560 CINCHONA QUININE 



epidermis, and a smooth pale red inner surface ; and 

 besides quinine and quinidine, contain a special alkaloid, 

 cinchonamine, but no cinchonidine (Phillips). 



PROPERTIES. The cinchona barks occur in quills, stripped 

 from the smaller branches, and curled into single or double 

 rolls, and in flat pieces from the larger branches or trunk. 

 They are dried in the sun, or on hurdles over fires. Their 

 colour varies from deep yellow to red-brown, and is deepened 

 by moisture. They have a faint odour, and a bitter, usually 

 astringent taste. They are soluble in cold and hot water, 

 and in alcohol ; their best solvents are alcohol (70 per cent.), 

 and diluted acids. The tests of quality and value are the 

 general appearance, fracture, colour, odour, taste, and per- 

 centage of the alkaloids, which are the active principles. 



COMPOSITION. Besides ordinary plant constituents 

 lignin, starch, gum, resin, mineral matters, with traces of 

 a volatile oil cinchona bark contains (1) a series of active 

 alkaloids ranging from 3 to 5 per cent. ; (2) chinic and 

 chinovic acids, with which the alkaloids are naturally 

 united, but which have no very marked physiological 

 actions ; (3) tannins, recognised as cincho-tannic acid, 

 constituting 1 to 3 per cent, of the bark, and conferring 

 astringency ; (4) a glucoside, chinovin ; (5) a colouring 

 matter, cinchona red. 



QUININE (C 20 H 24 N 2 2 ) is present in all the cinchona and 

 Remijia barks. It is in the form of sulphate that quinine 

 is generally prescribed in this country. From a watery 

 solution of the sulphate the alkaloid may be precipitated 

 by ammonia. It occurs in delicate acicular crystals, inodor- 

 ous and intensely bitter. It requires for solution 900 parts 

 of cold water, but is readily soluble in alcohol, ether, 

 chloroform, ammonia, and diluted acids. It forms colour- 

 less, bitter, crystallisable salts, remarkable, like the alka- 

 loid, for tonic and febrifuge properties. Quinine and its 

 salts turn a ray of polarised light to the left. Aqueous 

 solutions, acidulated, even when extremely diluted, exhibit 

 blue fluorescence. Treated with chlorine or bromine 

 solution, and then with a drop of liquor ammoniae, a green 

 coloration is produced. 



QUINIDINE, is isomeric with quinine, but crystallises in 



