EPIDERM OF MAMMALS. 615 



influences. Still more strikingly is this shown by the blackness of 

 the Melanian aborigines of New Guinea, Australia, and Tas- 

 mania, retained from the sixth to the forty-third degree of south 

 latitude ; and especially of those of the outlying islands in prox- 

 imity with others inhabited by the olive-brown Polynesians, whose 

 complexion prevails from lat. 12° S. to 46° S. (New Zealand). 

 But the most instructive example of the closer relationship of 

 tint to race than to climate is afforded by the aborigines of the 

 New World, which hold nearly the same depth of copper-brown 

 or reddish tint, latitudinally from Tierra del Fuego to Hudson's 

 Bay, and longitudinally from the Atlantic to the Pacific. The 

 contrast between the South American Indians and the African 

 Negroes would seem to be decisive against the hypothesis of 

 degrees of solar influence being the causes of degrees of darkness 

 of complexion. 



But there is an element in the problem which ought to be 

 taken into consideration, viz. f time.' If Africa be an older con- 

 tinent than South America, its aborigines may have been sub- 

 jected to solar influences through a longer series of generations. 

 We know not the extent of such series ; some may deem that 

 were the intertropical South American Indians subject to a 

 vertical sun during the long ages of Africa's emersion, they would 

 acquire a darker complexion. 



Climate, however, depends on other influences than sunshine. 

 Degrees of moisture, and whatever influences cause a contrast or 

 gradation of seasons, &c, may have their effects upon com- 

 plexion. Filthy habits, foul air, and bad food, affecting biliary 

 and other secretions, have their share in darkening the skins or 

 sallowing the complexions of the Esquimaux, Fins, and Laps, 

 e.g. as compared with the cleanlier and more healthily living and 

 better nourished Scandinavians residing some degrees further 

 from the pole. But assuming, as the general result of the above 

 survey of human complexions, that such complexions do, in the 

 main, show a certain dependent relationship on solar light and 

 heat, and postulating the effect of long periods of such subjec- 

 tion, we might then be led to conclude the darkest of the 

 intertropical and warm temperate peoples to be the oldest ; that 

 the Melanians, scattered on islands to the east of the Indian 

 Ocean, inhabit relics of a continent as old as, perhaps older than, 

 Africa ; and that the lighter-tinted races on intercalated or 

 contiguous portions of dry land are subsequent immigrations 

 or derivatives from lands less affected by solar influences. On 

 this hypothesis it may be inferred that the deepest-tinted races 



