This substance is frequently confounded by the ignorant with india-rubber, from which, however, it is entirely distinct. It is obtained by evaporating the juice of Isonandra gutta, a tall tree which grows only in the Malayan Archipelago. A tree, which probably numbers fifty summers, is cut down, stripped of its bark, and the juice collected in a cocoanut-shell or plantain-leaf; or else rings are cut in the bark, about a foot apart, and the sap collected and boiled down Gutta-percha, as imported from Malacca, contains several impurities, which consist of soluble salts, together with some organic matter, such as fragments of the bark, etc. It is purified by rasping with cold, and washing with warm water. Afterwards it is heated to 230 degrees Fah. to expel the water, which would interfere with its cohesive power; by being heated, it is also reduced to a single mass. Purified gutta-percha has a density of 0-979, and is a very bad conductor of electricity, for which reason it is so much used for insulating supports in electrical machines and coating the wire of electric cables. Gutta-percha is not acted upon either by water, hydrochloric or acetic acids, alkaline solutions, or alcohol. It is soluble in chloroform, benzol, bisulphide of carbon, rectified mineral naphtha, and rectified oil of turpentine.

There are three qualities of gutta-percha imported. The best, native, which occurs in tough flexible pieces, of a light brown or chocolate color, of all sizes and shapes. Inferior native, which is lighter in color, and more easily torn in pieces than the above. The boiled sort, which comes to Europe in oblong pieces: it probably consists of the two native sorts, boiled together to give it a fine appearance.

The solution of gutta-percha has been found very useful as an artificial cuticle in the care of cuts, burns, and extensive abrasions. Mr. Acton, however, after making various experiments with solutions of gun-cotton, caoutchouc, and guttapercha, arrived at the conclusion that a compound solution of caoutchouc with gutta-percha possesses the requisite qualities for preserving the skin against the action of contagious poisons, and also as a covering for the hands duriag post-mortem examinations.

Gutta-percha has been used for belting, and as an insulator for covering wires for electrical purposes. When warmed it is perfectly plastic, and may be readily molded into any form. Indeed, it may be kneaded between the fingers into almost any form; and consequently it has been used for various extemporized articles, such as stoppers for bottles, photographic baths, voltaic battery cells, and an infinite variety of surgical appliances. As it takes an impression of the very finest and most delicate lines and forms it has been formed into beautiful moldings, picture-frames, and other ornamental articles. When cool it is quite stiff and hard, and is quite durable.