I do not, however, wish to attack Mr. Prichard upon all points. There is one of his conclusions which I readily adopt, viz.: "_that the difference of climate occasions very little, if any, important diversity as to the periods of life and the physical changes to which the human constitution is subject_."[148] This conclusion is very well founded, and I shall not seek to invalidate it; but it appears to me that it contradicts a little the principles so ably advocated by the learned physiologist and antiquary. The reader must have perceived that the discussion turns solely upon permanency of type. If it can be proved that the different branches of the human family are each possessed of a certain individuality which is independent of climate and the lapse of ages, and can be effaced only by intermixture, the question of origin is reduced to little importance; for, in that case, the different types are no less completely and irrevocably separated than if their specific differences arose from diversity of origin. That such is the case, we have already proved by the testimony of Egyptian sculptures with regard to the Arabs, and by our observations upon the Jews and gypsies. Should any further proofs be needed, we would mention that the paintings in the temples and subterraneous buildings of the Nile valley as indubitably attest the permanence of the negro type. There we see the same crisped hair, prognathous skull, and thick lips. The recent discovery of the bas-reliefs of Khorsabad[149] has removed beyond doubt the conclusions previously formed from the figured monuments of Persepolis, viz.: that the present Assyrian nations are physiologically identical with those who formerly inhabited the same regions. If similar investigations could be made upon a greater number of existing races, the results would be the same. We have established the fact of permanence of types in all cases where investigation is possible, and the burden of proof, therefore, falls upon the dissenting party.