These trees and rocks are not situated at any point in the tribal territory, but, for the most part, they are grouped around the sanctuaries, called ertnatulunga by Spencer and Gillen and arknanaua by Strehlow, where the churinga of the clan is kept.[886] We know the respect with which these localities are enhaloed from the mere fact that the most precious instruments of the cult are there. Each of these spreads sanctity all about it. It is for this reason that the neighbouring trees and rocks appear sacred, that it is forbidden to destroy or harm them, and that all violence used against them is a sacrilege. This sacred character is really due to a simple phenomenon of psychic contagiousness; but in order to explain it, the native must admit that these different objects have relations with the different beings in whom he sees the source of all religious power, that is to say, with the ancestors of the Alcheringa. Hence comes the system of myths of which we have spoken. They imagined that each ertnatulunga marked the spot where a group of ancestors entered into the ground. The mounds or trees which covered the ground were believed to represent their bodies. But as the soul retains, in a general way, a sort of affinity for the body in which it dwelt, they were naturally led to believe that these ancestral souls continued to frequent these places where their material envelope remained. So they were located in the rocks, the trees or the water-holes. Thus each of them, though remaining attached to some determined individual, became transformed into a sort of _genius loci_ and fulfilled its functions.[887] The conceptions thus elucidated enable us to understand a form of totemism which we have left unexplained up to the present: this is individual totemism. An individual totem is defined, in its essence, by the two following characteristics: (1) it is a being in an animal or vegetable form whose function is to protect an individual; (2) the fate of this individual and that of his patron are closely united: all that touches the latter is sympathetically communicated to the former. Now the ancestral spirits of which we have just been speaking answer to this same definition. They also belong, at least in part, to the animal or vegetable kingdoms. They, too, are protecting geniuses. Finally, a sympathetic bond unites each individual to his protecting ancestor. In fact, the nanja-tree, representing the mystical body of this ancestor, cannot be destroyed without the man's feeling himself menaced. It is true that this belief is losing its force to-day, but Spencer and Gillen have observed it, and in any case, they are of the opinion that formerly it was quite general.[888] The identity of these two conceptions is found even in their details.