evolution in this or that respect—in the St. Bernard of size, in the mastiff of strength, in the greyhound of speed, in the bulldog of courage; but on the whole the tendency has been towards retrogression—a retrogression which has operated unequally on the animal parts, physical and mental, and has not infrequently been concomitant with partial evolution. To this unequal retrogression, combined in some cases with limited evolution, is probably to be attributed the diversity of shapes and capacities which characterize our many domesticated breeds. Thus the lapdog and the pug are probably examples mainly of retrogression, not evolution; probably their peculiarities of shape and character are due mainly to the fact that man has permitted or caused retrogression in them in certain directions by selecting the most degenerate individuals in these respects, at the same time that he has checked retrogression, and even caused some evolution, in other directions. Thus also the bulldog has undergone retrogression as regards size, but evolution as regards courage; the greyhound retrogressed as regards strength and power of scent, but evolved as regards speed; the St. Bernard has gained in size, but lost in speed; and so also with all other breeds.
Dogs among civilized peoples especially have often been the mere playthings of their owners, who, taking unconscious advantage of the tendency towards retrogression, have gratified their caprices by rearing many grotesque varieties. As regards the equidæ and bovidæ the case has been entirely different. Reared almost solely for use, their powers and capabilities preserved to the utmost, the domesticated varieties show little retrogression and some evolution. But suppose we selected a number of the swiftest race-horses, or the largest dray-horses, or the best milk-giving cows, and bred from them, selecting afterwards in succeeding
