188 THE DESCENT OF MAN. 



followed by almost all anthrox)ologists.°= This view has been 

 rejected chiefly because the distribution of the variously col- 

 ored races, most of whom must have long inhabited their present 

 homes, does not coincide with corresponding differences of cli- 

 mate. Some little weight may be given to such cases as that of 

 the Dutch families, who, as we hear on excellent authority," 

 have not undergone the least change of color after residing for 

 three centuries In South Africa. An argument on the same side 

 may likewise be drawn from the uniform appearance in various 

 parts of the world of gipsies and Jews, though the uniformity of 

 the latter has been somewhat exaggerated." A very damp or a 

 very dry atmosphere has been supposed to be more influential in 

 modifying the color of the skin than mere heat; but as D'Or- 

 bigny in South America, and Livingstone in Africa, arrived at 

 diametrically opposite conclusions with respect to dampness and 

 dryness, any conclusion on this head must be considered as very 

 doubtful."' 



Various facts, which I have given elsewhere, prove that the 

 color of the skin and hair is sometimes correlated in a surpris- 

 ing manner with a complete immunity from the action of certain 

 vegetable poisons, and from the attacks of certain parasites. 

 Hence it occurred to me, that negroes and other dark races 

 might have acquired their dark tints by the darker individuals 

 escaping from the deadly influence of the miasma of their native 

 countries, during a long series of generations. 



I afterwards found that this same idea had long ago occurred 

 to Dr. Wells."" It has long been known that negroes, and even 

 mulattoes, are almost completely exempt from the yellow fever, 

 so destructive in tropical America."' They likewise escape to a 

 large extent the fatal intermittent fevers, that prevail along at 

 least 2600 miles of the shores of Africa, and which annually 

 cause one-fifth of the white settlers to die, and another fifth to 



=2 Pallas, 'Act. Acad. St. Petersburg," 1780, part ii. p. 69. He was fol- 

 lowed by Budolphi, in his 'Beytrage zur Anthropologie,' 1812. An ex- 

 cellent summary of the evidence is given by Godron, 'De I'Espeoe,' 

 1859, vol. ii. p. 246, &c. 



=2 Sir Andrew Smith, as quoted by Knox, 'Races of Man," 1850, p. 473. 



" See De Quatrefages on this head, 'Revue des Cours Scientifiquee,' 

 Oct. 17, 1868, p. 731. 



^ Livingstone's 'Travels and Researches in S. Africa,' 1857, pp. 338, 

 329. D'Orbigny, as quoted by Godron, 'De I'Bspece,' vol. ii. p. 266. 



™ See a paper read before the Royal Soc. in 1813, and published in 

 his Essays in 1818. I have given an account of Dr. Wells' views in 

 the Historical Sketch (p. xvi.) to my 'Origin of Species.' Various 

 cases of color correlated with constitutional peculiarities are given in 

 my 'Variation of Animals under Domestication,' vol. ii. pp. 227, 335. 



"' See, for instance, Nott and Gliddon, 'Types of Mankind,' p. 68. 



