NORMALITY OF CHILDREN STUDIED. 39 



Our laboratory children, whose measurements, together with those 

 of our private-school children, we will now compare with the earlier 

 data we have selected, came from a different social and economic 

 plane of life than our private-school children. This is important to 

 bear in mind in the following comparisons, since it has been shown 

 many times that the development of the child depends on his social 

 surroundings as well as upon his physical well-being. In the several 

 charts now to be considered, since we have but a few scattered obser- 

 vations with our own boys beyond 13 years of age and with our own 

 girls beyond 12 years of age, we have stopped the curves representing 

 our measurements at 13 years for boys and at 12 years for girls. 



RELATIONSHIP BETWEEN BODY-WEIGHT AND AGE WITH BOYS. 



As an index of the state of nutrition of children, the relationship 

 between body-weight and age is perhaps one of the oldest and earliest 

 relationships which have been considered. This ratio of body-weight 

 alone to age obviously does not take into account the very important 

 factor of skeletal growth or length. Still, as it represents one of the 

 earliest relationships utilized, and as it has been the basis of a large 

 number of weight charts of various types, it requires special considera- 

 tion. In figure 3, therefore, we have plotted curves for weight referred 

 to age for boys, representing our own laboratory measurements, those 

 in the two earlier European studies of Quetelet and Schmid-Monnard, 

 the combined Crum-Wood data compiled by Gray, the material from 

 Holt, and the values for the private-school boys measured under our 

 direction. 



The relative positions of these curves are of very great significance. 

 The curves of the two foreign investigators lie throughout practically 

 their entire length measurably below the curve for our laboratory 

 boys, which may undoubtedly in part be explained by the fact that 

 they represent entirely different nationalities. Between themselves 

 they agree reasonably well. Of singular significance is the fact that 

 the combined curve of Crum and. Wood is almost identical with our 

 laboratory curve. It is very important to note that below 4 years of 

 age our laboratory boys measure up essentially to the standard set 

 by this curve, although, as has been pointed out before, Crum's 

 children are considered by him to be somewhat supernormal. A 

 number of our children at this age were, however, the offspring of 

 resident wet-nurses. Holt's curve for private-school boys is measur- 

 ably above the line for our laboratory boys and, indeed, above the 

 continuation of the Crum-Wood curve after the thirteenth year, 

 while the curve for our private-school boys lies even higher than that 

 of Holt. In the case of these private-school children we have distinctly 

 larger and heavier boys for the same age, as is unquestionably shown 



