Gamboge, Or Camboge, a gum resin of Siam and Cochin China, and produced also in Ceylon. The tree from which it is obtained is the hebradendron cambogioides of Dr. Graham of Edinburgh. The gum was first carried to Europe by the Dutch in 1003. It is imported into the United States only from Canton and Calcutta. The manner of collecting it in Siam is to catch in leaves or cocoanut shells the vel-low milky juice which exudes from the fractured shoots and leaves of the tree, and, transferring this to earthen vessels, leave it to thicken. It is poured when semi-fluid into the hollow joints of the bamboo, and thus receives the cylindrical form and the shape of pipes or hollow cylinders by contraction in solidifying. It is also made into lumps or cakes of several pounds weight; these are commonly more or less mixed with bits of wood and other impurities. Farinaceous matters are also employed to adulterate it, their presence being detected by the green color communicated to the decoction by adding iodine. The inferior kinds are known in commerce as coarse gamboge. Those of finer quality are brittle, with conchoidal fracture, of reddish orange color in the mass, but bright yellow in powder, or when rubbed with water.

It is without odor, and its taste, very slight at first, is soon followed by an acrid sensation in the throat. Its emulsion with much water affords films, which are good microscopic objects for the observation of active molecules. It is wholly taken up by alkaline solutions and by strong acids. Its resinous portion is dissolved by sulphuric ether; the whole by the successive action of ether and water. Dr. Christison gives the following analyses of the different qualities of gamboge:

Gamboge Tree (Hebradendron cambogioides).

The resinous portion is obtained by evaporating the ethereal tincture. It has a deep orange color, and gives a yellow tint to 10,000 times its weight of alcohol. It is entirely insoluble in water. Johnston named it gaImbogic acid, and gave its composition C40H22O9This is said to be an active purgative in the dose of 5 grains, without the drastic and nauseating character of the gum resin. Gamboge is employed as a water color, and also as a medicine. In large doses it is an acrid poison, a single drachm having produced death. It is best used in combination with other and milder cathartics, and is then found an excellent remedy for obstinate constipation. It is also employed in the treatment of apoplexy and dropsy. It is so rarely used except in combinations that its medicinal action is practically confined to these combinations.