general trend of the 

 metabolism. 



All of the precautions cited in our discussion of normality entered 

 into the selection of the individuals and points plotted in these group 

 charts. In a preliminary communication published elsewhere 1 re- 

 garding this study of children during the period of growth, a series of 

 charts was given similar to those in figures 22, 23, 26, 27, 30, 31, 35, 

 36, 42, 43, 45, and 47. The earlier charts differed only in the number 

 of points included, which was somewhat greater than in the present 

 series, as a more rigid exclusion of material was made previous to the 

 final printing here. A comparison of the two sets of smoothed curves 

 brings out the interesting fact that those obtained in the preliminary 

 charting of the values, which were prepared in much the same manner 

 as the later curves, do not differ by a measurable amount from the 

 curves subsequently sketched for the final series. In other words, 

 the eliminations made exclusively on the basis of a more critical exam- 

 ination of the protocols and histories for evidence of the normality 

 of the children have resulted in the removal of an approximately equal 

 number of points above and below the line, so that the position of the 

 line itself is not materially changed. This fact is of considerable 



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



