Astragalus gummifer, Labrillardie're, or other Asiatic species. The dried gummy exudation.

Habitat. W. Asia -- Asia Minor, Armenia, Kurdistan, Persia, Syria, Greece; mountainous districts.

Syn. Trag., Gum Tragacanth, Goat's Thorn Gum, Doctor's Gum, Hog Gum; Fr. Gomme Adragante; Ger. Traganth.

Astrag'a-lus. L. fr. Gr. ..., bone, + ..., milk -- i.e., the milky then horny exudation, or from the seed squeezed into a square-like form similar to vertebrae (...) in some species.

Gum'mif-er. L. gummi, gum, + ferre, to bear -- i.e., plant produces gum.

Trag-a-can'tha. L. fr. Gr....A goat, + ..., thorn -- a goat thorn -- i.e., plant thorny like goat's head, and hedges made of it resist their onslaughts.

Trag'a-canth, natively called first: "gum adragant," then "gum dragant," next "gum dragan," finally "gum dragon."

Plant

Shrub .6-1 M. (2-3 degrees) high; stem naked with many stragglling, much ramified branches; bark reddish-gray, rough, and marked with leaf-scars, young twigs woolly; leaves 3 Cm. (1 1/5') long, closely placed, pinnate, rachis hard, stiff, persistent for some years as a woody spine, yellow, very sharp-pointed; leaflets 10-15 pairs, 3 Mm. (1/8') long, obovate, grayish-green; flowers small, pale yellow; stamens 10, upper one free, others united in a sheath; fruit small, oblong pod, covered with white hairs; seed 1, reniform, smooth, pale brown. GUM (tragacanth), in flattened, lamellated, frequently curved fragments, straight or spirally twisted pieces, .5-2.5 Mm. (1/50-1/16') thick, whitish, brownish, translucent, horny; fracture short, rendered more easily pulverizable by heat (50 degrees C.; 122 degreesF.); inodorous; taste insipid, mucilaginous.

Powder

whitish, forming with water a translucent mucilage -- numerous starch grains, .003-.025 Mm. (1/8325-1/1000') broad, occasional 2-4 compound, many swollen and more or less altered, due to excessive heat used in drying before powdering, by which it loses 15 p.c. Tests: 1. Add 1 Gm. To 50 cc. of distilled water -- swells and forms a smooth, nearly uniform, stiff, opalescent mucilage free from cellular fragments (Indian gum -- uneven mucilage with few reddish-brown fragments, separating on stirring in coarse, uneven strings). 2. Shake 2 Gm. with 100 cc. of water, when fully swollen and free from lumps add 2 Gm. Of powdered sodium borate, shake until dissolved -- mucilage does not lose transparency, change consistency, or appear slimy or stringy on pouring, even after standing 24 hours (abs. of foreign gums). 3. Boil 1 Gm. with water 20 cc. until a mucilage results, add hydrochloric acid 5 cc. Boil for 5 minutes -- no pink or red color develops (abs. of Indian gum). Solvents: hot water; cold water best. Dose, gr. 5-30 (.3-2 Gm.).

Astragalus gummifer - natural size of branch).

Adulterations

Cherry Gum (cherry, almond, plum, etc.) -- in irregular brownish nodules, insoluble portion not identical with bassorin; Indian (Bassora, Kutera, Hogg) Gum, Persia -- broken up in Smyrna and mixed with tragacanth; occurs in yellowish-brown (sometimes whitened with lead carbonate), angular, tasteless masses, swelling with water; Cashew Gum -- brownish-yellow, translucent, iridescent, partly soluble in water.

Commercial

Tragacanth is not a simple plant juice, but a degenerative product due to the transformation of the cell-walls of pith and medullary rays in the stem and older branches, and exudes spontaneously, July-August, through natural, or artificial punctures, longitudinal and transverse incisions (near the base of stem) into the medullary part which alone yields juice; it only flows at night, the shape of opening and rate determining its final congealed outline, the time of hardening for collection (1-2 weeks, dry weather 3-4 days) governing its color -- white if congealed rapidly, yellow to brown if slowly, from long exposure to changeable weather--heavy rains darkening and washing it off upon the ground causing admixture of impurities; the surface lines indicate the daily concretion while the whiter and more translucent possess greatest value. There are several varieties: 1. Flake (Leaf, Smyrna), usually in broad, thick, yellowish flakes, prominently ridged; the ribbon-like and white flakes are produced in Kurdistan, Persia, often being designated as Syrian; 2, Vermiform (Vermicelli), in very narrow contorted string-like pieces, or confluent coils; 3, Common (Sorts), called in Europe traganton, being the result of spontaneous exudation and incidental collection while gathering higher grades; occurs in tear-like pieces, rounded or irregular, brownish, waxy, and, like the preceding varieties, encloses starch. Enters commerce from ports of Asia Minor (Smyrna, Constantinople), Persian Gulf, Bagdad, etc.

