Now, considering the primitive character and remarkable similarity of the fire-festivals observed by all the branches of the Aryan race in Europe, we may infer that these festivals form part of the common stock of religious observances which the various peoples carried with them in their wanderings from their original home. But, if I am right, an essential feature of those primitive fire-festivals was the burning of a man who represented the tree-spirit. In view, then, of the place occupied by the oak in the religion of the Aryans, the presumption is that the tree so represented at the fire-festivals must originally have been the oak. So far as the Celts and Slavs are concerned, this conclusion will perhaps hardly be contested. But both for them and for the Germans it is confirmed by a remarkable piece of religious conservatism. The most primitive method known to man of producing fire is by rubbing two pieces of wood against each other till they ignite; and we have seen that this method is still used in Europe for kindling sacred fires such as the need-fire, and that most probably it was formerly resorted to at all the fire-festivals under discussion. Now it is sometimes prescribed that the need-fire, or other sacred fire, must be made by the friction of a particular kind of wood; and wherever the kind of wood is prescribed, whether among Celts, Germans, or Slavs, that wood is always the oak. Thus we have seen that amongst the Slavs of Masuren the new fire for the village is made on Midsummer Day by causing a wheel to revolve rapidly round an axle of oak till the axle takes fire.(790) When the perpetual fire which the ancient Slavs used to maintain chanced to go out, it was rekindled by the friction of a piece of oak-wood, which had been previously heated by being struck with a gray (not a red) stone.(791) In Germany the need-fire was regularly kindled by the friction of oak-wood;(792) and in the Highlands of Scotland, both the Beltane and the need-fires were lighted by similar means.(793) Now, if the sacred fire was regularly kindled by the friction of oak-wood, we may infer that originally the fire was also fed with the same material. In point of fact, the perpetual fire which burned under the sacred oak at the great Slavonian sanctuary of Romove was fed with oak-wood;(794) and that oak-wood was formerly the fuel burned in the midsummer fires may perhaps be inferred from the circumstance that in many mountain districts of Germany peasants are still in the habit of making up their cottage fire on Midsummer Day with a heavy block of oak-wood. The block is so arranged that it smoulders slowly and is not finally reduced to charcoal till the expiry of a year. Then upon next Midsummer Day the charred embers of the old log are removed to make room for the new one, and are mixed with the seed-corn or scattered about the garden. This is believed to promote the growth of the crops and to preserve them from blight and vermin.(795) It