DURING POST-NATAL DEVELOPMENT. 



523 



height-weight-index growth-curve which we have chosen as typical of the healthy 

 American male baby. Up to the seventh month (the period of infancy as defined 

 above) it represents an index of 0.918. Here we have illustrated rapid growth in 

 length and weight without change in the proportions of the body. While we thus 

 represent the type-curve for this period as a straight line we recognize, of course, 

 that there are some changes during this period in the general proportion of the body 

 in all individuals and marked fluctuations in many individuals. Further data will 

 enable the construction of a more accurate type-curve for this period, but the period 



CHART B. Weigh! for height curves at birth and six months of age. 



TypicaJ 

 growth cun' 



is undoubtedly marked by relatively slight change in bodily proportions. The 

 data of Ahlfeld (1871) indicate a similar condition and a similar index during the 

 latter part of fetal life. 



In the report of the British Anthropometric Committee (1883), drawn up by 

 Roberts and Rawson, a table is given showing the average weight for a given 

 stature in inches for each sex at birth based on a study of 451 males and 466 females. 

 A curve based on the data for the male infants is designated Roberts, new-born 

 boys, in chart B. It will be noted that the shorter infants are here markedly heavier 



