CRUDE DRUGS. 519 



Red Cinchona. — Usually in double quills or rolled pieces 

 (Fig. 226) cut into lengths from 25 to 40 cm. long, 15 to 20 mm. 

 in diameter, bark 2 to 5 mm. thick ; outer surface reddish or dark 

 brown, with grayish patches of foliaceous lichens, longitudinally 

 wrinkled, with few usually widely separated transverse fissures ; 

 inner surface reddish-brown, distinctly striate ; fracture smooth in 

 periderm, in inner bark with projecting bast fibers ; odor distinct ; 

 taste bitter, astringent. 



C.^LiSAYA Bark. — Gray or brownish-gray, with numerous 

 patches of foliaceous lichens, having brownish-black and reddish- 

 brown apothecia, and numerous transverse fissures, which give 

 the bark a very characteristic appearance. 



The trunk bark is comparatively thick, while renewed bark is 

 comparatively smooth and uniform in color. 



Inner Structure. — See Figs. 227; 299, B; 307; 307a. 



Constituents. — A large number of alkaloids have been iso- 

 lated from this drug, of which the most important are quinine, 

 quinidine, cinchonine and cinchonidine. The total alkaloids 

 amount to about 6 or 7 per cent., of which from one-half to two- 

 thirds is quinine in the yellow barks, whereas, in the red barks, 

 cinchonidine exists in greater proportion. Quinine occurs in 

 small crystals which are sparingly soluble in water, soluble in 

 alcohol and readily form crystallizable salts with acids. On the 

 successive addition of dilute sulphuric acid, bromine or chlorine 

 water and ammonia water the solution becomes of an emerald- 

 green color (thalleioquin). Quinidine, an isomer of quinine, 

 crystallizes in rhombohedra or monoclinic prisms which are nearly 

 insoluble in water and otherwise conforms to the characteristics 

 given for quinine. The solutions of quinidine are, however, dex- 

 trogyre, while those of quinine are Isevogyre. Cinchonine sep- 

 arates in lustrous prisms or needles which are nearly insoluble in 

 water, and does not give the thalleioquin test, but forms a white 

 precipitate upon the addition of dilute sulphuric acid, bromine 

 water and ammonia. Cinchonidine crystallizes in prisms and 

 resembles cinchonine in many of its properties. Its solutions, 

 however, are Isevogyre, while those of cinchonine are dextrogyre. 



The other important alkaloids of Cinchona which have been 

 separated are: Quinamine, hydroquinine, hydroquinidine, hydro- 



