196 PHYSICAL INVESTIGATION. [PART I. 



assertion, that before the present human race there existed 

 one resembling the ape, supported by the mystical doctrine of 

 the spontaneous extinction of lower human types, remains 

 without the least scientific proof. Two other assertions of 

 Smith still require investigation, namely, that each of the 

 principal types of mankind (European, Mongol, and Negro), 

 can only perpetuate themselves in their native country, and 

 that each must be considered as a distinct species, from which 

 new types issue by intermixture. ^e shall best consider 

 these views in connection with those of another naturalist. 



Agassiz has given a peculiar support to the theory of the 

 specific differences of the chief types through the influence of 

 climate. 1 His mode of treating this subject is in the main not 

 original, but is similar to that of Swainson 2 who, without him- 

 self deciding on the unity of mankind, assumes six zoological 

 provinces, apparently agreeing with the regions occupied by 

 the various races. They are the following: 1. Europe with 

 Asia Minor, and the coasts of the Mediterranean; 2. Asia be- 

 yond the Ural ; 3. America (all these three with three, the latter 

 with a fourth, problematical subdivision in the extreme south) . 

 4. Africa south of Sahara, the third subdivision of which 

 (South Africa and Madagascar) passes into the 5th. Australia 

 (with New Holland as centre) ; 6. the north of the old and new 

 world. The corresponding human races would be : the Cauca- 

 sian, Mongolian, American, the Negro, the Malay, and the so- 

 called Hyperborean. Agassiz has the following observations 

 on this theory. 



The boundaries of the zoological and botanical provinces, 

 correspond generally with the distribution of the so-called races 

 of mankind. But the species of animals and plants is originally 

 different in each of these provinces ; and even in those where 

 the differences are but slight, no common descent can be 

 assumed if they belong to different provinces, because no 

 species passes across its limits into another province, but (as 

 can be proved by many examples) keeps within its native soil. 

 Hence we must assume, not one but several centres of creation 



1 " Christian Examiner," Boston, July 1850, and in Nott and Gliddon. 



2 " Treatise on the geography and classification of animals," London, 1835. 



