MAN AND MANKIND 



pressure of centrifugal migrations from eastern into western Europe 

 (Figs. 88a and b). 

 Students ot language have often held the view that some inherent 



64-5 



61-5 



Fig. 88a. — Genetic contour map of Europe to show the geographic gradients in 

 O blood group chromosomes in man. Note that the peripheral distribution of the 

 high populations is as though determined by migration from the east across the 

 central plains. 



property of peoples influences the sounds they use and the changes 

 this use undergoes. We now see that the undefined "Substratum" 

 assumed in linguistics is the aggregate genotypic action of the com- 

 nninity. But it may be asked why such action should change sounds, 



362 



