442 BASES OF CINCHONA-BARK. 



Preparation. Coarse cinchona powder is repeatedly 

 macerated with water containing hydrochloric acid ; 

 the filtered solution mixed with sodium carbonate; 

 the precipitate washed, pressed, and dried. It contains 

 quinine and cinchonine, calcium tannate, and other 

 substances. Both bases are extracted with boiling 

 alcohol ; the filtered, strongly colored solution neutral- 

 ized with dilute sulphuric acid ; and the alcohol dis- 

 tilled off. On cooling, quinine sulphate crystallizes 

 out, which is obtained colorless by treatment with 

 animal charcoal, and recrystallization. From the col- 

 ored mother-liquor cinchonine sulphate is obtained. 

 To isolate the bases their salts are dissolved in water, 

 and precipitated with ammonia. 



1. Quinine, C 20 H 24 2 2 -f H 2 0. Precipitated by 

 ammonia, it forms a white, earthy mass ; and it is diffi- 

 cult to obtain it in a crystalline form even from alco- 

 hol. It is fusible, w r ith loss of water, forming a resin- 

 ous mass; tastes very bitter; reacts alkaline; soluble 

 in 1667 parts water of 20, in 900 parts boiling water, 

 moderately soluble in ether, very easily soluble in 

 alcohol. 



Combines with one and with two molecules of a 

 monobasic acid, forming salts. Most of these are crys- 

 tallizable, have a very bitter taste, and are precipitated 

 by oxalic acid ; also by alkalies, platinum chloride, and 

 tannic acid. 



Quinine hydrochlorate. The salt, with one mole- 

 cule of hydrochloric acid, C 20 H 24 X 2 2 HC1 + liH 2 0, 

 forms long prisms, of a silky lustre ; the salt, with 

 two molecules of the acid, is converted into the first 

 salt by the action of water. Platinum chloride gives 

 a bright-yellow precipitate in the hydrochloric acid 

 solution, which, after a time, becomes crystalline and 

 orange-red (C 20 H 24 N 2 2 .2HCl.PtCl 4 + H 2 0); mercury 

 chloride gives a white precipitate. 



Quinine sulphate, 2(C 20 H 24 N 2 2 )H 2 S0 4 + 

 (the principal form in which quinine is employed as a 



