He discovered wonderful stories, also, about jewels. In Alphonso's Clericalis Disciplina a serpent was mentioned with eyes of real jacinth, and in the romantic history of Alexander, the Conqueror of Emathia was said to have found in the vale of Jordan snakes 'with collars of real emeralds growing on their backs.' There was a gem in the brain of the dragon, Philostratus told us, and 'by the exhibition of golden letters and a scarlet robe' the monster could be thrown into a magical sleep and slain. According to the great alchemist, Pierre de Boniface, the diamond rendered a man invisible, and the agate of India made him eloquent. The cornelian appeased anger, and the hyacinth provoked sleep, and the amethyst drove away the fumes of wine. The garnet cast out demons, and the hydropicus deprived the moon of her color. The selenite waxed and waned with the moon, and the meloceus, that discovers thieves, could be affected only by the blood of kids. Leonardus Camillus had seen a white stone taken from the brain of a newly killed toad, that was a certain antidote against poison. The bezoar, that was found in the heart of the Arabian deer, was a charm that could cure the plague. In the nests of Arabian birds was the aspirates, that, according to Democritus, kept the wearer from any danger by fire.