8 build: definition and ontogeny. 



B. THE ONTOGENY OF BUILD. 



From the time of fertilization of the egg it proceeds on its course 

 of development directed by its "hereditary factors/' but modifiable 

 by the conditions offered by the environment. Thus is determined the 

 weight of the baby at birth, and thus the build of the later stages to 

 maturity are directed. It has seemed useful to measure the changes 

 in build from birth to maturity, using the method of measuring build 

 during development described in an earlier section (p. 4). 



Materials and Methods. 



The materials available for such a study are considerable and may 

 be drawn from a large number of different nationalities. A selection 

 had to be made from this material; there were chosen the best avail- 

 able series from those nationalities most representative of the popu- 

 lation of the United States, considering the diversity of its European 

 origin. Two sets of data were utilized: first, collections of measure- 

 ments made on males from 1 year to 21 years ; second, some collections 

 from children of both sexes from birth to 1 year of age. 



The first collection of data is gathered from nine sources, listed 

 below. The data used are given in detail in table 3, which shows the 

 number of individuals measured by each observer at each age, the 

 average relative chest-girth at that age, and the average, for each age. 

 of the different averages of the relative chest-girths formed by each 

 observer. These averages are not weighted, since the racial stocks 

 measured by the different observers differed. The average of each 

 observer has therefore to be considered as a unit of nearly equal value 

 with that of any other (table 3). 



1. Quetelet (1870) data. As Quetelet's original book was not available, 

 the data reprinted in Bardeen (1920, p. 544) were used. Quetelet measured 

 10 persons at each age from 1 to 20 years (and older). He selected his 

 subjects with good judgment and the resulting curve of varying build is 

 remarkably smooth. The subjects were doubtless Belgians. 



2. Weissenberg (1911) data. These were gathered by observations on 

 South Russian Jews. The numbers observed ranged from 15 males at birth 

 to about 40 to 100 at later ages. This series is of especial value because 

 such large numbers of individuals of each age were measured and because 

 in it are considered only children as near as possible to their birthdays; 

 that is, as 2 or 3 year old children were taken those of exactly 2 or 3 years 

 ± 2 months; as 4, 5, and 6 year olds, 4, 5, and 6 years ± 3 months; as 7 and 

 8 years, 7 or 8 years ± 4 months. For older children the even year =fc 5 

 months was taken. The measurement was taken at the line of the nipples 

 and below the lower apex of the scapulae; chest apparently at rest. 



3. Benedict and Talbot (1920) data. These were gathered from healthy 

 children of Boston, Massachusetts. Girth was taken at the nipples, in a 

 quiescent condition. The number of individuals considered at each age is 

 small (1 to 9) , but the data are precious, because so few have been published 

 for the period 2 to 5 years. 



