Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/358

Rh 338 G U T T A P E K C H A with a girth of 20 feet at a distance of 14 feet from the base, and may yield 50 to 60 Ib of gutta percha, which loses in six months about 35 per cent, of its weight in drying. The methods of extracting the gutta percha are much the same amongst the Malays, Chinese, and Dyaks. The trees are cut down just above the buttresses, or banees, as they are called; and for this purpose a staging about 14 to 16 feet high is erected. The tools used in felling are either &quot; billiongs&quot; or &quot; parangs.&quot; A billiong is a kind of axe used by the Malays in felling, building, &c. The blade is of a chisel -like form, and the tang is secured at right angles to a handle by means of a lashing of &quot; ratan &quot; or cane. The Chinese sometimes use an axe perfectly wedge-shaped. The parang looks more like a sword-bayonet, and in the hands of a Malay is a box of tools in itself, as with it he can cut up his food, fell a tree, build a house, or defend himself. When the tree is felled the branches are speedily lopped off, to prevent the ascent of the gutta to the leaves. Narrow strips of bark, about an inch broad and 6 inches apart, are then removed, but not all round the tree, as its underpart in its fall becomes buried in the soft earth, much sap being thus lost. Some natives beat the bark with mallets to accelerate the flow of milk or gutta. The milk flows slowly (changing colour the while) and rapidly concretes, and, according to its source, may vary from yellowish-white to reddish or even brownish in hue. The gutta as it flows is received into hollow bamboos, doubled- up leaves, spathes of palms, pieces of bark, cocoa-nut shells, or in holes scraped in the ground. If the quantity obtained is small, it is prepared on the spot by rubbing it together in the hands into a block, in one end of which a hole is made to carry it by. In this state it is known in the market as &quot; raw gutta &quot; or &quot; gutta muntah.&quot; If water gets mixed with the juice, the gutta becomes stringy and is considered deteriorated, but after boiling appears quite as good. Sometimes the gutta is kept in a raw state for a month or two, and then undergoes the next step in the pre paration, that is, boiling. The boiling is generally con ducted in a &quot;kwali&quot; or pan of cast or hammered iron, of about 15 inches in diameter and 6 inches deep. The boiling is either simply with water, or with the addition of lime juice or cocoa-nut oil. If one pint of lime juice be added to three gallons of gutta juice, the latter coagulates immediately on ebullition. On arriving at the port of shipment the gutta, before exportation, generally undergoes examination and classifica tion into parcels, according to quality. As received in the &quot; godowns &quot; or warehouses it presents great diversities in condition, shape, size, and colour, from crumbling, hardly coherent, whitish or greyish &quot;raw&quot; or &quot;getah muntah&quot; fragments, to reddish or brownish blocks as hard as wood. Sometimes it is made up into all manner of grotesque shapes of animals, and it is nearly always largely adulter ated with sago-flour, sawdust, clay, stones, &c. The Chinese are great adepts in assorting and classifying gutta, and frequently prepare from different varieties a certain &quot;stand ard sample&quot; by cutting or chopping the material into thin slices and boiling with water in large shallow iron pans, keeping the contents constantly stirred with poles, and adding good gutta percha and even cocoa-nut oil to give a better appearance. When sufficiently boiled the gutta is pressed into largo moulds, and is then ready for shipment. This process of reboiling is wholly unnecessary, and in some cases is done only to get rid of stuff which has no right to be called &quot;gutta percha.&quot; The amount and valuo of gutta percha imported into Great Britain in 1875-77 were as follows : 1875. 1876. 1877. Cwts 19,686 21,558 26,359 Value 149,684 163,441 238,327 The price of gutta percha ranges from 4d. to 3s. per ft), according to quality and demand. History. The early history of the use of gutta percha is somewhat obscure ; the Malays and Chinese are said to have long known and used it. One of the earliest notices of it in England occurs in a catalogue of the collection of the famous Tradescants. 