We shall see later that, in the Apolline code, death was probably the invariable penalty for kin-slaying,[118] and there was no ‘purgation’: but in other cases purgation was possible, and in the purgation ceremony an animal was slain. The conclusion which is suggested _prima facie_ by these facts, namely, that at one time human sacrifice was the only purgation for homicide, is not necessarily correct. We believe it is incorrect. We agree with Glotz[119] in deriving the purgation rite from Chthonian sacrifice in its general aspect. In such sacrifice, originally, human beings were probably offered, prior to, contemporarily with, and even subsequent to, the adoption of animal sacrifice. We cannot legitimately assume that the latter supplanted the former. Glotz points out that religion, being conservative, tends to preserve in ritual elements which civilisation has abandoned. Hence arose the mock-rites of human sacrifice which took place in historical times. The belief that homicide-purgation originated in the sacrificial slaying of the murderer was encouraged by the similarity which existed between the rites of homicide-purgation and the ordinary ritual of Chthonian expiation. We shall see later that, in the ceremonial of purification which was applied to persons guilty of homicide, from the seventh century B.C. onwards, the blood of a slain animal was poured over the hands of the slayer, and allowed to flow away into the sea or into a running stream. Thus, homicide-purgation (καθαρμός) easily came to be regarded as a kind of expiation (ἱλασμός); but it differs fundamentally in meaning from expiation, inasmuch as it is symbolical of the fact that a social or religious obligation has been discharged, rather than of the fact that it is being thereby discharged. The sacrifice of an ox or a sheep or a ram to a god or a ghost was _in itself_ a payment or a retribution. But homicide-purgation (καθαρμός) was never permitted _until_ the slayer had re-established his normal social equilibrium, had suffered the penalty prescribed by law, namely exile, temporary or perpetual, and was ready to resume religious communion with his fellow-men. Since, therefore, homicide-purgation was rather a symbol of reconciliation than a medium of expiation, it was more closely allied to the rites which accompanied the swearing of oaths,[120] the giving of pledges and the making of contracts. The animal on which an oath was sworn could not be eaten: so, too, the pig or the lamb by whose blood a murderer was ‘cleansed’ could not be eaten. Now it is unfortunate that such ceremonies, which were really symbolic of reconciliation, should have been so similar to the general ritual of religious expiation that they could easily be confused. There is a vast difference in meaning between reconciliation and the aversion of evil, yet all these ideas were confused in the general system of Chthonian ritual. As an illustration of this confusion we may cite