(M18) The theory that the throwing of stones is practised in certain circumstances as a mode of purification tallies very well with the tradition as to the origin of those cairns which were to be seen by wayside images of Hermes in ancient Greece, and to which every passer-by added a stone. It was said that when Hermes was tried by the gods for the murder of Argus all the gods flung stones at him as a means of freeing themselves from the pollution contracted by bloodshed; the stones thus thrown made a great heap, and the custom of rearing such heaps at wayside images of Hermes continued ever afterwards.(68) Similarly Plato recommended that if any man had murdered his father or mother, his brother or sister, his son or daughter, he should be put to death, and that his body should be cast forth naked at a cross-road outside of the city. There the magistrates should assemble on behalf of the city, each carrying in his hand a stone, which he was to cast at the head of the corpse by way of purifying the city from the pollution it had contracted by the crime. After that the corpse was to be carried away and flung outside the boundaries.(69) In these cases it would seem that the pollution incurred by the vicinity of a murderer is thought to be gathered up in the stones as a material vehicle and to be thrown away with them. A sacrificial custom of the Brahmans, prescribed in one of their sacred books, is susceptible of a like interpretation. At a certain stage of the ritual the sacrificer is directed to put a stone into a water-pot and to throw it away in a south-westerly direction, because that is the region of Nirriti, the goddess of Evil or Destruction. With the stone and the pitcher he is supposed to cast away his pain and evil; and he can transfer the pain to another by saying, as he throws away the stone and the pitcher, “Let thy pain enter him whom we hate,” or “Let thy pain enter so-and-so,” naming his enemy; but in order to ensure the transference of the pain to his enemy he must take care that the stone or the pitcher is broken.(70)