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Show 242 THE DESCENT OF MAN •. PARTL rejected chiefly because the distribution of the variously c~loured races, most of whom must have long inhabited their present homes, does not coincide wit.h corresp?ndi. n!Y differences of climate. vV eight must also be g1ven to 0 s11ch cases as that of the Dutch families, wl;w, as we hear on excellent authority/0 have not undergone the least change of colour, after residing for three ce~turies in South Africa. The uniform appearance m various parts of the world of gypsies and Jews, though the uniformity of the latter has been somewhat exaggerated, 41 is likewise an argument on the same side. A very damp or a very dry atmosphere has been supposed to be more influential in modifying the colour of the skin than mere heat; but as D'Orbigny 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.42 Various facts, which I have elsewhere given, prove that the colour of the skin and hair is sometimes correlated in a surprising manner with a complete immunity from the action of certain vegetable poisons and from the attacks of certain parasites. Hence it occurred tome, that negroes and other dark races might have acquired their dark tints by the darker individual& escaping during a long series of generations from the deadly influence of the miasmas of their native countries. I aftenrards found that the same idea had long ago ~ 0 Sir Andrew Smith, as quoted by Knox, 'Races of 1\fan,' 1850,. p. 473. 41 See De Quatrefages on this head,' Revue des Cours Scienti:fiques,' Oct. 17, 1868, p. 731. 4~ Livingstone's 'Travels and Researches inS. Africa,' 1857, p. 3381 329. D'Orbigny, as quoted by God.ron, 1 Do l'Espcce,' vol. ii. p. 266~ CHAP. VII. THE RACES OF MAN. 243 occurred to Dr. vVells.43 That negroes, and even mulattoes, are almost completely exempt from the yellowfever, which is so destructive in tropical America, has long been known.44 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 return home invalided.45 This immunity in the negro seems to be partly inherent, depending on some unknown peculiarity of constitution, and partly the result of acclimatisation. Pouchet 46 states that the negro regiments, borrowed from the Viceroy of Egypt for the Mexican war, which had been recruited near the Soudan, escaped the yellow-fever almost equally well with the negroes originally brought from various parts of Africa, and accustomed to the climate of theW est Indies. That acclimatisation plays a part is shewn by the many cases in which negroes, after having resided for some time in a colder climate, have become to a certain extent liable to tropical fevers.47 The nature of the climate under which the white races have long resided, likewise has some influence on them ; for during the fearful epidemic of yellow-fever in Demerara during 1837, Dr. Blair found that the death-rate of the immigrants was proportional 43 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 colour correlated with constitutional peculiarities are given in my 1 Variation of Animals under Domestication,' vol. ii. p. 227, 335. 44 See, for instance, Nott and Gliddon, 1 Types of Mankind,' p. 68. 45 Major Tulloch, in a paper read before the Statistical Society, April 20th, 1840, and given in the 1 Athenreum,' 1840, p. 353. 46 'The Plurality of the Human Race' (translat.), 1864, p. 60. 47 Quatrefages, 'Unite de l'Espece Humaine,' 1861, p. 205. Waitz, 'Introduct. to Anthropology,' translat. vol. i. 1863, p. 124:. Living· stone gives analogous cases in his' Travels.' R 2 |