ON VARIOUS SPECIES OP CINCHONA. £07 



of these reagents be added, it is redissolved, and the solution 



has a brown red colour. 



The solubility of this substance in alcohol is singularly in- Heatgr«atly 



creased by heat. When the menstruum is saturated with it, J n f ceases its so. 



i . i . • ,ir lubility in al- 



lt has a red colour, and an extremely bitter taste. Water cohol. 



throws clown from it a copious precipitate of a fine red slightly 



inclining to rose-colour. The alcoholic solution, exposed 



to the air in an open vessel, crystallizes in a needly form like 



a salt. 



The alcoholic solution precipitated by water still retains a Tincture precl- 

 portion of this substance, which continues to give it a rose- P ltated by wa* 

 colour inclining to deep orange [nacarat], and a perceptibly 

 bitter taste. It deposits this in scales of a brown red by spon- 

 taneous evaporation. 



That principle of the cinchona, which is insoluble in alco- Principle inso- 

 hoi, being dissolved in water, filtered, and left to spontaneous j u bl ein ako- 

 evaporation in a warm place, thickens like a kind of sirup, 

 and crystallizes in laminae, sometimes hexaedral, at others Yields a sak. 

 rhoniboidal, at others square, and slightly tinged with a red- 

 dish brown. A portion of a thick fluid always remains, which 

 never crystallizes completely, and which must be separated 

 by decantation. 



By repeated solution and crystallization this salt may be Which may be 

 obtained white and pure. Of its properties I shall speak purified. 

 hereafter. As to the matter that does not crystallize, but re- The remainder 

 mains in the form of a mother water, it exhibited all the mucilaginous, 

 characters of a mucilaginous matter, still retaining a small 

 portion of the salt I have just mentioned, which it is impossi- 

 ble to separate from it entirely by crystallization. 



Action of acids on the rcsiduums of cinchona exhausted by water. 



The barks in question, after being exhausted by water, Action of acid* 

 and even by alcohol, still yield something to acids. They all af:er w *ter, 

 act nearly in the same manner: that is to say, their effect is 

 confined to simple solution, without occasioning any per* 

 ceptibie change in the nature of the principles of the cin- 

 chona. 



I must observe however, that, if the bark have been reduced Dissolve the 



to fine powder, aud subjected to the repeated action of a part soluble in 



, alcohol, 



large 



