246 THE DESCENT OF MAN. Part I. 



latter agency, for there is good reason to believe that 

 some inherited effect is thus produced. 50 



We have seen in our third chapter that the condi- 

 tions of life, such as abundant food and general comfort, 

 affect in a direct manner the development of the bodily 

 frame, the effects being transmitted. Through the 

 combined influences of climate and changed habits of 

 life, European settlers in the United States undergo, as 

 is generally admitted, a slight but extraordinarily rapid 

 change of appearance. There is, also, a considerable 

 body of evidence shewing that in the Southern States 

 the house-slaves of the third generation present a 

 markedly different appearance from the field-slaves. 51 



If, however, we look to the races of man, as distri- 

 buted over the world, we must infer that their charac- 

 teristic differences cannot be accounted for by the 

 direct action of different conditions of life, even after 

 exposure to them for an enormous period of time. The 

 Esquimaux live exclusively on animal food; they are 

 clothed in thick fur, and are exposed to intense cold 

 and to prolonged darkness ; yet they do not differ in 

 any extreme degree from the inhabitants of Southern 

 China, who live entirely on vegetable food and are ex- 

 posed almost naked to a hot, glaring climate. The un- 

 clothed Fuegians live on the marine productions of their 

 inhospitable shores ; the Botocudos of Brazil wander 



50 See, for instance, Quatrefages ('Eevue des Cours Scientifiques,' 

 Oct. 10, 1868, p. 724) on the effects of residence in Abyssinia and 

 Arabia, and other analogous cases. Dr. Eolle ('Der Mensch, seine 

 Abstammung,' &c, 1865, s. 99) states, on the authority of Khanikof, 

 that the greater number of German families settled in Georgia, have 

 acquired in the course of two generations dark hair and eyes. Mr. D. 

 Forbes informs me that the Quichuas in the Andes vary greatly in 

 colour, according to the position of the valleys inhabited by them. 



51 Harlan, ' Medical Researches,' p. 532. Quatrefages (' Unite' de 

 l'Espece Humaine,' 1861, p. 128) has collected much evidence on this 

 head. 



