GUTTA PERCHA 343 Saline des Vaterlands (Frankfort, 1817); Hand- buch der Geographiefur Lehrer (Leipsic, 1810) ; and Methodik der Geographic (1835). GUTTA PERCHA (Malay, gutta, gum, and per- cha, the name of a tree), an inspissated juice called gutta taban by the Malays, the name be- ing misapplied by the English. The tree which produces the gum was referred by Sir W. J. Hooker in 1847 to the natural order sapotacece and Dr. Wight's new genus iaonandra, and named the isonandra gutta. It was formerly abundant in the forests along the foot of the hills in the Malayan peninsula, but the natives by cutting down the trees to procure the juice exterminated the plant, and the supply now comes from Borneo and other islands of the In- dian archipelago. It is a large tree, commonly 3 to 4, but sometimes 6 ft. in diameter, with a straight trunk and reaching the height of 60 or 70 ft. The branches are numerous and ascend- and crowded with leaves at their extremi- Gutta Percha (Isonandra gutta). ties; these are petiolate, oblong, 4 or 5 in. long and 2 wide, of bright green above and brown- ish beneath. The flowers are small and white. The wood is peculiarly soft, fibrous, and spongy, pale colored, and traversed by longitudinal re- ceptacles filled with the gum, forming ebony- black lines. To the Malays the valuable prop- erties of the juice of the tree were known long before the Europeans became acquainted with the article. The natives found that the gum would become soft and plastic in fcot water, and, being then moulded into any form, would retain this when cold. They made it into ba- sins, vases, shoes, elastic sticks, whips, handles for parangs or axes, &c. The attention of Europeans was first called to it in 1842 by Dr. William Montgomerie, assistant surgeon to the residency at Singapore; and in 1843 Dr. D' Almeida of the same place brought specimens of the gum to England and laid them before the royal Asiatic society. They attracted little attention till further communications from Dr. Montgomerie established the importance of the article by showing its applicability to the same uses as caoutchouc, and to others besides, and also the low cost at which the material could be procured in the greatest abundance. In 1844 a shipment of 2 cwt. was made from Singapore as an experiment, and soon after the product suddenly became a commercial article of importance. In 1847 Dr. Oxley published an interesting account of the tree and its product in a Singapore journal, de- scribing the uses to which he had applied the gum for surgical instruments. He stated that the large trees which were formerly very abun- dant on the island of Singapore had been near- ly all cut down by the natives, who adopted this destructive method of obtaining the juice, and who had sacrificed by his estimation 69,- 180 trees to procure one tenth this number of piculs, which was the exportation from Jan. 1, 1845, to July, 1847. The custom of tapping has since been introduced. The sap soon co- agulates after it is collected, or it is made to do so by boiling, and is then kneaded by hand into oblong masses, 7 to 12 in. long and 4 or 5 broad. Its dark reddish brown color is de- rived from the impurities, as bits of the bark, that have accidentally fallen into the juice, or from sawdust and other substances introduced as adulterants. Purified gutta percha has a brownish red color and a density of 0*979. It is a non-conductor of electricity, and by friction with almost any other substance (gun cotton and collodion are exceptions) it develops nega- tive electricity. At ordinary temperatures it has considerable tenacity, being nearly as strong as leather, but much less flexible. When heated to 115 F. it becomes pasty, and between this and 140 or 150 it may be moulded into vari : ous shapes or drawn out into wires or tubes. It is insoluble in water, and slightly soluble in anhydrous alcohol and anhydrous ether, but soluble in boiling olive oil, from which it is de- posited on cooling. Benzine, sulphide of car- bon, chloroform, and oil of turpentine dissolve it with the aid of heat. It is insoluble in alka- line solutions or hydrochloric and hydrofluoric acids, and therefore may be advantageously used as a material for vessels to contain these liquids. Strong sulphuric acid carbonizes it, and nitric acid oxidizes it, converting it to a yellow resin. Gutta percha is remarkably po- rous. If a thin film be deposited upon a plate of glass or porcelain from its solution in sul- phide of carbqn, when examined with the mi- croscope it will be found full of minute pores. When subjected to traction it becomes fibrous, and will then resist a much greater force with- out extension. Pure gutta percha is a hydro- carbon, having the formula C 20 H 3 2. When ex- posed to light and air it slowly absorbs oxygen, and is converted into a white resin, having the composition C 2 oH 3 2O 2 , and a yellow, C 2 oH 32 0, both of which are soluble in boiling alcohol. The purified commercial article usually con-
