ALKALOIDS. 329 



6. Neutral solutions of quinine are precipitated by alkaline 

 oxalates. 



7. Quinine and its salts, when heated on platinum foil, burn 

 entirely away. 



8. Quinine and its salts form colorless solutions with concen- 

 trated sulphuric acid. A dark or red color indicates the presence 

 of other organic substances. 



Cinchonine, Cinchonina, C 20 H 24 N 2 = 308. This alkaloid is 

 found in cinchona bark in quantities varying from 0.5 to 3 per 

 cent. It crystallizes without water, forming white needles; 

 it is almost insoluble in water, soluble in 110 parts of alcohol or 

 in 370 parts of ether, readily soluble in diluted acids. 

 By dissolving the alkaloid in sulphuric acid is obtained : 

 Cinchonine sulphate, Cinchonine sulphas, (C 20 H 24 N 2 0) 2 H 2 S0 4 . 2H 2 O 

 = 750. It is a white, crystalline substance. Cinchonine differs 

 from quinine by its greater insolubility in ether, by its insolu- 

 bility in ammonia water, by not forming fluorescent solutions, 

 and by not giving a green color with chlorine water and 

 ammonia. 



Cinchonidme, C 2( ,H 24 N 2 0. An alkaloid isomeric with cincho- 

 nine; soluble in 75 times its weight of ether. The sulphate is 

 officinal. 



Quinidine, C 24 H 24 N 2 2 . Isomeric with quinine; it gives, like 

 the latter, a green color with chlorine water and ammonia, 

 and forms fluorescent solutions. Unlike quinine, it is not pre- 

 cipitated from neutral solutions by alkaline oxalates. 



Strychnine, Strychnina, C 21 H 22 N 2 2 = 334. This alkaloid is 

 found, together with brucine, in the seeds and bark of different 

 varieties of strychnos, and is generally obtained from nux 

 vomica. Strychnine is a white, crystalline powder, having an 

 intensely bitter taste, which is still perceptible in solutions con- 

 taining 1 in 700,000. It is nearly insoluble in water and in 

 ether, soluble in chloroform and in diluted acids. 



By dissolving it in sulphuric acid the officinal strychnine sul- 

 phate, Strychnines sulphas, (C 21 H 22 N 2 O 2 ) 2 .H 2 S0 4 .7H 2 O = 892, is ob- 

 tained. 



