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 biacid salt, C 20 H 24 ]Sr 2 2 .H 2 S0 4 + 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 24 N 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. Dibromicinchonine, 

 C 20 H 22 Br 2 ]Sf 2 0, i s formed by heating cinchonine hydro- 

 chlorate with an excess of bromine, and, on dissolving 



