CRUDE DRUGS. 645 



Combretaceae) (the latter being the source of the so-called Ghatti 

 gum), yield gums which, while resembling true acacia, do not 

 respond to the tests given above. 



An artificial gum has been prepared by heating starch with 

 sulphuric acid in an autoclave, the resulting product being neut- 

 ralized, washed and then dried. It is said to resemble acacia in 

 appearance and adhesiveness. 



The powder, while sometimes adulterated with dextrin and 

 rice starch, is more frequently mixed with inferior gums, espe- 

 cially the Mesquite gum. The tears of Mesquite gum are nearly 

 smooth, light yellowish-brown to dark-brown, more or less opaque, 

 but translucent and glassy when fractured. The powder is of a 

 whitish or grayish-white color. The gum is further distinguished 

 by not giving precipitates with lead sub-acetate, ferric chloride 

 and sodium borate. Mesquite forms an adhesive mucilage and 

 can be used as an emulsifying agent. 



MASTICHE.— MASTIC.— The dried, resinous exudation 

 from Pistacia Lentisciis (Fam. Anacardiacese), a large shrub 

 (p. 321) indigenous to the Mediterranean region. The resin 

 exudes through incisions made in the bark, and when dry is col- 

 lected. The chief source of supply is the island of Scio. 



Description. — Somewhat globular or ovoid tears 3 to 7 mm. 

 long, pale yellow or greenish-yellow, translucent, having a glass- 

 like luster, comparatively free from a whitish dust; brittle; frac- 

 ture conchoidal, becoming plastic when chewed ; odor slight, bal- 

 samic ; taste mild, terebinthinate. 



Mastic is completely soluble in ether, acetone and volatile 

 oils. It is almost completely soluble in alcohol, the solution giv- 

 ing an acid reaction with litmus paper. 



Constituents. — About 90 per cent, of a resin, consisting of 

 a-resin (mastichic acid), which is soluble in alcohol, and ;8-resin 

 (masticin), which is insoluble in alcohol; a volatile oil, i to 2.5 

 per cent., with the balsamic odor of the drug and consisting chiefly 

 of d-pinene. A small quantity of a bitter principle is also present, 

 which is soluble in hot water and is precipitated by tannin. 



Allied Plants. — Various other species of Pistacia found in 

 India and .Northern Africa yield resins resembling mastic. Amer- 

 ican mastic is obtained from the Peruvian Peppertree (Schinns 



