(71.) _Extent of the Alterations produced by Climate._--Changes occasioned by climate are always limited to the fleece, horns, and disposal of the fat, and never extend to those parts, on the permanence of which the animal depends for its station in the scale of being, as the feet, teeth, and digestive organs. In tropical countries we find the fleece approaching more to hair than wool, as in the sheep of Thibet, so celebrated for the silky nature of their coat. Burchell remarks, that the skins he brought from the Cape of Good Hope were often taken for those of an unknown quadruped, from the _furry_ nature of their wool, if such it can be called, and thinks it is owing as much to the pasture, which is well adapted for giving these animals a soft and useful _fur_, though not suited, like New South Wales, for the growth of the finest wool, and that the colony might turn this to great advantage. In cold regions the hairy covering is more developed and fully coarser, but always mingled with a proportion of hard rough wool. The influence of climate on portions of the fleece and skin is well illustrated by circumstances which have occurred in Galloway, even within the limits of our traditionary writings.[11] The native sheep of the Highlands of that district is supposed to have been a small, handsome, _white-faced_ breed; at least so thinks John MacLellan, who wrote an account of Galloway in 1650, from the wool being much praised, and eagerly bought up by merchants, which would not have been the case if taken from the _black-faced_ animal; yet how happens it that at present the native breed exists only in the lower parts of Kirkcudbrightshire, the high country exhibiting _black-faced_ sheep, which, after every trial, have been found best adapted to the climate, and pasture of the moors and Highlands; while Chalmers owns that it has not been ascertained when or whence this hardy breed were brought to their present locality? Why, it is tolerably plain, that though the _white-faced_ sheep might be placed there originally, yet they would speedily lose every trace of their origin, and become _black-faced_ when placed on a hilly country, and subjected to the slow but certain influence of peculiar food and climate. [11] Chalmers' Caledonia--Article, Galloway. Mr Culley imagines, that the dun-faced sheep were the earliest tenants of the Scottish hills, but so far as my researches extend, that supposition is entirely contradicted. Chalmers remarks, that the black-faced animals superseded the goats, which were at one time a source of subsistence to the farmers, and it is exceedingly probable, that as the old white-faced began to change their appearance, and became gradually able to withstand the rigours of a mountain fare, and winter under a dun skin, and short rough wool, so would they recommend themselves as the best of all stock to the hard-driven agriculturalist.