GHATTI 451 



Constituents. The constituents of ghatti gum are, as far as is known, 

 similar to those of acacia. 



Uses. Ghatti gum is admirably adapted for pharmaceutical use ; 

 it has excellent emulsifying properties. 



TRAGACANTH GUM 



(Tragacantha) 



Source, &c. Tragacanth gum is a dried, gummy exudation from 

 the stem of Astragalus gummifer, Labillardiere (N.O. Leguminosce), 

 and other species of Astragalus. 



These plants are small, branching, thorny shrubs, about a metre 

 in height, and are natives of southern and eastern Europe and 

 especially of Asiatic Turkey and Persia, where they form one of the 

 most characteristic forms of vegetation. When the stem is incised 

 a gum exudes and dries, the form that it assumes being dependent 

 on the form of the incision, vertical slits yielding flat, ribbon-shaped 

 pieces and punctures vermiform tears. It is produced by the trans- 

 formation of the cell- walls of the pith and medullary rays into gum, 

 which easily absorbs water, and, swelling, exerts considerable pressure 

 on the surrounding tissue. When, therefore, the stem is wounded the 

 gum is forcibly pressed out, a piece about 2 cm. long being exuded in 

 half an hour ; it carries with it the starch grains present in the cells 

 in a more or less unaltered condition, and these are therefore a natural 

 constituent of the drug. 



Of the influences that induce gummosis of the cell-wall, nothing 

 definite is known. 



In some districts accidental wounds by grazing cattle appear to 

 suffice for the production of tragacanth. In Asiatic Turkey it is 

 collected chiefly in Anatolia and shipped from Smyrna ; in Persia 

 the Baktiari mountains, south of Ispahan, and the neighbouring 

 districts yield much tragacanth, which is conveyed from the Persian 

 Gulf ports to Bombay, and thence to Europe. The former variety 

 is known as Smyrna, the latter, which alone is official, as Syrian or 

 Persian. 



Description. Syrian or Persian tragacanth occurs in thin, flattened 

 curved, ribbon-shaped flakes of a translucent, horny appearance 

 and nearly colourless or faintly yellowish. The flakes are often 3 cm. 

 long and 1 cm. wide, and are marked with numerous concentric ridges, 

 conveying the impression that the gum has been exuded in successive 

 portions. The flakes break with a short fracture, are odourless and 

 almost tasteless. Soaked in cold water they swell considerably, 

 forming a gelatinous mass, but only about 8 or 10 per cent, dissolves. 



Smyrna tragacanth occurs in similar pieces in which, however, the 

 ribbon-like character is less pronounced, and which are more opaque 



