In addition to the precious and semi-precious stones already mentioned, other objects, accounted specially efficacious for certain purposes, were worn. The _peres de eagle_, also called _ætites_, supposed to be found in the nest of the eagle, were particularly valuable during childbirth. _Glossopetræ_, the fossilised teeth of certain kinds of shark, which passed as serpents' teeth, were much used, as well as primitive arrowheads. They were hung round the neck of infants in the belief that they assisted dentition and kept off frights. Of great value also was the bezoar stone, which, like glossopetræ, at one time occupied a prominent place in pharmacopoeia. Coral, which has always been popular, is first mentioned in English wills and inventories in the fourteenth century. It was used for rosaries, and, above all, as a charm--a ring of gold or silver being attached to its stalk. The Romans tied little branches of it round their children's necks to ward off the evil eye; and the infant Saviour in many an early Italian picture is represented wearing a piece of coral in a similar manner.[66] [66] A relic of this superstition still exists in the coral baubles hung with bells, with which infants are aided in cutting their teeth. A fear of poison, common for centuries in royal courts, was responsible for the custom of testing meats and drinks by methods founded upon certain ancient and groundless beliefs. In order to neutralise or detect the presence of poison, certain objects were placed in contact with food or were dipped into liquids. The touching-pieces (_tousches_) or proofs (_espreuves_) employed for the purpose, and considered especially efficacious against poison, were toadstones, glossopetræ, serpentine, jasper, agate and particularly the unicorn's horn. What was foisted upon the credulous public as the horn of the fabled animal was in reality the horn or tusk of a fish--the narwhal or sea-unicorn of the northern seas. Being an object of very great value, the horn was only occasionally kept entire, like the one preserved to this day at New College, Oxford. It was more usually cut into pieces and used as "proofs." An angry unicorne in his full career Charge with too swift foot a jeweller That watched him for the treasure of his brow, And ere he could get shelter of a tree, Nail him with his rich antler to the earth.[67] [67] Quoted from Bussy d'Amboise (1607) by Malone, commenting on the passage, "Unicorns may be betray'd with trees" (_Julius Cæsar_, II, i). These and other objects, when worn upon the person, as was generally the practice, were mounted at one end, or surrounded by a claw-like band of silver.