ENVIRONMENTAL SCHOOL OF SOCIOLOGISTS 119 



The concluding chapter is given to a study of acclimatization in 

 its relation to the problem of the original diversification of races 

 from one parent stock, but especially in its bearing on the 

 colonization of the tropics by the white race. He shows how 

 complex is the question concerning the effect of climate on the 

 human organism as when people migrate from temperate regions 

 to the tropics, and enumerates several disturbing factors that must 

 be eliminated before one can determine this effect, such as the 

 natural change in habits of life in the line of intemperance and 

 immorality that so frequently accompany army life; the effect of 

 race-crossing, choice of foods, differences of occupation with 

 indolence on the one hand and over-exertion on the other. He 

 shows further how a discussion of the effect of climate on the 

 human body must take into consideration the racial element and 

 ethnic peculiarities, certain races being susceptible to certain 

 diseases and immune to others. Having eliminated these dis- 

 turbing elements our author concludes that " the physical ele- 

 ments of climate, ranged in the order of their importance, are 

 humidity, heat, and lack of variety." x 



Physical acclimatization approximating the adaptation of 

 natives, he holds, is a process requiring generations and that ulti- 

 mate racial adjustment to the tropics can be secured, if at all, 

 only by the costly method of trial and selection or by the drift to 

 those regions of individuals and races already by nature and mode 

 of life adapted to such life conditions. He shows that much 

 temporary advantage may be gained by hygienic precautions, but 

 that this does not mean racial acclimatization, and concludes that 

 true colonization of the tropics by the white race is impossible. 2 



As to the question of the original process of racial acclimatiza- 

 tion and diversification, Professor Ripley holds that it was due to 

 spontaneous variation and natural selection and possibly also to 

 ontogenetic variations that somehow became fastened upon the 

 race. 3 



The eminently scientific character of this work and the judicial 

 temper evinced on every page make it apparently above adverse 

 criticism. The various factors that enter into passive socio- 



1 Races in Europe, p. 571- 2 Ibid., p. 584- 3 Ibid., p. 587; cf. pp. 383 f. 



