This impossibility of one race being transformed into another is often brought forward as an objection against Monogenism. It is nevertheless the natural consequence of the phenomena, of which I have endeavoured to give a short account, and is easily explained. Every race is a _resultant_ whose _components_ are, partly the species itself, partly the sum of the modifying agents which have produced the deviation from the type. We cannot separate those two elements, and races which have run wild show us to what extent the fusion can go. Every race which is fixed, when brought under the conditions of life which have formed another, will doubtless approximate to the latter; but it will partly retain its former impress, as the fruit-trees of Van Mons and the wild dogs of Martin de Moussy have done. Such is what would take place even among primary races directly detached from the primitive type, and which have only been subject to the action of one fixed condition of life. But with the Negro and the White, the question is much more complex. These two extreme types represent the last product of two series of long-continued actions, whose diversity and multiplicity are indicated by the geographical stations themselves. Europe and tropical Africa have given them, if the expression may be used, the _last touches_; but their outline was _sketched out_ long before they reached their present habitat. By their transposition, we only submit each of them to a part of the influences which have formed the other, and consequently a complete exchange of characters could never take place. XIII. Without denying absolutely the influence of the conditions of life upon man, most polygenists refuse to admit that they have the power of producing new races. To support their statements, they appeal to the persistence of certain types for a considerable lapse of time, and insist most strongly upon certain facts derived from Egypt. On this latter point I readily agree with them. It is quite true that pictures and Egyptian sculptures point to the existence in the valley of the Nile of a type, or rather types, which are remarkably uniform; and whoever has visited these countries has certainly been struck, as I was, with the great resemblance of the peoples of the present to those of the past. But what reasons are there why the inhabitants of the valley of the Nile should change? What cause, except intercrossing, could determine any modification in their physical characters? In this region, which is exceptional in so many respects, nothing has changed since historic times, neither the earth, the sky, nor the river; habits, customs, and daily life have remained as they were in the time of the Pharaohs; the Egyptian even uses implements in our days, which are exactly like those which were used fifty or sixty centuries ago by his ancestors.