GUT'TA-PER'CHA (Malay gatah, gum + percha, name of a tree). A substance in many respects similar to caoutchouc, and consisting of the dried milky juice of certain trees and climb ers, the best being obtained from the Isonandra gutta, which is found in the peninsula of Malacca and the Malayan Archipelago. The tree belongs to the natural order Sapotacen. It is a very large tree, the trunk being sometimes three feet in diameter, although it is of little use as a timber-tree, the wood being spongy. The leaves are alternate, on long stalks, obovate-oblong, en tire, somewhat leathery, green above, and of a golden color beneath. The flowers are in little tufts in the arils of the leaves, small, each on a distinct stalk, the corolla having a short tube and six elliptical segments; they have twelve stamens and one pistil. Other trees producing good gutta are found in Cochin-China, Venezuela, Costa Rica, and Australia. In 1860 vast forests of gutta-percha trees were found in Guiana, and ninny varieties of the tree flourish in the luxu riant forests of Brazil. An inferior quality is obtained from trees and climbers in Africa and Madagascar. There is also a variety known as caoutchouc gutteux, which combines many of the characteristics of gutta-percha and indin-ruhher. The gutta-percha of commerce comes chiefly from the Sunda Islands, Cochin-China, Cambodia, and Hindustan, Singapore being the chief shipping port. The different varieties on the market are designated by the place where they grew, the best being that coming from Macassar and Sarawak.
The present mode of obtaining the gutta-percha is a most destructive one, and attempts are being made in many countries to regulate by legislation the collection of the juice. The finest trees are selected and cut down, and the bark stripped off; between the wood and bark, a milky juice is found, which is scraped up into little troughs made of plantain-leaves. The milk, as it flows from the tree, is snow-white, but darkens on being exposed to the air. Like rubber, a thick cream forms on the top of the milk when allowed to stand. This is removed, molded into cakes, and thrown into boiling water, from which it emerges ready to be shipped. Unfortunately, the gath
erers do not hesitate to mix earth or other im purities in the cake to add to its weight, so that it is difficult to obtain the pure article.
It is imported in blocks and lumps of five to ten pounds weight, in various forms, chiefly large cakes, or rounded into gourd-like lumps. It has a very light, reddish-brown, or almost a flesh col or, and is full of irregular pores elongated in the direction in which the mass has been kneaded. It has a cork-like appearance when cut, and a pe culiar cheese-like odor. Before it can be used, it has to undergo some preparation. This con sists in slicing the lumps into thin shavings, which are placed in a deviling or tearing machine revolving in a trough of hot water. This reduces the shavings to exceedingly small pieces, which, by the agitation of the tearing teeth, are washed free from many impurities, especially fragments of the bark of the tree, which, if not separated, would interfere with the compactness of its texture, which is one of its most important qualities. The small fragments, when sufficiently cleansed, are kneaded into masses which are rolled several times between heated cylinders, which press out any air or water, and render the mass uniform in texture. It is then rolled be tween heated steel rollers into sheets of various thickness for use, or is formed into rods, pipes, or tubes. Hollow tubes are made in a machine similar to that which is used for making maca roni. Sometimes caoutchouc gutteux is mixed with the gutta-percha to make it more supple, or india-rubber to make it more elastic.
Gutta-percha was known in Europe long before its peculiar character and possible uses were un derstood. It was from time to time brought home by voyagers, in the form of drinking-bowls, which excited much curiosity on account of the material of which they were made. Some thought at a species of .india-rubber; others asserted it to be a kind •of wood, which they named mazer wood, from its use in making these drinking-cups.