ISONANDRA GUTTA. Hook.
Didropsis gotta, Benth. I Gutta-percha tree, . ENG.
Mazer wood tree, . ENG. Taban, Niato, . MALAY.
The gutta-percha tree is a native of the Malay Archipelago, Sumatra, and Borneo. In 1842 the discovery was made that its gum was suited for an infinite number of applications ; and now there is scarcely any vegetable product more extensively useful, or one more generally sought after for mercantile purposes. Dr. Montgomerie observed in the hands of a Malay woodsman at Singapore, the handle of a parang, made of a substance quite new to him, and which he found could be moulded into any form, by simply dipping it in boiling water until it was heated throughout, when it became plastic as clay, and when cold regained, unchanged, its original hardness and rigidity. Dr. Montgomerie transmitted specimens of this substance to England on the 1st March 1843, and received the gold medal of the Society of Arts for its introduction, as a new and hitherto unknown substance, likely to be useful for various purposes in the arts.' Gutta-percha, in its crude state, differs in many particulars from caoutehouc ; it is of a pale yellowish, or rather dirty white colour ; it is con tained in the sap and milky juice, which quickly coagulates on exposure to the air,—from 20 to 30 lbs. being the average produce of one tree. For collecting the sap, the trees are felled, barked, and left dry and useless. Hence forests are soon cleared of the gotta trees, whereas it is believed that a constant and moderate supply might be secured by incisions in the bark, as in the case of The gutty is received in blocks, or in rolls of thin layers, being, in the first place, freed from impurities by kneading in hot water, when it is left soft, plastic, and of a whitish grey.
When thus prepared, the gutty has many curious properties. Below the temperature of fifty degrees it is as hard as wood, but it will receive an indentation from the finger nail. When softened in hot water, it may easily be cut and moulded, and it will harden, as it cools, to its former rigidity ; and it may be softened and hardened any number of times, without injury to the material. Unlike caontchouc, it has little elasticity, but it has such tenacity, that a slip one eighth of an inch substance sustained 42 lbs. weight; and only broke with a pressure of 56 lbs. When drawn out, it remains without contracting. It has been made subservient to the manufacture of tubings, mouldings for picture-frames, cath eters and other surgical instruments, whips, thongs, cricket balls, driving bands or straps for mechanic purposes,'soles for boots and shoes ; in solution, also, like caoutcbouc, for waterproofing cloth. It is likewise employed in mastics, cements, and is burnt and made into printing ink and paint. —Tomlinson ; Cat. Exhib., 1862.