GAMBOGE, gam-Woj', or -1)6r, or GAM BOGE (from Camboja, Cambodia, Skt. Kamboja,. where the tree abounds). A gum resin brought from the East Indies, and believed to be the produce chiefly of Garcinia Cambogia, also known as Garcinia cambogioides, a tree of the natural order Guttiferke, a native of Ceylon, Siam, Camboja, etc. The gamboge-tree attains a height of forty feet, has smooth oval leaves, small polygamous flowers, and clustered succulent fruit. When the bark of a tree is wounded, gam boge exudes as a thick, viscid, yellow juice, which hardens by exposure to the air. The finest gam boge comes from Siam. American gamboge, which is very similar, and used for the same purposes, is obtained from Vismia Guianensis (natural order Hypericineme), a native of Mexico and Suri nam. Gamboge occurs in commerce in three forms: (1) In rolls or solid cylinders; (2) in pipes or hollow cylinders; and (3) in cakes or amorphous masses. The first two kinds are the
purest. Good gamboge contains about 70 per cent. of resin and 20 per cent. of gum, the re mainder being made up of woody fibre, fecula, and moisture. The resin of gamboge, known as gambogic acid, is a bright yellow substance soluble in alcohol and in ether. Its composition is represented by the formula It is much used by painters to produce a beautiful yellow color. It is also employed for staining wood, and for making a gold-colored lacquer for brass. It has a Shelly fracture, is destitute of smell, and has an acrid taste. If taken internally, it acts as a cathartic, producing a large amount of secre tion. It is but rarely used in medicine, and never alone, as it causes griping and irritation of the alimentary canal. See MANGOSTEEN.