ALKALOIDS. . 399 



Analytical reactions: 



1. Chlorine water added to the solution of a cinchonine salt pro- 

 duces a yellowish-white precipitate insoluble in excess of ammonia. 



2. Potassium ferrocyanide solution added to a neutral solution of 

 cinchonine produces a white precipitate soluble in excess of the re- 

 agent. Upon adding an acid to this solution a golden-yellow 

 precipitate is formed. 



3. With alkali hydroxides, carbonates, and bicarbonates, cincho- 

 nine salts form white precipitates insoluble in ammonia. 



Cinchonidine, C 19 H 22 N 2 O. An alkaloid isomeric with cinchonine; 

 soluble in 75 times its weight in ether. The sulphate is official. 



A mixture of equal parts of sugar and cinchonidine sulphate 

 heated in a dry test-tube causes a deposit of red oily drops on the 

 cool portion of the tube. The addition of 4 c.c. of a saturated aqueous 

 solution of phenol to 1 c.c. of a saturated aqueous solution of cin- 

 chonidine , sulphate causes a copious deposit of small crystals. 



Strychnine, Strychnina, C 2 ,H 22 N 2 O 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 containing 1 in 700,000. 

 It is nearly insoluble in water and in ether, soluble in chloroform 

 and in dilute acids. 



By dissolving it in sulphuric acid the official strychnine sulphate, 

 Strychnine sulphas, (C 21 H 22 N 2 O 2 ) 2 .H 2 SO 4 .5H 2 O, is obtained. 



Strychnine has strong basic properties and is one of the most power- 

 ful poisons known, one-quarter of a grain having caused death within 

 a few hours. 



Analytical reactions : 



1. Strychnine dissolves in sulphuric acid and nitric acid without 

 color. 



2. A fragment of potassium dichromate, drawn through a solution 

 of strychnine in concentrated sulphuric acid, produces momentarily a 

 blue, then brilliant violet color, which slowly passes to cherry-red, 

 then to rose-pink, and finally to yellow. This reaction may still be 

 noticed with 50 j, 06 grain of strychnine (Plate VII., 5). 



3. Sonnemchein's test. When to a very small quantity of strych- 

 nine, dissolved in a drop of sulphuric acid, some ceroso-ceric oxide is 

 added, and the mixture is stirred with a glass rod, a deep-blue color 



