unless it be the huge London dray-horse, an animal incapable of working faster than at a foot's pace, and only bred in fact for show and ostentation, not for utility. How it is that an animal sprung from the cross of two species, the sire of which is always greatly smaller than the dam, should be larger than either parent, is one of the unexplained mysteries of breeding; but the mode in which it has been accomplished is no mystery. It is by selecting the very largest and loftiest jacks of the breeds used, in Europe generally, for the saddle, and, in Spain, for the draught of public conveyances and private pleasure carriages, and breeding from them out of the tallest, largest and most roomy mares that can be procured. That such dams should produce hybrids larger than their sires is in the natural course of things, since—as we have pointed out in our previous papers on horse-breeding—it is the mare, furnishing the matrix of the foal, that gives the size and bone to the progeny. But why such mares should produce a much larger offspring, to a male infinitely smaller than themselves in stature, than they would bear to a stallion of their own race, equal or even superior to themselves in height, is not to be accounted for by any known principles of physiology. The fact is, however, as stated, and the result is not desirable. For the mule of increased size appears to approach somewhat nearer to the horse in organization, whereas it is desirable that he should approach nearer to the ass. He is a slower and more sluggish animal, than the smaller breed, is less enduring of labor, less capable of toiling under extraordinary temperatures of heat—which is one of the admitted points of superiority in the mule over the horse—and, being much heavier in proportion, is apt to sink his small, narrow, compressed hoofs far deeper into the ground, where the soil is deep and the roads are sticky and tenacious, while he will
