38 MAN THE ANIMAL 



precisely the rate at which this process is occurring. But an in- 

 teresting local indication about the matter is seen in the fact that 

 in 1933, of the 1,763,351 white babies born alive in the United 

 States to parents of known birthplace, 160,665 or over 9 per 

 cent, were produced by mothers who were born in different 

 countries from those in which the fathers had been born. Now 

 difference in country of birth does not necessarily or universally 

 connote difference in race or variety, but in the great majority 

 of cases it does mean that the two parents represented considera- 

 ble differences in genetic as well as social backgrounds. If in the 

 computation we consider only specifically named parental coun- 

 tries of birth, the percentage rises to 10.1. So that, even in 1933 

 in this country where immigration has for some years been 

 greatly restricted by law, something of the order of a tenth of 

 the white births each year, as a minimum, are contributions to the 

 levelling process of random redistribution of genes. The figures 

 are for the whole of continental United States and therefore 

 include those parts of the deep South where "foreigners" have 

 even yet penetrated but little as compared with the heavily 

 urbanized and industrialized northern and eastern sections of 

 the country. But, in any case, the precise figure is of no great 

 moment. The important thing is that in one of the larger coun- 

 tries of the world the process of amalgamation of human group 

 differences by breeding goes on steadily year by year to a sig- 

 nificant degree. 



The social consequences of this process are highly important, 

 and bound to be increasingly so the longer it is continued. Con- 

 sider war as a single example. As has been elsewhere pointed 

 out (Pearl, Studies in Humi.an Biology y 1924, pp. 542-3): "In 

 general, why men deliberately plan wars is because they are 

 different biologically, in structure, habits, mental outlook, 

 thought, or other ways, and wish to preserve intact their differ- 

 entiations. The more truly conscious they become of these group 

 differences, the more likely they are to fight as groups. As soon 

 as they attain the first glimmerings of such consciousness they are 

 apt to see, or to think they see, something in the behavior of their 