Constituents

Cellulose, Soluble gum, Bassorin (traganthin, adraganthin), CHO, Polyarabinantrigalactan-geddic acids, Starch nitrogenous matter, a-tragacanthan-xylan-bassoric acid, xylan-bassoric acid, bassoric acid, -tragancanthan-xylan-bassoric acid, ash 3.5 p.c. (more than one-half being calcium carbonate).

Cellulose. -- The portion of gum insoluble in boiling water, in cold diluted acids and aklalies; when treated with boiling diluted sulphuric acid yields arabinose, and a cellulosic residue which is soluble in ammonia and bromine.

Soluble Gum. -- Not identical with arabin, although its solution is precipitated by alcohol and ammonium oxalate; yields a series of gum acids having the nature of the "geddic acids." but are levorotatory, whereas geddic acids are dextrorotatory.

Bassorin. -- This is an acid-soluble in hydrochloric acid, ammonia water; when acted upon by an excess of alkali yields a barium salt and two isomeric acids -- a- and -tragacanthan-xylan-bassoric acid, the former soluble in cold water and yielding sparingly soluble salts of barium, calcium and silver; when digested with diluted sulphuric acid yields trgacanthose and xylan-bassoric acid, which when further acted on by 5 p.c. sulphuric acid yields xylan and bassoric acid.

Preparations

1.  Mucilago Tragacanthae.  Mucilage of Tragacanth.  (Syn., Mucil, Trag.; Fr. Mucilage de Gomme Adragante; Ger. Traganthschleim.)

Manufacture

6 p.c. Mix glycerin 18 Gm. With water 75 cc. in a tared vessel, heat to boiling, remove heat, add tragacanth 6 Gm., macerate 24 hours, stirring occasionally, add water, q.s. 100 Gm., heat until uniform consistence, strain forcibly through muslin.  Dose, 3j-2 (30-60 cc.).

2, Glyceritum Tragacanthae, N.F., 12.5 p.c., + glycerin 77.5, water 18.5.  3.  Pilulae Ferri Carbonatis, 1/6 gr. (.01 Gm.).  4.  Trochisci Acidi Tannici, 1/3 gr. (.02 Gm.).  5.  Trochisci Ammonii Chloridi, 1/3 gr. (.02 Gm.)  6.  Emulsum Olei Morhuae cum Malto, N.F., 3/10 p.c.  7.  Stili Acidi Salicylici, N.F., 5 p.c.  8.  Syrupus Trifolii Compositus, N.F., 1/10 p.c.  9.  Trochisci Eucalypti Gummi, N.F., 1 gr. (.06 Gm.).  10.  Trochisci Ulmi, N.F., 1/6 gr. (.1 Gm.).

Unoff. Preps.: Pills, Troches -- various kinds.

Properties

Demulcent, emollient, protective, nutritious.

Uses

Was not known to the Greeks until 4th-5th century, when its uses were as now -- expectorant, for cough, hoarseness, similar to acacia; its superior adhesiveness over the latter renders it a better protective in excoriated surfaces, ulcers, burns, etc.  Employed largely for suspending resins, oils, heavy powders, etc., in emulsion.  Also to cohere pills (paste: 3j + glycerin 3j; 4 Gm., + 30 Gm.) troches, etc.; its partial insolubility in the stomach restricts somewhat its popularity.

Allied Plants

1.  Astragalus bae'ticus. -- Mediterranean basin; seed used for coffee.  A. exsca'pus; C. And S. Europe, mountains; root mucilaginous, astringent, bitter, diuretic.  A. glycyphyl'los, Europe; leaves and seed sweetish, diuretic. A. Crotala'riae, Loco Weed, Rattle Weed, and A. Mollis'simus, N. America (Cal., Neb., Tex.); poisonous to cattle, horses, etc., causing spinal tetanic action.