1140

ELEMENTS OF MATERIA MEDICA.

In 1805, Vauquelin (Ann. Chim. liv. 312) made an examination o ^proximate constituents of tragacanth. In 1815, Bucholz (Gmelin, # jcl. Chem. ii. 779), and in 1831 Guerin-Varry (op. supra cit■) pubn sproximate analyses of this gum.

Bucholz's Analysis.

Common gum. 57

Bassorin . 43

Gum Tragacanth . 100

Guerin■ Varry's Analysis.

Arabin . 53 30

Bassorin and starch .

Water.

Ashes...

Gum Tragacanth.

100 00

lobl®

1. Tragacanthin. Adragantin. Soluble gum, or arabin of Tragacanth.—The s ca j| e dgum of tragacanth is usually regarded as similar to gum Arabic, and hence it ,S i uC iotrarabine ; but it is distinguished by silicate of potash and perchloride of iron pr° j co )|olno change in it, and by a peculiar appearance of the precipitate produced with ^

qlloridf

of

(the precipitate is flocculent, and collects in a simple opaque, and mucouscommon with arabine it produces precipitates with diacetate of lead, protoehio'^tin, and protonitrate of mercury. Oxalate of ammonia detects in it a calcareous^ flt (|

2. Bassorin. Insoluble gum of Tragacanth. —The insoluble part of gum tra„ ter ,

is similar to that of gum Bassora, and hence is called Bassorin. It swells up i n py

3. Starch— Starch globules may be detected in the bassorin (when swollen “

thin,®

water) both by the microscope and by iodine.

According to Guibourt (Hist, des Drag. ii. 477) tragacanth contains neither a jjf.nor bassorine, but is essentially formed by an organized gelatiniform matter, r> iislerent to gum Arabic both m its physical and its chemical properties, and whichand divides in water, so as in part to pass through a filter. The insoluble p ar . p Jjjsgacanth is, according to the same authority, a mixture of starch and lignin, w a n4nothing in common with bassorine. Decandolle suggests that the iusolubi 1swelling of tragacanth in water may arise from the gummy matter being c °in cells.

11 u'bt*

Physiological Effects. —Like other gums, tragacanth is emodemulcent, and nutritive; but difficult of digestion. a cti vC

Uses. —Tragacanth, in powder, is used rather as a vehicle for a c rand heavy medicines (as calomel), than on account of its own r^Ljteffects. It is occasionally, however, taken as a sheathing or de®agent in irritation of the mucous membranes.

Administration. —Dose of the powder, 3 SS. to jij. - sC (l;

1. Pulvis Tragacantirh compositus, L. hi. (Tragacanth, bn ^Gum Arabic, bruised; Starch, of each siss.; Pure Sugar, 5iij-

Starch and Sugar together to powder, then having added the Tia£and Gum Arabic, mix them together).—Employed as a vehicleexhibition of active and heavy powders to children. Dose for an c3SS. to 5j. , ha P'

2. Mucilago Tragacanthje , E. Mucilago Gummi Tragacan V oU r(Tragacanth, 31 ].; Boiling Water , f*ix. “Macerate for tv ' e p^ e norhours, then triturate to dissolve the gum, and express through ugC J,calico,” E. —The Dublin College directs the powdered gum to 6 c j oS eand employs f ’3 viij. of water. Maceration is to be effected mvessel, until the gum is dissolved, and the mucilage then straiEmployed in making pills and lozenges; also to suspend heavy P ag a uas the metallic oxides, in water. It has also been recommend 6application to burns.