The color of an animal is, to some extent, a criterion of the purity of its breed. Roan is a favourite hue with the breeders of Shorthorns. There have been celebrated sires and dams of that breed perfectly white; but that color, or rather absence of color, is now somewhat unpopular, partly from the idea that it is a sign of weakness of constitution--a notion for which there appears to me to be no foundation in fact. The slightest spot of black, or even a very dark shade, is regarded to be a blemish of the most serious kind when observed on the pelt of a Shorthorn. The Herefords are partly white, partly red; the Devon possesses in general a deep red hue; the Suffolks are usually of a dun or faint reddish tint; the Ayrshires are commonly spotted white and red; and the Kerrys are seen in every shade between a jet black and a deep red. Uniformity in color would be most desirable in the case of each variety, and this object could easily be attained if breeders devoted some attention to it. _The Form of Animals._--The functions of an animal are arranged by Bichat, an eminent physiologist, into two classes--those relating to its nutrition, and those exhibited by its muscular and mental systems. The first class of functions comprise the _vegetative_, or organic life of the animal, and the second class constitute its _relative_ life. Adopting this arrangement, we may say, then, that those animals in which the vegetative life is far more energetic than the relative life are best suited for the purposes of the feeder. In tigers, wolves, and dogs the relative life predominates over the vegetative; the muscles are almost constantly in a high degree of tension, and the processes of nutrition are in constant requisition to supply the waste of muscle. On the other hand, in oxen, sheep, and pigs, at least when in a state of domesticity, the muscles are not highly developed; they do not largely tax the vegetative processes, and, consequently, the substances elaborated under the influence of the vegetative life rapidly increase. The form of an animal is therefore mainly determined by the activity of its relative life. In a greyhound, the nervous power of which is highly developed, the muscles are large and well-knit, the stomach, intended for the reception of concentrated nutriment only, is small, and the lungs are exceedingly capacious. In such an animal the arrangements for the rapid expenditure of nervous power must be perfect. It is not merely necessary that its muscles should be large and powerful, its lungs must also admit of deep inspirations of oxygen, whereby the motive power wielded by these muscles may be rapidly generated. Now, an animal exactly opposite in organisation to the greyhound would, according to theory, be just the kind to select for the production of meat. The greyhound and the horse expend all their food in the production of motive power; the ox and the sheep, being endowed with but a feeble