Historical Sketch. xv 





In 1813, Dr. W. C. Wells read before the Koyal 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 first recognition which has been indicated ; but he applies 

 it only to the races of man, and to certain characters alone. After 

 remarking that negroes and mulattoes enjoy an immunity from 

 certain tropical diseases, he observes, firstly, that all animals tend to 

 vary in some degree, and, secondly, that agriculturists improve their 

 domesticated animals by selection ; and then, he adds, but what is 

 done in this latter case " 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 acci- 

 dental varieties of man, which would occur among the first few and 

 scattered inhabitants of the middle region's 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 neighbours. 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 climates. I am indebted 

 to Mr. Rowley, of the United States, for having called my atten- 

 tion, through Mr. Brace, to the above passage in Dr. Well's work. 



The Hon. and Eev. W. Herbert, afterwards Dean of Manchester, 

 in the fourth volume of the * Horticultural Transactions,' 1822, and 

 in his work on the ' Amaryllidacea3 ' (1837, p. 19, 339), declares that 

 " horticultural experiments have established, beyond the possibility 

 of refutation, that botanical species are only a higher and more per- 

 manent class of varieties." He extends the same view to animals. 

 The Dean believes that single species of each genus were created 

 in an originally highly plastic condition, and that these have 

 produced, chiefly by intercrossing, but likewise by variation, all 

 our existing species. 



In 1826 Professor Grant, in the concluding paragraph in his 

 well known paper (' Edinburgh Philosophical Journal,' vol. xiv. 

 p. 283) on the Spongilla, clearly declares his belief that species are 



