Xvi HISTORICAL SKETCH. 



Society * An Account of a White female, part of whose 

 skin resembles that of a Negro '; but his paper was not 

 published until his famous ' Two Essays upon Dew and 

 Single Vision' appeared in 1818. In this paper he 

 distinctly recognises the principle of natural selection, 

 and this is the lirst recognition which has been indi- 

 cated; but he applies it only to the races of man, and 

 to certain characters alone. After remarking that ne- 

 groes and mulattoes enjoy an immunity from certain 

 tropical diseases, he observes, firstly, that all animals 

 tend to vary in some degree, and, secondly, that agri- 

 culturists improve their domesticated animals by selec- 

 tion; and then, he adds, but what is done in this latter 

 ease "by art, seems to be done 'with equal efficacy, 

 though more slowly, by nature, in the formation of 

 varieties of mankind, fitted for the country which they 

 inhabit. Of the accidental varieties of man, which 

 would occur among the first few and scattered inhabi- 

 tants of the middle regions of Africa, some one would 

 be better fitted than the others to bear the diseases of 

 the country. This race would consequently multiply, 

 while the others would decrease; not only from their 

 inability to sustain the attacks of disease, but from their 

 incapacity of contending with their more vigorous neigh- 

 bours. The colour of this vigorous race I take for 

 granted, from what has been already said, would be 

 dark. But the same disposition to form varieties still 

 existing, a darker and a darker race would in the course 

 of time occur: and as the darkest would be the best 

 fitted for the climate, this would at length become the 

 most prevalent, if not the only race, in the particular 

 country in which it had originated." He then extends 

 these same views to the white inhabitants of colder 



