Again, in speaking of the genus vulpes (foxes), the same work says:—
"The characters of this genus differ so slightly from those of the genus canis, that we are induced to pause before removing it from the sub-genus in which it had so long remained. As a general rule, we are obliged to admit that a large fox is a wolf, and a small wolf may be termed a fox. So inconveniently large, however, is the list of species in the old genus canis, that it is, we think, advisable to separate into distinct groups such species as possess any characters different from true wolves."
Speaking of the origin of the domestic dog, Dr. Bachman, in his work on Unity of Races, p. 63, says:—
"Notwithstanding all these difficulties—and we confess we are not free from some doubts in regard to their identity (dog and wolf)—if we were called upon to decide on any wild species as the progenitor of our dogs, we would sooner fix upon the large wolf than on any other dog, hyena, or jackal," &c.
The doctor is unable, here at least (and we can point out many other cases), to "designate species;" and the recent investigations of Flourens, at the Jardin des Plantes, prove him wrong as regards the origin of the dog. The dog is not derived from the "large wolf," but, with it, produces hybrids, sterile after the third generation. The dog forms a genus apart.
We repeat, then, that in a large number of genera, the species cannot be separated by any anatomical characters, and that it is from their history alone naturalists have arrived at those minute divisions now generally received. We may, without the fear of contradiction, go a step further, and assert that several of the races of men are as widely separated in physical organization, physiological and psychological characters, as are the canidæ, equidæ, felines, elephants, bears and others. When the white races of Europe, the Mongols of Asia, the aborigines of America, the black races of Africa and Oceanica are placed beside each other, they are marked by stronger differences than are the species of the genera above named. It has been objected that these gaps are filled by intermediate links which make the chain complete from one extremity to the other. The admission of the fact does not invalidate our position, for we have shown elsewhere (see Types of Mankind) gradation is the law of nature. The extreme types, we have proven, have been distinct for more than 5000 years, and no existing causes during that time have transformed one type into another. The well-marked negro type, for example, stands face to face with the white type on the monuments of Egypt; and they differ more from each other than the dog and wolf, ass and Equis Hemionus, lion and tiger, &c. The hair and skin, the size and shape of head, the pelvis, the extremities, and other points, separate certain African and Oceanican negroes more widely than the above species. This will not be questioned, whatever difference of opinion may exist with regard to the permanency of these forms. In the language of Prof. Leidy, "the question to be determined is, whether the differences in the races of men are as permanent and of as much value as those which characterize species in the lower genera of animals." These races of men too are governed by the same laws of geographical distribution, as the species of the lower genera; they are found, as far back as history can trace them, as widely separated as possible, and surrounded by local Floræ and Faunæ.
VARIETIES.
This term is very conveniently introduced to explain all the difficulties which embarrass this discussion. Dr. Bachman insists that all the races of men are mere varieties, and sustains the opinion by a repetition of those analogies which have been so often drawn from the animal kingdom by Prichard and his school. It is well known that those animals which have been domesticated undergo, in a few generations, very remarkable changes in color, form, size, habits, &c. For example, all the hogs, black, white, brown, gray, spotted, &c., now found scattered over the earth, have, it is said, their parentage in one pair of wild hogs. "This being admitted," says Dr. B. "we invite the advocates of plurality in the human species to show wherein these varieties are less striking than their eight (alluding to Agassiz) originally created nations." Again—
"And how has the discovery been made that all the permanent races are mere varieties, and not 'originally created' species, or 'primitive varieties?' Simply because the naturalists of Germany, finding that the original wild hog still exists in their forests, have, in a thousand instances, reclaimed them from the woods. By this means they have discovered that their descendants, after a few generations, lose their ferocity, assume all colors," &c.