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PAKT II. 



PSYCHOLOGICAL INVESTIGATION. 



IP the examination of the physical peculiarities of the races 

 of mankind had irresistibly led to the result, that the question 

 as regards the unity of mankind must be answered in the 

 negative, we might have been relieved of the necessity of in- 

 quiring into the psychical endowments of the various races ; 

 or we might have simply endeavoured to ascertain whether the 

 specific physical diversities corresponded to the differences in 

 psychical manifestations. But the psychological investigation 

 becomes highly important, if not indispensable, for the solu- 

 tion of the chief question when we find that, though anatomy 

 and physiology furnish us with stronger grounds in favour of 

 the unity of mankind, as a species, than the arguments ad- 

 duced for the opposite theory, they are of such a nature 

 that they cannot be considered as decisive. Again, however 

 conclusive the physical arguments in favour of unity might be, 

 they would lose their validity if it could be established, that 

 there existed permanent psychical differences, presenting im- 

 passable barriers to the development of individual races. 



The psychological aspect of the question has not, it is true, 

 been entirely overlooked; but its importance has either not 

 been sufficiently estimated, or it has been treated with a 

 superficiality that would surprise us, if "the reason why" 

 were not so clear. If it be somewhat difficult to arrive 

 at a just estimation of the mental capacity of individuals 



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