There are religious interdictions whose object is to separate two sacred things of different species from each other. For example, it will be remembered that among the Wakelbura the scaffold upon which the corpse is exposed must be made exclusively of materials belonging to the phratry of the dead man; this is as much as to say that all contact between the corpse, which is sacred, and the things of the other phratry, which are also sacred, but differently, is forbidden. Elsewhere, the arms which one uses to hunt an animal with cannot be made out of a kind of wood that is classed in the same social group as the animal itself.[1004] But the most important of these interdictions are the ones which we shall study in the next chapter; they are intended to prevent all communication between the purely sacred and the impurely sacred, between the sacredly auspicious and the sacredly inauspicious. All these interdictions have one common characteristic; they come, not from the fact that some things are sacred while others are not, but from the fact that there are inequalities and incompatibilities between sacred things. So they do not touch what is essential in the idea of sacredness. The observance of these prohibitions can give place only to isolated rites which are particular and almost exceptional; but it could not make a real cult, for before all, a cult is made by regular relations between the profane and the sacred as such. But there is another system of religious interdictions which is much more extended and important; this is the one which separates, not different species of sacred things, but all that is sacred from all that is profane. So it is derived immediately from the notion of sacredness itself, and it limits itself to expressing and realizing this. Thus it furnishes the material for a veritable cult, and even of a cult which is at the basis of all the others; for the attitude which it prescribes is one from which the worshipper must never depart in all his relations with the sacred. It is what we call the negative cult. We may say that its interdicts are the religious interdicts _par excellence_.[1005] It is only these that we shall discuss in the following pages. But they take multiple forms. Here are the principal ones which we observe in Australia.