THE RAGES OF MAN. 189 



CHAPTEE VII. 



OK THE KACES OF MAN. 



The nature and value of specific characters Application to the 

 races of man Arguments in favor of, and opposed to, ranking 

 the so-called races of man as distinct species Sub-species 

 Monogenists and polygenists Convergence of character 

 Numerous points of resemblance in body and mind between the 

 most distinct races of man The state of man when he first 

 spread over the earth Each race not descended from a single 

 pair The extinction of races The formation of races The 

 effects of crossing Slight influence of the direct action of the 

 conditions of life Slight or no influence of natural selection 

 Sexual selection. 



IT is not my intention here to describe the several so- 

 called races of men; but I am about to inquire what is the 

 value of the differences between them under a classificatory 

 point of view and how they have originated. In determin- 

 ing whether two or more allied forms ought to be ranked 

 as species or varieties, naturalists are practically guided by 

 the following considerations, namely, the amount of differ- 

 ence between them, and whether such differences relate to 

 few or many points of structure, and whether they are of 

 physiological importance; but more especially whether they 

 are constant. Constancy of character is what is chiefly 

 valued and sought for by naturalists. Whenever it can be 

 shown, or rendered probable, that the forms in question 

 have remained distinct for a long period, this becomes an 

 argument of much weight in favor of treating them as 

 species. Even a slight degree of sterility between any two 

 forms when first crossed, or in their offspring, is generally 

 considered as a decisive test of their specific distinctness; 

 and their continued persistence without blending within 

 the same area, is usually accepted as sufficient evidence, 

 either of some degree of mutual sterility, or in the case of 

 animals of some mutual repugnance to pairing. 



Independently of fusion from intercrossing, the complete 

 absence, in a well-investigated region, of varieties linking 



