222 THE DESCENT OF MAN 



CHAPTER VII 



ON THE RACES OF MAN 



The nature and value of specific charaeterg — Application to the races of 

 man — Arguments ia favor of, and opposed to, ranking the so-called 

 races of man as distinct species — Sub-species — Monogenists and polyg- 

 enists — 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 infl,ueuce 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 1 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 determining 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 difference 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. When- 

 ever 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 treat- 

 ing them as species. Even a slight degree of sterility be- 

 tween any two forms when first crossed, or in their offspring, 

 is generally considered as a decisive test of their specific dis- 

 tinctness; and their continued persistence without blending 

 within the same area is usually accepted as sufficient evi- 



