244 LEGUMINOS.E 



HABITAT. Western Asia. 



DESCRIPTION or DRUG. The flake tragacanth comes in transversely 

 lined, curved, and contorted bands, somewhat resembling fragments 

 of oyster shell, but tough and horny; color whitish or yellowish, 

 translucent. Taste insipid, sometimes faintly bitterish; inodorous. 

 It is difficult of pulverization, made less so, however, by the use of a 

 warm mortar. It does not dissolve in water, but swells up and forms 

 a thick, gelatinous mass. 



VARIETIES. Very narrow bands or strings variously coiled. Tragacanth 

 in sorts stratified or nodular, conical and subglobular pieces, more or 

 less brown, often adulterated with the gum of the almond and plum 

 trees. 

 Powder. Elements of: See Part iv, Chap. I, B. 



CONSTITUENTS. Traganthin or bassorin, CeHioOs, constituting about 

 43 per cent., swelling up in water, but not dissolving; and arabin, 

 the calcium salt of gummic acid, soluble in water, but not identical 

 with the arabin or arabic acid of acacia. Ash, not more than 3.5 

 per cent. 



ACTION AND USES. Used as a demulcent, but rarely, however, on account 

 of its insolubility. Chiefly used in pharmacy to give consistence 

 to lozenges, etc. 



OFFICIAL PREPARATION. 



Mucilago TragacanthaB (6 per cent.). 



257. CATECHU. CATECHU 



An extract prepared from the heart-wood of Aca'cia cat'echu Linnet 



BOTANICAL CHARACTERISTICS. Small tree with straggling, thorny branches, 

 and compact, dark red wood. Leaves bipinnate; petiole angular, with prickles 

 on its under side. Flowers pale yellow. Legume about three-seeded. 



SOURCE. The tree is common in most parts of India and Burmah, where the export 

 of cutch forms, next to the sale of timber, the most important item of forest 

 revenue. It abounds in the forests of tropical Eastern Africa, but in many 

 places where the tree abounds it is only valued for its wood. In compara- 

 tively few regions is any extract manufactured. From Acacia suma, a nearly 

 related species growing in Southern India, catechu is also made. The extract 

 from these two species of acacia furnishes a variety of catechu, but a catechu 

 formerly prescribed as Catechu pallidum (pale catechu), gambir, is official in 

 the present Pharmacopoeia and is described as follows: 



GAMBIR 



GAMBIR (CATECHU) 



An extract prepared from the leaves and twigs of Ourouparia Gambir (Hunter) 

 Baillon (Pam. Rubiaceae). 



Irregular masses of cubes about 25 mm. in diameter; externally 



