CROTON, is the name of a plant which is largely used in medicine. Cascarilla bark is yielded by the Croton cascarilla, a tree or shrub growing in the vicinity of Jalapa. It occurs in pieces about a foot long. The colour ex ternally is yellowish, ash-gray, or varying to reddish brown : this last colour is mostly owing to the presence of lichens. The inner surface is a dirty or rusty brown colour. The odour is faintly aromatic : taste bitter, not un pleasant, and stimulating. One pound of bark yields one drachm and a half of volatile oil. This bark is sometimes mixed with cin chona barks, being called Gray Fever Bark. Cretan tiglium, an inhabitant of the Moluccas, Ceylon, and other parts of the East Indies, is a powerful drug ; every part, wood, leaves, and fruit, seems to participate equally in the energy. The Molucca grains, formerly used in medicine, were the seeds of this species.
Croton lacciferum is a native of the East Indies. This species is said to furnish the finest of all the sorts of lac, but scarcely ever to find its way to England ; it is very pure, of a bright red, and furnishes a brilliant varnish in Ceylon. From the Croton balsamifcrum, the liqueur called Bait de Mantes is distilled. CRUCIBLE, is a chemical vessel in which substances are exposed to high temperatures.
Earthen crucibles are used in assaying ores : for these purposes the refractory kind, called Hessian or Cornish crucibles, are prepared. Black lead crucibles, formed of about three parts of plumbago and one of good clay, are much employed, especially in melting metals. Glass-makers' crucibles are usually made of Stourbridge clay. Crucibles of silver and of platinum are employed in various chemical processes.