BASES OF CINCHONA-BARK. 443 



medicament), crystallizes out of a hot saturated solu 

 tion of quinine, in dilute sulphuric acid, in long, shiny 

 prisms; as prepared in manufacturing establishments, 

 it usually forms a white, porous, light mass, consisting 

 of very fine and short needles, which have partially 

 lost their water of crystallization. It tastes exceed 

 ingly bitter ; is very difficultly soluble in water (in 780 

 parts at the ordinary temperature), more easily soluble 

 in alcohol, easily soluble in water containing sulphuric 

 acid, forming a blue, fluorescent liquid. Fuses like 

 wax, and, when more strongly heated, turns a beautiful 

 red, and is then carbonized. If an alcoholic solution 

 of iodine is added to a solution of this salt in acetic 

 acid, after a time large, thin plates, consisting of a 

 compound of quinine sulphate with iodine (herapa- 

 thite) separate. These crystals are almost colorless in 

 transmitted light ; in reflected light they have a beau 

 tiful, green color and a metallic lustre, and polarize 

 light like tourmaline plates. 



The biarid salt, C 20 H 24 F 2 2 .H 2 S(&amp;gt; -f 7H 2 0, crystallizes 

 in transparent, four-sided prisms ; is more easily soluble ; 

 and has an acid reaction. 



If chlorine water is added to a salt of quinine, and 

 then ammonia, it turns an intensely emerald-green 

 color. If, after the addition of chlorine water, a little 

 potassium ferrocyanide and then ammonia are added, a 

 deep red color makes its appearance. 



2. Cinchonine, C 20 H 2 W 2 0. Precipitated with am 

 monia, it forms a white, earthy mass. Crystallizes 

 easily from alcohol in shiny prisms. Insoluble in water 

 and ether, soluble in hot alcohol, less easily than qui 

 nine. 



The salts resemble the salts of quinine, but are more 

 easily soluble. They give no green color with chlorine 

 water and ammonia, but a yellowish-white precipitate. 



When heated with bromine or chlorine, substitution- 

 products of cinchonine are formed. Dibromicinchowne, 

 C 20 H 22 Br 2 N 2 0, is formed by heating cinchonine hydro- 

 chlorate with an excess of bromine, and, on dissolving 



