Page:Popular Science Monthly Volume 1.djvu/81

Rh When, on the contrary, individuals which are only of different races, but of the same species, are brought together, that is to say, when we produce a mongrel, is the result the same? No, it is exactly contrary.

These crossings are always fertile, and sometimes more so than the union of animals of the same race. But especially the children and grandchildren are also as fertile as the parents and grandparents; so much so that they propagate their kind indefinitely. The difficulty here is not to procure mixed races: the difficulty is, when we have pure races that we desire to preserve, to keep strange blood from modifying them.

Races thrive by crossing that is, by the union of different races of the same species, they multiply abundantly around us; such are our street dogs, our roof cats, our coach horses, all our animals where the race is indistinct; because of crossbreeding in all directions, the differential characters becoming confounded.

So far from experiencing difficulty in obtaining offspring from races, the men who are occupied with cattle, with sheep, with horses, amateurs in dogs, in pigeons, know with what watchful care they must protect their favorite race.

Here, then, is a general fact, and from this fact it results that fertility is the law of union between animals belonging to different races.

Here, gentlemen, you see the great distinction, the fundamental distinction, between species and race. And, it is all the more important to recognize and record this distinction, as it facilitates experiment. When you have two different vegetables, or two different animals, and wish to know whether they belong to two distinct species, or only to two races of the same species, marry them. If the union proves immediately fertile, if the fertility is propagated and persists, you may affirm that, notwithstanding the differences which separate them, these vegetables and these animals are only races of the same species. If, on the contrary, you see the fertility disappear completely or diminish notably at the first union, if you see it decreasing, and go on diminishing, to disappear at the end of a few generations, you may without hesitation affirm that these vegetables and these animals belong to distinct species.

Gentlemen, I have discoursed at length of vegetables and animals, of the coffee tree, of the turkey, of the rabbit, of the dog, of the cat, of cattle, etc., and you may think that I am forgetting man. On the contrary, I have not ceased to think of him.

What is our question concerning man? Distinctly this.

Look once more at these designs. They show you differences, marked enough, between the human groups, although less considerable than at first appears.

Now, we do not know the type or the primitive types of these human groups.