1 Dr Montgomerie, a surgeon in the East India Company s service, was the first to direct atten tion to gutta percha as likely to prove of great utility in the arts and manufactures. Having observed the substance in Singapore in 1822 in the form of whips, he commenced experimenting with it. In 1842, being again stationed at Singapore, he followed up the subject, and his recommenda tion of it to the medical board of Calcutta as useful for making of splints and other surgical apparatus met with high approval. He also sent specimens, with relative in formation, to the Society of Arts of London, which society warmly took up the subject, and on Montgomerie s return to England in 1844 presented him with its gold medal. Some have claimed the honour of introducing gutta percha to the notice of the commercial world for Dr (afterwards Sir) Jos6 D Almeida, who sent a specimen merely as a curiosity to the Royal Asiatic Society in 1843, but careful investigation clearly decides the question of priority in favour of Montgomerie. The Society of Arts having requested him to lay before them the result of his experi ments, he delivered a lecture in the autumn of 1844, and many patents were at once taken out, the chief being those of Mr C. Hancock, Mr Nickels, Mr Keene, Messrs Barlow and Forster, Mr E. W. Siemens, and others. After this the substance soon came into general use. 2 Properties. Gutta percha, like many other milky juices, occurs in the laticiferous tissue of the plant, which exists in greatest abundance in the middle layer of the bark. See BOTANY, vol. iv. p. 87. Gutta percha is resolvable into two resins, albin and ftuavil. Like caoutchouc or india rubber, it is a hydrocarbon ; Soubeiran gives its composition as carbon 87 80 and hydrogen 12 20. In commercial gutta percha we have this hydrocarbon or pure gutta, plus a soft resin, a resultant of oxidation of the hydrocarbon. M. Payen gives the following analysis of commercial gutta percha : Pure gutta (milk-white in colour arid fusible), 75 to 82 per cent. Resins soluble in boiling alcohol : 1. Crystalbin or albin (Co H 3a O s ), white, and crystallizing out of the alcohol as it cools, 6 to 14 per cent. 2. Fluavil (C 20 H 3a O), yellow, falling as an amorphous powder on the cooling of the alcohol, 6 to 14 per cent. It is thus apparent that the change of pure gutta into a resin-like mass takes place naturally if means be not taken to stop it. Many a good parcel has been thus lost to commerce, and the only remedy seems to be thorough boiling. as soon after collecting as possible. It must be remembered too that, in cutting through the bark to arrive at the laticiferous vessels, many other vessels and cells become ruptured, containing tannic and gallic acids, &c. , and the presence of these no doubt accelerates oxidation. In opening bottles of the milky juice a turbidity and effervescence are often noticed, owing to the formation of a brownish liquid, the colour being probably due to the presence of gallic acid. In improperly prepared blocks of gutta also, these foreign substances induce the presence of a brown fermented and putrid liquid, which decomposes the internal mass. Many of these substances, being soluble in water, are removable by the process of boiling. Gutta percha as met with in commerce is of a reddish or yellowish hue, but when quite pure is of a greyish-white colour. In this 1 In the Museum Tradescantianum ; or, a Collection of Varieties preserved at South Lambeth,, neer London, by John Tradescanl,. . . London, MDCLVI., the following entry occurs (p. 44): &quot;VIII. Variety of Rarities. The plyable mazer wood, being warmed, will work to any form. &quot; This museum became the nucleus of the Ashmolean Museum at Oxford. The word &quot;mazer,&quot; variously spelt, often occurs in early English poetry, and is specially mentioned in old catalogues and wills. It is by no means impossible that mazer cups may have been made of gutta percha, as its lightness, strength, and non-liability to fracture would recommend it; and curiously enough one of the vernacular names of the tree yielding gutta percha is &quot;mazer wood tree.&quot; 2 See Collins on &quot; Gutta Percha&quot; in British Manufacturing Industries (Stanford & Co.), and the very interesting volume of Specifications of Patents in Caoutchouc, Gutta Percha, &c. issued by the Patent Office.