Existing accounts of the collection of galbanurn are imperfect and contradictory ; possibly different systems prevail in different localities. Buhse states that the gum-resin exudes freely and spontaneously from the lower part of the stem and the bases of the leaves. Geoffroy says that it is extracted by making large incisions in the stem at about 3 in. above the root, when it esCapes in drops, and at the end of a few hours has dried sufficiently to be collected. Landerer asserts that the stem is scarified, and a mussel-shell placed beneath to catch the exudation. The appear ance of the bulk of the galbanum of commerce favours the supposition that it is principally drawn from incisions in the roots, few samples occurring free from an abundance of root-fragments.
Galbanum is usually classified into two kinds, " tears" and " lump." The drops or tears of Levantine commonly adhere, so as to form a mass, generally compact and hard, but the Persian are occasionally soft to fluidity. Their size vo.ries from that of a lentil to that of a hazel-nut ; and their colour, from light-brown to yellowish or greenish. The odour is peculiar, aromatic, and not unpleasant ; the flavour, bitter, alliaceous, and objectionable. In some samples, the tears are dull and waxy, changing from light-yellowish to orange-brown by keeping, with little disposi tion to concrete, and a savin-like odour. The sp. gr. of the drug is about 1.212. It consists essentially of about 50-70 per cent. of soft resin, soluble in ether and alkaline leys (even milk of lime), but not entirely in carbon bisulphide ; 3-7 per cent. of volatile oil ; and 18-23 per cent. of a gum resembling bassorine in its solubility.
The so-called " Levant" galbanum enters Europe via., Trieste and Marseilles. Some is said to reach London from Bombay. Very large quantities pass into Russia by way of Astrakan, Orenburg, and Nijni-Novgorod, wrapped first in skins and then in mats, and each package weighing about 60-80 lb.
The uses of galbanurn are almost wholly medicinal (see Drugs, p. 811), though it is said to be an ingredient of some cements.
The approximate London market value of galbanum is 6d.-18. 3d. a lb.
Gamboge (Fn., Gomme Guile; GER., Gutti, Gummigutt).—Some account of this gum-resin has already been given under Pigments (see p. 1551). In addition to the species there indicated as affording the pigment, it would seem that a similar colouring matter is derived from Stalagmites ovalifolius in Ceylon, and from Vismiaguianensis, V. cayennensis, V. dealbata (laerezetra gum in Brazil), and V. sessiliflora in S. America, though none of these products is known in European oommerce.
The value of the gum-resin for both tinctorial and medicinal purposes is directly dependent upon the proportion of the re.in present. Analyses of commercial samples of " lump," " pipe," and " powder " gamboge, by Costelo, show:— The resin (" gambogio acid," C„H„04) is of bright reddieh-brovrn colonr, translucent, very brittle, and easily rubbed into a bright-yellow powder ; it is soluble in alcohol, ether, chloroform, earbon bieulphide, ammonia and potash leys, and partially in petroleum-benzine.
Ging and Kunnee.—Theee names are applied locally to two grades of gnm prodneed by Odeta Weller, in the Coromandel mountains and Travancore. The exudation is abundant and
spontaneous, and takes place from the bark of the tree, about April. The lst quality is white, and is called kunnee; of it, a man can gather about 2 lb. a day. The 2nd quality is black, end consiste nominally of what luta fallen to the ground, but is almost invariably mixed and Bold with that obtained from Conocarpus sp.; of this, one man can collect 10 lb. daily. A good specimen of the tree yields about 5 lb. of gum. It is ueed by dyers, cloth-printers, in ink, and as medicine. Samples sent into the London market for valuation were reported inferior to chironji (see p. 1633), and priced at 10-30s. a cwt., much fault being found with the large proportion of insoluble matters. It was etated that if imported here, it would probably be need only as an adulterant.
Specimens of gum-reein and pitchy resin attributed to the same source mut be regarded with doubt. It is to be regretted that more attention has not been paid to the exudations of (Mina Wudier. Dr. Dymoek calls the gum by the names shimptee and ntooi.
Guaiaeum (Fn., Garae; GER., GUajaCharz).—Thie well-known medicinal resin is obtained chiefly from Gu,aiacum officinale, and in minor quantity from G. sanctum. Both are natives of the W. Indies, notably San Domingo and Les Gonaives (see Timber—Lignum-vites). A small quantity of the reign is collected as a natural exudation in tears from the kerns of the trees, but a much larger proportion is extracted artificially. Thie is performed in eeveral ways. The simplest consiets in making incisions in the bark of the living tree. Another method is to eupport logs of the wood in a horizontal position, to make an incision at the centre, and then to ignite both ends of the log ; ae it burns, the resin escapee from the incision. A third plan ia to expose logs, which have been perforated endwise, to the influence of a brisk fire. A fourth ayetem is to bod fragments of the wood in water, wholie density has been increased by the addition of salt ; the resin melts out and forms a layer on the aurface of the water. The reain occurs commercially sometimes in globular teare 1-1 in. diem., but genentlly in masses, more or less aseociated with ddbris of the wood and bark. It ia brittle, with a clean glassy fracture, transparent and greeuish-brown iu thin pieoes. The powder ie grey while fresh, but soon becomee green by expoeure. The odour is baleamic; the flavour is slight, but leaves an irritating sensation in the throat. The sp. gr. is about 1.12. The fusing-point is 85° (185° F.), when a benzoin-like odour is emitted. The resin is soluble in alcohol, ether, ecotone, amylie alcohol, chloroform, creasote, cauetio alkaline leys, and clove-oil ; slightly iu other volatile oils, bonze', and carbon bisulphide. The commercial article is often much contaminated by impurities through carelessness in the collection. It is also adulterated with common pine-roein, and is itself mixed fraudulently with ecammony and jalap. Its uses are wholly medicinal (see Drugs, p. 811). It is imported almoat exclusively from San Domingo, whence the exports were 36,350 lb. in 1875, but only 3320 lb. in 1879, and 1830 lb. in 1880; in the two last yeare, the expert was entirely to the United States.