various Species of Cinchona. 1 3 7 



we add an excess of these re-agents, it is redissolved, and 

 the Hquor which results from it has a reddish brown colour. 



The solubility of this substance in alcohol singularly in- 

 creases on the application of heat. When this solvent is 

 saturated with it, it has a reddish brown colour and an ex- 

 tremely hitter taste. The addition of water precipitates from 

 it abxindantly a precipitate of a fine red colour, slightly in- 

 clining to pink. This alcoholic solution, exposed to the air 

 in an open vessel, crystallizes in needles in the manner of a 

 salt. 



The alcoholic solution, thus precipitated by water, retains 

 a. portion of the matter, which preserves to it a pink colour 

 and a sensibly bitter taste. It deposits this substance, in the 

 form of scales, of a reddish brown colour, by spontaneous 

 evaporation. 



The principle of cinchona insoluble in alcohol, dissolved 

 in water, filtered and abandoned to a spontaneous evapora- 

 tion in a warm place, thickens like a kind of syrup, and cry- 

 stallizes in the form of laminae, sometimes hexaedral, some- 

 times rhomboidal, and sometimes square, and slightly co- 

 /loured of a reddish brown : there always remains a portion of 

 thick liquor, which never crystallizes completely, and which 

 must be separated from it by decantation. 



By successive solutions and crystallizations this salt may 

 be obtained white and pure : T shall explain its properties 

 a little lower down. As to the substance which does not 

 crystallize, and which remains in the form of a mother wa- 

 ter, it presented to me all the characters of a mucilaginous 

 matter, in which there always remains a small quantity of 

 the salt I have mentioned, and which it is impossible to se- 

 parate from it by crystallization. 



Action of the Acids upon the Residues of Cinchona exhausted 

 hy successive IVushivgs. 

 The cinchonas in question, exhausted by water, still fur- 

 nish something to the acids. They act almost nearly in the 

 same maimer, i. e. their effect is confined to a simple solu- 

 tion, without producing any sensible change in the nature 

 of the principli s of cinclionas. 



I ought 



