GAMBOGE, or CAMB0GE, a gum-resin, used in medicine and the arts, brought from the East Indies, and believed to be the produce chiefly of Cambogia gotta, also known as hebradendron gambogioides, a tree of the natural order guttiferw, a native of Ceylon, Siam, Cambodia, etc. The gamboge-tree attains a height of 40 ft., has smooth oval leaves, small polygamous flowers, and fruit. The fruit is about 2 in. in diameter, sweet and eatable, and is also much used as an ingredient in sauces. When the bark of the tree is wounded, G. exudes as a thick viscid yellow juice, which hardens by exposure to the air. Another species of the same genus (C. pictoria) occurs in the Mysore; and is believed to produce G. of similar quality. The finest G. comes from Siam. American G., which is very similar, and used for the same purposes, is obtained from vismia Guianensis, a tree of the natural order hypericince, a native of Mexico and Surinam.
G. occurs in commerce in three forms: I. in rolls or solid cylinders; 2. in pipes or hol low cylinders; and 3. in cakes or amorphous masses. The first two•kinds are the purest. Good G. contains about 70 per cent of resin and 20 per cent of gum, the remainder being made up of woody fiber, fecula, and moisture. On to dryness the ethereal texture of the pure gum-resin, we obtain a deep orange-colored or cherry-red substance, 'to which the terms gambogie and gambodic acid have been applied. Its com position is represented by the formula C4011”0,., according to Johnston (Phil. Trans. 1839).
As the detection of G. in quack medicines, etc., is occasionally of great medico legal importance (death having often taken place in consequence of the administration of Morison's pills and similar preparations), we may mention the following simple mode of procedure. Digest one portion of the suspected substance in alcohol, and another in
ether. In each case, if G. is present, we obtain an orange-colored tincture. The ethereal tincture dropped in water yields, on the evaporation of the ether, a thin, bright yellow film of gambogic acid, which is soluble in caustic potash. The alcoholic tinc ture dropped into water yields a bright, opaque, yellow emulsion, which becomes trans parent, and of a deep red color on the addition of caustic potash. On the addition of acetate of lead to either of these solutions, we have a yellow precipitate of gambogiate of lead; similarly, sulphate of copper yields a brown, and the salts of iron a dark-brown precipitate of the respective gambogiates of copper and iron.
In doses of a drachm. or even less, G. acts as an acrid poison, causing extreme vomiting and purging, followed by fainting and death. In small doses of from one to three grains, combined with aloes and ginger or aromatic powder, it may be given in case of obstinate constipation, in cerebral affections (as apoplexy, or where there is an apoplectic tendency), in dropsy (especially if connected with hepatic obstruction), and as a remedy for tape-worm. The use of G. is objectionable when there is an irritable or inflammatory condition of the stomach or intestines, or a tendency to abortion; and it is not very often prescribed by orthodox practitioners.
G., is much used by painters to produce a beautiful yellow color. It is also employed for staining wood, and for making a gold-colored tacker for brass. It has a shelly fracture, is destitute of smell, and has an an acrid taste. It burns with a denso smoke and many sparks.