546 



HUMAN BIOLOGY 



fertile group with which we are deahng, was nearly in simple 

 proportion to the size of the groups themselves, having 

 regard to age, and when the Professional service group is 



40 



■45 

 40 

 3S 

 30 

 Z5 

 ZO 

 15 

 10 

 5 



I Population \^More -fertile Families || Children 



ill B-^ it] 



Professional Clerical Trade Domestic Public Transporiat'ion Manufacture Agriculture Mining 

 Fig. 1 1. Graph of the three percentage columns of Table vii. 



taken as i.oo in each instance. But in the three occupational 

 classes Manufacturing, Agriculture, and Mining the case 

 is quite different. Whereas there were 3.22 times as many 

 males aged forty-five and over in the Manufacturing class 

 in 1920 as in the Professional class, the females mated to 

 males in the Manufacturing class had produced, up to and 

 including 1923, 8.9 times as many children as had the 

 females mating to the corresponding portion of the males in 

 the Professional class, in the same period. In 1920 there 

 were 3.04 times as many males forty-five years of age and 

 over in the Agriculture class as they were in the Professional. 

 But the total production of children up to and including 1923, 

 by the more fertile moieties in the classes, had been 11.86 

 times as great in the Agriculture class as it had been in the 

 Professional. In the Extraction of minerals class there were 

 only 0.27 as many males forty-five years of age and over as 

 there were in the Professional class. But the production of 

 children up to 1923 had been 1.34 times as great in the 

 former class as in the latter. 



So far we have considered the populations, more fertile 

 families, and total children ever born, of th^ several 

 occupational classes, only in relation to the Professional 

 group taken as i.oo. This procedure gives a correct picture 

 of the situation so far as strictly interclass comparisons of 



