Nor does domestication affect all animals and fowls equally; compare the camel, ass, and deer, with the hog and dog; the Guinea fowl, pea fowl, and goose, with pigeons, turkeys, and common fowls. In fact, no one animal can be taken as an analogue for another: each has its own physiological laws; each is influenced differently and in different degrees by the same external influences. How, then, can an animal be taken as an analogue for man? We have also abundant authority to show that all wild species do not present the same uniformity in external characters. "All packs of American wolves usually consist of various shades of color, and varieties nearly black have been occasionally found in every part of the United States.... In a gang of wolves which existed in Colleton District, South Carolina, a few years ago (sixteen of which were killed by hunters in eighteen months), we were informed that about one-fifth were black, and the others of every shade of color, from black to dusky gray and yellowish white."--AUDUBON & BACHMAN, 2d Amer. ed., vol. ii. pp. 130-1. Speaking of the white American wolf, the same authors say:-- "Their gait and movements are precisely the same as those of the common dog, and their mode of copulating and number of young brought forth at a litter, are about the same." (It might have been added that their number of bones, teeth, whole anatomical structure are the same.) "The diversity of their size and color is remarkable, no two being quite alike."... "The wolves of the prairies ... produce from six to eleven at a birth, of which there are very seldom two alike in color."--_Op. cit._, p. 159. "The common American wolf, Richardson observes, sometimes shows remarkable diversity of color. On the banks of the Mackenzie River I saw five young wolves leaping and tumbling over each other with all the playfulness of the puppies of the domestic dog, and it is not improbable they were all of one litter. One of them was pied, another black, and the rest showed the colors of the common gray wolves." The same diversity is seen in the prairie wolf, and naturalists have been much embarrassed in classifying the various wolves on account of colors, size, &c. All this is independent of _domestication_, and shows the uncertainty of analogues; and still it is remarkable that though considerable variety exists in the native dogs of America in color and size, they do not run into the thousand grotesque forms seen on the old continent, where a much greater mixture exists. The dogs of America, like the aboriginal races of men, are comparatively uniform. In the East, where various races have come together, the men, like the dogs, present endless varieties, Egypt, Assyria, India, &c.