More emphatically still is this conception of a reciprocity of benefits expressed in another consecrated action, that of Sacrifice. Sacrifice holds a most important place in all religions. It originates in a stage of the human mind which, if not quite as primitive as that which gives rise to prayer, is nevertheless so early as to be practicably inseparable from it. Wherever we find prayer, we find sacrifice; but as the latter is generally found organized under definite forms, and confined to certain specified objects, we may conclude that in the state in which we recognize it, it implies a certain degree of regulation and forethought on the part of religious authorities which we do not meet with in the simplest types of prayer. Prayer is often the mere natural outpouring of our wants before a power which is considered capable of fulfilling them: sacrifice, though doubtless in the first instance an equally artless offering of gifts to beings who are regarded with veneration and gratitude, is soon converted into a formal presentation of acknowledged dues, performed under ecclesiastical supervision. No doubt prayer also tends to assume this formal character; but we have hitherto considered it in its uncorrupted aspect; its treatment in its later developments belongs to another portion of this chapter. The idea which presides over sacrifice is obvious. The sacrificer argues that if he can make acceptable presents to the gods, they will smile upon him and be disposed to promote his ends; whereas if he keeps the whole of his possessions for worldly purposes, they will regard him with indignation, and refuse him their assistance when he may happen to stand in need of it. There is also involved in sacrifice a sense of gratitude: the gods having given us the fruits of the earth, behooves us to make some acknowledgment of their bounty.