504 HEIGHT AND WEIGHT IN RELATION TO BUILD 



Curves of linear proportions. In charts I and J, pages 534, 535, we have plotted 

 curves to illustrate the alterations in the relative proportions of various linear 

 measurements to stature which take place during growth in individuals of normal 

 build. Curves of the height- weight index of growth are inserted to illustrate the 

 course of growth of individuals who reach average American stature (63 inches for 

 women, 67.5 to 68 inches for men). A curve (x) is also inserted to illustrate changes 

 in "average transverse diameter" based on the square root of a tenth of the 

 height-weight index of build. Where curves for females depart markedly from those 

 for males the former are indicated by broken lines. The ages given at the bottom 

 on chart I and at the right of chart J represent the approximate age at which an 

 average healthy American reaches the stature shown at the opposite side of the 

 chart. Considerable variation in rapidity of growth may exist without producing 

 marked alterations in the growth-curves shown in the chart. Figures on which 

 these curves are based are given in table K, page 549. 



The curves may be considered as to periods of infancy, childhood, adolescence, 

 and maturity. 



During infancy rapid growth in length may alternate with rapid growth in 

 weight (thickness), but available data seem to show that up to the period of the 

 first dentition the two processes essentially keep pace. We have not many statistics 

 relating to variation in the proportions of the body during early infancy. Weissen- 

 berg (1911) found no essential variations up to the third month after birth. The 

 figures given in table A, based on data from chmid-Monnard, show no uniform 

 change in relative chest-girth until the latter half of the first year, and an examina- 

 tion of the available data relating to the height-weight ratio has led me to similar 

 conclusions. In the absence, therefore, of more definite data I have plotted the 

 curves of linear proportions for infancy on the assumption that there is normally 

 little alteration in relative proportion of the body during this period. There is 

 undoubtedly considerable variation in speed of development. 



During childhood, as we have seen, the proportions of the body are primarily 

 correlated with stature rather than with age. The children of stature 126 to 126.9 

 cm. and 137 to 138.9 cm., in table 10, show no definite correlation between age and 

 weight or chest-girth. The head-girth appears to be slightly smaller in the older 

 than in the younger children. The older boys of stature 126 to 126.9 cm., in table 

 11, show a slightly smaller average weight than the younger (57.2 pounds at 11 

 years as compared with 58.8 pounds at 8 years) and a greater sitting-height (68.6 

 cm. at 11 years as compared with 67.6 cm. at 8 years). The diameters of the head 

 in the 11-year-old group are slightly smaller than in the younger groups. In girls 

 of stature 137 to 138.9 cm. the sitting-height increases progressively from the 10- 

 year-old to the 13-year-old group (from 72 to 73 cm.). The weight is greater in the 

 13-year-old group than in the younger groups (74 pounds as compared with 68.6 

 pounds). No correlation between diameters of the head and age is apparent. 



Variations in bodily proportions, due to acceleration or retardation of the usual 

 course of development during childhood, affect breadths and girths rather than 



