CORTEX CINCHONiE. 361 



rated from the other alkaloids of bai'k by a solution of iodide of 

 potassium which will precipitate the hydriodate. According to Hesse 

 (1873), quinidine is further characterized by the fact that its sulphate 

 is soluble in 20 parts of chloroform at 15° C, the sulphates of the other 

 cinchona-alkaloids being far less soluble in that liquid. The common 

 medicinal sulphate of quinine, e.g., requires for solution 1000 parts of 

 chloroform. 



3. CinclioniTie. — This alkaloid forms crystals which are always 

 anhydrous ; they fuse at 257° C, and require about 400 parts of ether 

 and 120 of spirit of wine for solution. Cinchonine further differs from 

 quinine by its dextrogyre power, its want of fluorescence, and its non- 

 susceptibility to the thalleioquin test. Its hydriodate is readily soluble 

 in water, and stiU more so in alcohol whether dilute or strong. 



4. Cinchonidine — forms anhydrous crj'stals melting at 206° C, 

 soluble in 76 parts of ether, or 20 of spirit of wine, then aflbrding 

 levogyre liquids, devoid of fluorescence, and not acquiring a green 

 colour (thalleioquin) by means of chlorine water and ammonia. Hydro- 

 chlorate of cinchonidine forms pyramidal crystals of the monoclinic 

 system, very different from the hydrochlorates of the allied alkaloids. 



5. Quitiamine. — The crystals are anhydrous, fuse at 172" C, and 

 form at a temp, of 20°, with 32 parts of ether or 100 parts of spirit of 

 wine, a dextrogyre solution. Quinamine is even to some extent soluble 

 in boiling water, and abundantly in boiling ether, benzol, or petroleum 

 ether. The solutions of quinamine do not stand the thalleioquin test, 

 nor do they display fluorescence ; in acid solution, the alkaloid is liable 

 to be transformed into an amorphous state. Quinamine moistened 

 with concentrated nitric acid, assumes like paytine a yeUow coloration. 

 Its hydriodate is readily soluble in boiling water, but very sparingly 

 in cold water, especially in presence of iodide of potassium, in which 

 respect it is allied to quinidine as well as to paytine. 



The more important properties of the Cinchona-alkaloids may be 

 summarized as follows : — 



a. Hydraied crystals are formed by . . . Qainine, Qninidine, (or Conquinine). 

 No hydraied crystals by Cinchonine, Cinchonidine, Quinamine. 



Sparingly soluble in ether Cinchonidine. » 



Almost insoluble in ether Cinchonine. 



c. Levogyre solutions aflForded by . . . Quinine, Cinchonidine. 



j-j , 1 1^ -L. S Cinchonine, Quinidine, Quinamine, Con- 



Dexfroflryre solutions by j quinamine,lnd the aiiorphous alkaloids. 



d. Thalleioquin is formed by Quinine, Quinidine, and also by Quinicine. 



Thalleioquin cannot be obtained from \ Cin^homne, Cinchonidine. Quinamine, nor 

 ^ ( from Cinchonicme. 



e. Fluorescence is displayed by solutions of Quinine, Quinidine. 



No fluorescence in solutions of pure . . Cinchonine, Cinchonidine, Quinamine. 



Proportion of Alkaloids in Cinchona Barks — This is liable to 

 very great variation. We know from the experiments of Hesse (1871), 

 that the bark of C. pubescens Vahl is sometimes devoid of alkaloid.* 

 Similar observations made near Bogota upon C. pitayensis Wedd., G. 



» BericlUe der DeuUehen Cfiem. GeseUscha/l zu BerUn, 1871. 818. 



