586 VEGETABLE DRUGS 



Preparations. — Mucilago acacise, U. S. & B. P. (34 per 

 cent., U. S.), and sjrupus acacise, U. S. P. (25 per cent.) 



Dose. — Ad lib. 



Action and Uses. — Gum arable is but slightly nutritious. 

 It is a useful demulcent in covering and protecting inflamed 

 mucous membranes of the upper respiratory and digestive 

 tracts. It may be given freelyin water, but large quantities 

 may undergo fermentation and cause indigestion and diar- 

 rhoea. A 10 per cent, aqueous solution is sometimes injected 

 into the bladder, vagina or rectum in inflammation of these 

 parts. Acacia is chiefly of value in medicine for the prepara- 

 tion of mixtures, emulsions, pills, balls and electuaries. 

 About 3 iii- of mucilago acacise are required to suspend § i. 

 of oil or resinous tincture. Acacia is sometimes prescribed 

 in genito-urinary irritation. Animals will voluntarily drink 

 aqueous solutions. 



Tragacantha. Tragacanth. (U. S. & B. P.) 



Synonym. — Gomme adragante, Fr. 



A gummy exudation from Astragalus guinmifer Labil- 

 lardiere, and from other species of Astragalus (nat. ord. 

 Leguminosae). 



Habitat. — Asia Minor. 



Properties. — In narrow or broad bands, more or less 

 curved or contorted, marked by parallel lines or ridges; 

 white or faintly yellowish, translucent, horn-like, tough, and 

 rendered more easily pulverizable by a heat of 122° F. 

 Yery sparingly soluble in water, but swells into a gelatinous 

 mass which is tinged blue with iodine. 



Constituents. — 1, arabin, 53.3 per cent., not identical with 

 arabin of acacia, however ; 2, bassorin (CgHioOg), 33.1 per 

 cent., a gum, swells up with water but does not dissolve ; 3, 

 starch ; 4, ash. 



PREPAEATION. 



Mucilago Tragacanthce, Mucilage of Tragacanth. (U. S. & B. P.) 

 Tragacanth, 6; glycerin, 18; water to make 100. (U. S.) 

 Dose.— Ad. lib. 



