174 WORLD-POWER AND EVOLUTION 



the head-form of the two parts of the population has everywhere 

 become the same. This can scarcely be the case. In the first 

 place, it is inherently improbable. Jewish men have doubtless 

 had many children by Gentile women, but they are not reckoned 

 as Jews. Jewish girls, on the other hand, are more carefully 

 guarded than Gentile girls, they are married young, and they 

 are strongly imbued with racial prejudices. In the second place, 

 as we have already seen, Fishberg has himself shown that the 

 complexion of the Jewish population gives no hint of much racial 

 mixture in recent times. It is scarcely possible that the form of 

 the heads of a race should change through intermarriage, while 

 their complexion remains unaltered. Hence, in spite of Fish- 

 berg's aspersions upon the women of his own race, there seems 

 reason to believe that the Jews are racially comparatively pure, 

 and that the peculiar facts in regard to the shape of their heads 

 are susceptible of some other explanation. 



This brings us to our third question. Is there any reason to 

 think that the Jews really change in response to their physical 

 environment.? About a decade ago Boas measured some 30,000 

 immigrants and their children in New York City. These measure- 

 ments apparently show that the stature and form of the head 

 among children born to immigrants in this country differ sys- 

 tematically from those of their parents. This conclusion was 

 received with great scepticism. I confess that on reading Boas' 

 preliminary report I shared this feeling. Lately, however, I have 

 read his final report where the full figures are given, and have 

 considered it in the light of the biological experiments described 

 in the preceding chapter. This, together with the facts already 

 outlined as to the Jews in Europe, has led me to revise my opinion. 

 Although Boas' work has been severely and even bitterly criticised 

 I cannot see that the criticism does more than show that in minor 

 details the work might be improved, and that he has sometimes 

 used such phrases as "exceedingly long" when he ought to have 

 said "longer than usual." As he himself says, the investigation 



