148 UNITY OF THE SPECIES OP MAN. 



habits, degree of civilization, &c. ; but in the conformation of 

 their bodies, the colours of the surface, the degree in which it is 

 covered with hair, &c. And it conies to be a question of great 

 scientific interest, as well as one that considerably affects the 

 mode in which we view and treat the races that differ from our 

 own, whether they are all of one species, that is, whether they 

 may have all descended from a common stock, or whether they 

 are to be regarded as distinct species, having had an originally 

 distinct parentage. It has been a favourite idea with some 

 of those, who wished to excuse the horrors of slavery or the 

 extirpation of savage tribes, that races thus treated might be 

 considered as inferior species, and as legitimately placed under 

 our dominion ; but this doctrine, which has had its origin in the 

 desire to justify as expedient what could not be defended as 

 morally right, finds no support from scientific inquiries con- 

 ducted in an enlarged spirit. For although it would be easy to 

 select from amongst different races, such as the European, the 

 Guinea-coast Negro, the Kafir, the Tartar, the Malay, the New- 

 Holland, and the American Indian, a set of forms, which, when 

 placed side by side, should present very strongly-marked distinc- 

 tions, yet it would be found that, among all these races, 

 examples would occasionally present themselves, in which these 

 distinctions would be much less obvious. Thus, among the 

 inhabitants of our own country, we may not unfrequently meet 

 with individuals of pure European descent, who have the reced- 

 ing forehead, the woolly hair, the thick lips, and the projecting 

 muzzle of the Negro ; and who want little else than a dark colour 

 in the skin, to have all the chief peculiarities of that race. On 

 the other hand, among some of the Negro races, examples are 

 not unfrequently to be seen, in which the general form of the 

 head and body is that of the European ; the chief difference 

 being in colour. That colour alone cannot be at all relied upon 

 as a distinction, is proved by the fact, that a large number of 

 pigment-cells exists in the skin of all the races of Man ; and that 

 the nature of their secretion, and the consequent hue of the skin, 

 depends greatly upon the degree in which the surface is exposed 

 to light and heat (ANIM. PHYSIOL. 492). Moreover, amongst 



