Juvenal says that the Scythians drank the blood of their enemies to quench their thirst.
Occasionally a religious ceremony has given sanction to cannibalism.

It is said that in the Island of Chios there was a rite by way of sacrifice to Dionysius in which a man was torn limb from limb, and Faber tells us that the Cretans had an annual festival in which they tore a living bull with their teeth.

Spencer quotes that among the Bacchic orgies of many of the tribes of North America, at the inauguration of one of the Clallum chiefs on the northwest coast of British America, the chief seized a small dog and began to devour it alive, and also bit the shoulders of bystanders.

In speaking of these ceremonies, Boas, quoted by Bourke, says that members of the tribes practicing Hamatsa ceremonies show remarkable scars produced by biting, and at certain festivals ritualistic cannibalism is practiced, it being the duty of the Hamatsa to bite portions of flesh out of the arms, legs, or breast of a man.
Another cause of cannibalism, and the one which deserves discussion here, is genuine perversion or depravity of the appetite for human flesh among civilized persons,--the desire sometimes being so strong as to lead to actual murder.

Several examples of this anomaly are on record.