340 PHYSIOLOGY CHAP. 



Of course besides the representatives of these two extreme 

 types there are many persons whose characteristics are mixed 

 (who have chestnut hair, eyes of a darker or lighter shade of 

 brown, and who are mesocephalic and of medium height) because 

 their parents belong to different races. Boas considers that 

 variations in morphological characteristics may be brought about 

 not only by sexual mixture, but also by change of abode. He 

 published recently (1911) an account of the returns of a commis- 

 sion formed in Washington in 1907 for the purpose of studying 

 the conditions of immigrants into the United States, and also 

 the physical changes found in the descendants of immigrants. 

 He studied various physical characteristics (height, length and 

 width of the skull and head, relative cephalic index and facial 

 width) in two types of immigrants, Jews from Eastern Europe, 

 whom he regards as typical representatives of a brachycephalic 

 people, and Sicilians, who are purely dolichocephalic. He extended 

 this comparative analysis to the parent immigrants, their children 

 born during the first few years of their residence in America and 

 ten years later, and the children born in Europe. The result of 

 these investigations, which proves that environment is a factor 

 capable of modifying to a remarkable degree the characteristics 

 of the human form, is as follows : the Jew tends to become taller, 

 his brachycephalic head and broad face to become narrower to 

 approximate, that is, to the dolichocephalic, narrow-faced type. 



In Sicilians, on the contrary, the dolichocephalic type shows a 

 tendency to approximate to the brachycephalic form, by becoming 

 wider in the face. Thus the two extreme types tend towards 

 a single type, i.e. the one prevalent amongst Americans of the 

 present day. The causes of this change must be sought in the 

 environment. 



These results are undoubtedly of the very greatest importance, 

 since they solve one of the most difficult problems of anthropology, 

 namely, that relating to the influence of environment on human 

 types. Serious objections have, however, been made to the con- 

 clusions arrived at by Boas. Sergi (1912) brings two charges of 

 inaccuracy against his work : the first against his method of 

 investigation, which, being based on the comparison of average 

 measurements, does not take into account the special character- 

 istics of the different series; the second to the fact that the 

 existence of a single type characteristic of North Americans has 

 never been proved. 



III. If we would give a brief summary of the scanty records 

 of a physiological order relating to the different human races, we 

 must first of all call to mind the variations which have been noted 

 in the functions of vegetative life, doing so in the order which we 

 have followed throughout the present work. 



There is an ancient belief that the blood of tropical races is 



