The conclusion suggested by these examples is very strongly corroborated by an examination of our own race. We need not enter into the subtleties of sub-racial classifications for the present purpose, but will simply regard the European race in relation to European culture generally. It is clear that all those startling technological advantages that most sharply divide us from other peoples are a mushroom growth little over a century old. In the first half of the nineteenth century matches were unknown and the processes of fire-making were not superior to those of many primitive tribes. The steam-engine and the industrial revolution are of very little greater antiquity, not to speak of electrical contrivances and applied chemistry. The difference between ourselves and our forefathers is at first blush so tremendous that _a priori_ it would seem to be explainable only by very great mental differences, yet nothing is more certain than that their innate mentality was exactly the same. The cultural difference becomes more and more glaring as we proceed backwards, say, to the period antedating the art of printing. A portion of our Middle Ages compares rather unfavorably with contemporaneous Arabian or Chinese civilization. “If we go back to the fifteenth century,” says Professor Giles, “we shall find that the standard of civilization, as the term is usually understood, was still much higher in China than in Europe; while Marco Polo, the famous Venetian traveler of the thirteenth century, who actually lived twenty-four years in China, and served as an official under Kublai Khan, has left it on record that the magnificence of Chinese cities, and the splendor of the Chinese court, outrivaled anything he had ever seen or heard of.”[10] Certainly the racial factor, which is a constant, cannot account for the amazing changes in culture which we encounter in passing from one period of our era to another. If we are interested in explaining these cultural phenomena, we must cast about for some other determinants.