Chap. IV.] MANNER OF DEVELOPMENT. 107 



wonderfully complex combination of high faculties, tends 

 to be inherited ; and," on the other hand, it is too certain 

 that insanity and deteriorated mental powers likewise run 

 in the same families. 



With respect to the causes of variability we are in all 

 cases very ignorant ; but we can see that in man as in the 

 lower animals, they stand in some relation with the con- 

 ditions to which each species has been exposed during 

 several generations. Domesticated animals vary more 

 than those in a state of nature ; and this is apparently due 

 to the diversified and changing nature of their conditions. 

 The different races of man resemble in this respect domes- 

 ticated animals, and so do the individuals of the same 

 race when inhabiting a very wide area, like that of 

 America. We see the influence of diversified conditions 

 in the more civilized nations, the members of which be- 

 long to different grades of rank and follow different occu- 

 pations, presenting a greater range of character than the 

 members of barbarous nations. But the uniformity of 

 savages has often been exaggerated, and in some cases can 

 hardly be said to exist. 11 It is nevertheless an error to 

 speak of man, even if we look only to the conditions 

 to which he has been subjected, as "far more domesti- 

 cated " " than any other animal. Some savage races, such 

 as the Australians, are not exposed to more diversified 

 conditions than are many species which have very wide 

 ranges. In another and much more important respect, 

 man differs widely from any strictly-domesticated animal; 



11 Mr. Bates remarks f The Naturalist on the Amazons,' 1863, vol. il 

 p. 159), with respect to +.he Indians of the same South-American tribe, 

 u No two of them were at all similar in the shape of the head ; one man 

 had an oval visage with fine features, and another was quite Mongoliar 

 in breadth and prominence of chee*, spread of nostrils, and obliquity oi ' 

 tyes." 



12 Blunienbach, ' Treatises on Anthropolog.' Eng. translat,, 1805, p. 205. 



