762 



THE POPULAR SCIENCE MONTHLY. 



women have no children, only 3'5 per cent of the half bloods are 

 childless. The proportionate number of half bloods who have 

 one, two, three, four, or five children is smaller than the corre- 

 sponding number of Indian women, while many more half-blood 

 women than full-blood women have had from six to thirteen 

 children. This distribution is shown clearly in Fig. 1, which 



1 2 3 4 5 6 7 8 9 10 11 12 13 11 15 16 17 18 19 



no. of children 

 Fig. 1. Number of Children of Indian Women and of Half-blood Women. 



represents how many among each one hundred women have a 

 certain number of children. The facts disclosed by this tabula- 

 tion show that the mixed race is more fertile than the pure stock. 

 This can not be explained by a difference of social environment, 

 as both groups live practically under the same conditions. It also 

 appears that the small increase of the Indian population is almost 

 entirely due to a high infant mortality, as under better hygienic 

 surroundings an average of nearly six children would result in a 

 rapid increase. It is true, however, that a decrease of infant 

 mortality might result in a decreased birth rate. 



Among the Indians of the Pacific coast the infant mortality is 

 also very great, but we find at the same time a still larger pro- 

 portion of women who bear no children. 



It is of some interest to note the average number of children 

 of women of different ages as indicating the growth of families. 

 Among the Indians there is an average interval of four years and 

 a half as shown in the following table which, however, must 

 not be confounded with an average interval between births : 



Indian women 20 years of age have on the average 1 child. 

 " " 25 " " " " 2 children. 



(( (1 OO 11 11 11 11 Q 11 



(I 11 QQ 11 11 II 11 ^ 11 



(I 11 QQ II 11 11 It g II 



Among the half bloods the interval is shorter, but the number of 

 available observations is insufficient for carrying out the com- 

 parison in detail. 



