In the dark ages the blood of little children had a wide-spread reputation for its medicinal virtue. The idea that diseased and withered humanity, having failed to discover the fountain of eternal youth, might find a new well-spring of life in bathing in, or being sprinkled with, the pure blood of a child or a virgin, had long a firm hold upon the minds of the people. Hartmann von Aue's story, _Der arme Heinrich_, and a score of similar tales testify of the folk-faith in the regeneration born of this horrible baptism--a survival or recrudescence of the crassest form of the doctrine that the life dwells in the blood. Strack, in his valuable treatise on "Human Blood, in Superstition and Ceremonial," devotes a brief section to the belief in the cure of leprosy by means of human blood (361. 20-24). The Targumic gloss on Exodus ii. 23--the paraphrase known as the Pseudo-Jonathan--explains "that the king of Egypt, suffering from leprosy, ordered the first-born of the children of Israel to be slain that he might bathe in their blood," and the Midrasch Schemoth Rabba accounts for the lamentation of the people of Israel at this time, from the fact that the Egyptian magicians had told the king that there was no cure for this loathsome disease, unless every evening and every morning one hundred and fifty Jewish children were slain and the monarch bathed twice daily in their blood. Pliny tells us that the Egyptians warmed with human blood the seats in their baths as a remedy against the dreaded leprosy. According to the early chroniclers, Constantine the Great, on account of his persecution of the Christians, was afflicted with leprosy, which would yield neither to the skill of native nor to that of foreign physicians. Finally, the priests of Jupiter Capitolinus recommended a bath in the blood of children. The children were gathered together, but "the lamentations of their mothers so affected the Emperor, that he declared his intention of suffering the foul disease, rather than be the cause of so much woe and misery." Afterwards he was directed in a dream to Pope Sylvester, was converted, baptized into the Church, and restored to health (361. 22). Other instances of this fearful custom are mentioned in the stories of Percival (in the history of the Holy Grail), of Giglan de Galles et Geoffrey de Mayence, and the wide-spread tale of Amicus and Amelius and its variants, Louis and Alexander, Engelhard and Engeltrut, Oliver and Arthur, etc., in all of which one of the friends is afflicted with leprosy, but is cured through the devotion of the other, who sacrifices his own children in order to obtain the blood by which alone his friend can be restored to health. Usually, we are told, God rewards his fidelity and the children are restored to life.