Page:The Zoologist, 4th series, vol 2 (1898).djvu/436

404 and in a creature that had reached the stage of protection afforded by human society, and of aggression by human invention, were outside the ordinary action of natural selection, and became fixed and hereditary. The colour of mankind can in no sense come under the explanations of protective or aggressive resemblance, mimicry, warning or nuptial colouration, &c, and if there are physiological advantages appertaining to the different hues in connection with the climates in which these differently coloured races are found, these advantages are probably incidental to, or rather the effects of, a perfect acclimatization. Perhaps suggestion in this problem is too crude and too early; and, as Tylor cautiously observes, "the great races—black, brown, yellow, white—had already settled into their well-known characters before written record began, so that their formation is hidden far back in the prse-historic period" ; or, as Darwin more precisely writes, "we are far from knowing how long ago it was when man first diverged from the Catarhine stock; but it may have occurred at an epoch as remote as the Eocene period; for that the higher Apes had diverged from the lower Apes as early as the Upper Miocene period is shown by the existence of Dryopithecus." We may well conclude that our earliest progenitors had a more or less hairy covering, but if we are ignorant on this very point, how much less should we speculate on the colour of the same.

There is considerable evidence to be obtained that surface geology induces assimilative colouration in plants as well as in animal life. Thus in the charming 'Letters of Rusticus,' and in connection with the locality of Godalming in Surrey, this passage occurs:—"The soil is a bright red sand, which extends from the chalky range of cold poverty-stricken downs crossing the country