man, remounting by a certain number of intermediary species, of whose nature it is impossible for us at present to form any idea,--to this primordial vertebrate animal which we admit. This species, a rough outline of what man now is, gave birth, after a considerable time, to many other species, whose parallel and unequal evolution, following what we have said concerning animals, has at the present day as contemporaneous (but not the last) illustration, the different _species_ of men designated by the name of races. So that all humanity would be in relationship, if the expression be allowed us, not in the _serial sense_, as monogenists take it, but in the _collateral sense_, and at a degree which we cannot determine; the prognathous races probably less deviated from the former type, the others more separated from this type, and more perfect. It may be seen, and we are bound to make the remark, that we no more pretend to make man a descendant of the ape, than a white man a descendant of a Negro; but it is not impossible, in our opinion, that species of men, as well as the great apes whose relationship hurts our vanity so much, may remount infinitely far in the past to an unknown single species, whose descendants, submitted to multiplied influences, might be modified in different ways by reason of these different influences. We admit, then, that species is an instant of a constant evolution; that it does not exist by itself; and that it is only an appreciation of our senses, localised by time. In our opinion, if species is fixed, it is fixed after the manner of the sun. That is to say, that we cannot perceive any movement in it beyond the merest trifle. It requires thousands of years to discover either solar displacement or specific alteration. This is what makes the determination of species so difficult; some of which may be considered as in progress of formation in reference to others. The difficulty is the same with mankind as it is with animals. We would not dare to contradict, for instance, the opinions of those who see in the Hindú, German, and Celtic population three species in course of formation, all three being probably derived from a species anterior to that which history endeavours at the present day to name; that Aryan race of which such a noble picture is made, and which we believe to be primitive because it is in the horizon of history, just as the ancients saw in the ocean the limits of the world. In a short time, perhaps, some discovery in a poor Asiatic field will take away from the Aryas the characteristic nobility and intelligence which we give to them with so much satisfaction. It belongs to human palæontology alone to enlighten us upon the origin of the _present_ human types; it alone can lead us in a sure path towards the great problem of their origin.