From this passage, and from the reference which we have cited from Euripides’ _Iphigenia Taurica_, as well as from more general considerations we conclude that homicide-purgation normally included the shedding of animal blood when some element of guilt was admitted. It is possible, therefore, that the rite described by Sophocles, in the _Oedipus Coloneus_,[135] was not conceived as a genuine purgation-rite but rather as an exceptional local procedure which was intended to supplement a presumed anterior purgation.[136] That Attica was noteworthy for its scruples regarding ‘pollution’ may be inferred from the remarks of the Corinthian Chorus in the _Medea_ of Euripides.[137] We are entirely on the side of Müller[138] and Philippi[139] in the view that purgation, in historical Greece, was applied to the authors of justifiable bloodshed.[140] This we may regard as a further confirmation of our opinion that homicide-purgation was not a placation of ghosts or an expiation offered to gods, but a solemn and sacred symbol of reconciliation between the slayer and his native gods.[141] Our hypothesis of the origin of the Greek doctrine of homicide as a pollution will receive still further confirmation when we describe in more detail the historical Greek system of penalties for bloodshed and the conceptions of those penalties which are found in Attic tragedy. We will now give the reasons which have led us to associate the Greek ‘pollution’ doctrine with the Delphian Apollo and his Amphictyonic League, after which we shall be in a position to discuss[142] the influence of the ‘pollution’ doctrine on ‘wergeld’ and the legality of ‘private settlement.’ The following account is intended as a supplement to Müller’s analysis, which errs only in attributing purgation-rites exclusively to Apollo and his priests. APOLLO AND POLLUTION