To support the hypothesis of a single species, it is common to draw an analogy from the different varieties of domestic animals supposed to be of the same species. If there are so many varieties of dogs, horses, hogs, sheep, cattle, etc., it is argued, why may there not be similar varieties of men? It is unwarrantably assumed that the same physiological laws, and the same laws of generation, prevail in the human race as in animals; but without urging this objection, it is not admitted that the animals referred to are from one original stock. Their origin is involved in utter obscurity, and it is just as difficult to prove their origin as it is that of man. Perhaps the greatest variety is amongst dogs; but who can prove that dogs have a common centre of origin? Who can prove, or even make it appear probable, that the dog of the American Indian has the same origin as the European or Asiatic dog? Dr. Nott says: "We have abundant evidence to show that each zoological province has its original dog. Two thousand years before Christ the different varieties of dogs were as well known as to-day." From the monuments of Egypt, “it is no longer a matter of dispute that as far back, at least, as the twelfth dynasty, about 2300 B. C., we find the common small dog of Egypt, the grey-hound, the stag-hound, the turnspit, and several other types." These various types are permanent, and, when pure, remain unchanged in all climates. Tested by permanency of type, the genus

canes consists of several species, many of which, though very similar in many respects, are so different as to be classified into different species, all of which are prolific among themselves to an unlimited degree; but one type is never transformed into another. What is said of the dog holds good of other domestic animals. Two species of the genus horse most remote from each other, the horse and the ass, as is well known, produce an infertile hybrid; but there are several species of asses very similar in general structure, and which breed with one another, but are of different species. Naturalists classify horses into at least six different types. Of our domestic cattle there are several distinct species, of near resemblance, and which breed with perfect freedom. The domestic cattle of Europe consist of numerous varieties, which are traced by the best naturalists to three distinct species.

Nor

It is useless to dwell on certain general resemblances, for nothing of the sort can bridge over a chasm which has existed five thousand years or more between the various species of the human race. is it necessary to dwell on the specific differences of races. Science is unanimous in the conclusion that, on the supposition of a single stock, these varieties could not have originated between the flood and our earliest records. Some suppose that the causes which they imagine might produce such changes operated in that period more rapidly than they ever have

since, as mentioned elsewhere; or that God miraculously, and by direct interposition, degraded about four-fifths of the human race, which is a monstrous proposition, without the color of proof. How, then, are we to account for the different varieties of the genus homo? We conclude, with Agassiz, "that the races cannot have assumed their peculiar features after they had migrated into those countries from a supposed common centre. We must, therefore, seek another explanation. We must remind the reader of the fact that these are not historic races," etc. "We maintain, further," says Prof. Agassiz, "that, like all other organized beings, mankind cannot have originated in single individuals, but must have been created in that numeric harmony which is characteristic in each species."

CHAPTER XI.

HYBRIDITY.

DIFFERENT SPECIES OF ANIMALS FERTILE IN VARIOUS DEGREES.SOME HYBRIDS FERTILE TO AN UNLIMITED DEGREE. THE NEARER SPECIES APPROXIMATE, THE MORE PROLIFIC THE PROGENY.

THE

HE fact that the different races of mankind unite and produce offspring, and that their children are fertile among themselves, is still regarded by some monogenists as the stronghold of their theory. But the investigations of late years prove this to be a very unreliable support. The argument is, that the offspring of different species, like the mule, is absolutely infertile; but inasmuch as the offspring of different races of men are prolific, therefore they must belong to one species. The progeny of the Caucasian and the negro is fertile, and, therefore, the white man and the negro belong to the same species.

The law of hybridity seems to be most capricious, for it is proved, in innumerable cases, that different species of both animals and plants are fertile in various degrees. In the Encyclopædia Britannica, article "Hybridism," we read: "As a general rule, animals or plants belonging to distinct species are not able, when crossed with each other, to produce off

spring. There are, however, innumerable exceptions to this rule." Some hybrids are absolutely sterile; others are fertile for a few generations, and others are fertile to an unlimited degree. Some, like the mule, which is considered absolutely infertile, are sometimes capable of fecundation. The dog, which is not, as some suppose, derived from the wolf, produces with the wolf a hybrid which is fertile for three generations. The hybrid of the dog and jackal is fertile for four generations. M. Quatrefages, one of the latest monogenist writers, says that "the hybrid progeny of two moths showed themselves to be fertile inter se for eight generations." The hybrids from the common and Chinese geese, which Mr. Darwin says are species so different that they have sometimes been ranked in distinct genera, are perfectly fertile. The bison, or American buffalo, crossed with the common domestic cattle, produces fertile offspring; the domesticated or "straightbacked" cattle of Europe and America are completely fertile when crossed with the "humped cattle of Asia and Africa, which are generally conceded to be a different species. Other fertile crosses are those of the hare and rabbit, the goat and steinbok, goat and sheep, fox and dog, mallard and muscovy ducks. As a general rule, the nearer species approximate, the more prolific the progeny. Another rule is, that when hybrids are prolific for several generations, the tendency is to infertility and decay.