"If species have a tendency to transformation, to pass one into another, why has not time, which, in everything, effects all that can happen, ended by disclosing, by betraying, by implying this tendency. "But time, they may tell me, is wanting. It is not wanting. It is 2000 years since Aristotle wrote, and we recognize in our day all the animals which he describes; and we recognize them by the characters which he assigns.... Cuvier states that the history of the elephant is more exact in Aristotle than in Buffon. They bring us every day from Egypt, the remains of animals which lived there two or three thousand years ago--the ox, crocodiles, ibis, &c. &c., which are the same as those of the present day. We have under our eyes _human mummies_--the skeleton of that day is identical with that of the Egyptian of our day." (M. Flourens might have added that the mummies of the white and black races show them to have been as distinct then as now, and that the monumental drawings represent the different races more than a thousand years further back.) "Thus, then, through three thousand years, no species has changed. An experiment which continues through three thousand years, is not an experiment to be made--it is an experiment _made_. Species do not change."[208] _Permanence of type_, then, is the only test which he can adduce for the designation of species, and he here comes back plainly to the position we have taken. Let us now test the races of men by this rule. The white Asiatic races, the Jew, the Arab, the Egyptian, the negro, at least, are distinctly figured on the monuments of Egypt and Assyria, as distinct as they are now, and _time_ and change of climate have not transformed any one type into another. In whatever unexplored regions of the earth the earliest voyagers have gone, they have found races equally well marked. These races are all prolific _inter se_, and there is every reason to believe that we here find the fourth and last degree of hybridity. Whether the prolificacy is _unlimited_ between all the races or species of men is still an unsettled point, and experiments have not yet been fully and fairly made to determine the question. The dog and wolf become sterile at the _third_. The dog and jackal at the fourth generation, and who can tell whether the law of hybridity might not show itself in man, after a longer succession of generations. There are no observations yet of this kind in the human family. It is a common belief in our Southern States, that mulattoes are less prolific, and attain a less longevity than the parent stocks. I am convinced of the truth of this remark, when applied to the mulatto from the strictly white and black races, and I am equally convinced, from long personal observation, that the _dark_-skinned European races, as Spaniards, Portuguese, Italians, Basques, &c., mingle much more perfectly with the negroes than do fair