The facts enumerated above prove that burial was long practised, though it is impossible to say when it first cattle into use. About the time of the beginning of the Bronze age, or perhaps even earlier, however, a remarkable change took place in the ideas of man, and the dead instead of being buried intact were consumed by fire on the funeral pile. What can have been the origin of this custom? What race first practised it? It has long been supposed by many archæologists that it was the Aryans from the lofty Hindoo Koosh Mountains who first introduced into Europe a civilization more advanced than that which had hitherto obtained there, and taught the people to cremate instead of bury their dead. This theory was accepted for a considerable time without question, but of late years a new school, headed by Penka, has arisen who claim that the reformers came not from the East but from the North. The Marquis de Saporta had indeed before suggested that the primitive races who were the contemporaries of the mammoth and the rhinoceros came originally from the polar regions, where the remains of a luxuriant vegetation prove that climatic conditions prevailed in remote times of a very different character to those of the present day. The lignites of Iceland are made up of tulip, plantain, and nut-trees, even the vine sometimes occurring. In the ferruginous sandstones, associated with the carboniferous deposits of Spitzberg, the beech, the poplar, the magnolia, the plum tree, the sequoia, and numerous coniferous trees can be made out. The sturdy sailors who dare the regions of perpetual ice come across masses of fossilized wood in Banks, Grinnell, and Francis Joseph’s Lands, at 88° N. Lat. Among this fossil wood Heer made out the cypress, the silver pine, the poplar, the birch, and some dicotyledons with caducous leaves. These were not relics of wood which had drifted where it was found on floating ice, but of an actual local vegetation, as proved by trunks still erect in their original positions, buds, leaves, and flowers in every stage of growth, fruits in every stage of ripening. The very insects that had lived on honey from the flowers or on the leaves themselves could be identified. In those remote days, life, abundant life, similar to that now only found in the temperate countries farther south, flourished in those polar regions, so long supposed to have never been anything but lifeless deserts. [Illustration: 110.] Peruvian mummies.