The mystic virtues attributed to stones as well as to engraved gems during the Middle Ages has been frequently alluded to. Among the different stones (like the sapphire, for instance, the very word for which implies protection against drunkenness) carried in the bezel of the ring, which were supposed to make the wearer proof against evil influences, the most valued was the toadstone (Pl. XXIII, 9). It was supposed to be found in the head of a toad, but is in reality the fossil palatal tooth of a species of fish--the ray. A toadstone--also known as crapaudine and batrachites--in a ring was said to indicate the presence of poison by perspiring and changing colour. Toadstones were much sought after, and were highly prized, even in Shakespeare's day. Sweet are the uses of adversity; Which, like the toad, ugly and venomous, Wears yet a precious jewel in his head. (_As you like it_, II, 1.) Ben Jonson alludes to the custom of wearing the stone in rings:-- Were you enamour'd on his copper rings, His saffron jewel, with the toad-stone in't? (_Volpone_, II, 5.) In addition to the stones already mentioned, greatly valued was the Turkey-stone or turquoise, as the "Compassionate turcoyse, which doth tell, By looking pale, the wearer is not well." (Donne, _Anatomie of the World_.) It was his turquoise ring which Shylock would not have lost "for a wilderness of monkeys." The use of charm rings seems to have been not uncommon in early times. It was one of the articles of impeachment against Hubert de Burgh, the great justiciar of Henry III, that whereas the King had in his treasury a ring which rendered the wearer invincible in battle, his minister furtively removed the same and bestowed it upon Llewellyn of Wales. As charm rings, too, must be reckoned those which enclosed small relics. But rings so used seem for the most part to have been worn attached by a ribbon or chain to the neck, and not on the finger. Since such highly valued objects as charmed stones could only be obtained by a few, cabalistic inscriptions often took their place. Many of the devotional rings with the names Jesus, Mary, and Joseph engraved on them, were used as a preservative against the plague; but the most popular inscription was, as has been seen, the names of the Three Kings of the East, which were a powerful charm against peril by travel and sudden death. Such rings were worn against the cramp. There were also caract rings of superstitious use, which bore charms in the form of inscriptions, such as ANANIZAPTA. Many other rings of this class have cabalistic names and strange barbaric words and combinations utterly unintelligible.