ON VARIOUS SPECIES OF CINCHONA. ]J3 



It is evident from what has been seen, that it is this Co- Thisa mean 

 loured, bitter substance, which, in the maceration of the cin- ^a^nd^- 

 chona in question, produces with reagents all the phenomena table matter, 

 mentioned above. This substance seems to be a medium, in 

 its nature and properties, between vegetable and animal sub- 

 stances. Probably it is the eilicacious principle in the cure of Probably the 



,. , i- 1 i i- .i • l c febrifuge prin- 



intermittent fevers. I he liquor separated from this substance ci lc> * 



was treated with alcohol, which took up the colouring mat- 

 ter; and this proved to be nothing but a portion of the same ( 

 substance, that the water had retained. The portion insolu- 

 ble in alcohol was of the consistence of a thick mucilage, and 

 had scarcely any taste or colour. It dissolved in large quan-Salt of bark, 

 tity in water; and the solution yielded by spontaneous evapo- 

 ration slightly coloured and lamellated crystals of a salt, 

 which will be farther noticed in the sequel. 



The same portion of cinchona, when it had been macerated 

 for the seventh time, still giving a precipitate with galls, I con- 

 ceived, that the cold water had been incapable of dissolving 

 the whole of the principle, by which this effect was produced. 

 In consequence I boiled the residuum of the cinchona, and Residuum de- 

 the liquor thus obtained exhibited the same phenomena as cocted. 

 the infusion, except that it did not precipitate the solution of 

 Urtarised antimony, probably because it was too much di- 

 luted with water. 



This bark therefore is not the same as species 1, though 

 they are both called by the same name. 



Spec. 9« Common bark, cinchona officinalis. 



Eighty-four grammes [1297 grs.] of this bark, treated Common bark 

 like the preceeding, afforded a paler coloured liquor, and of tfte sho ! JS * 

 more mucilaginous, though equally bitter. This infusion i ts action with 

 slightly reddened that of litmus. With other reagents it ex- ^agents. 

 hibited similar phenomena to the cinchona pubescens. 



All the liquors obtained by maceration when evaporated 

 afforded a sediment, the properties of which so much resem- 

 bled those of the same substance from the cinchona pubes- 

 cens, that I conceived they might be mixed together: but the 

 supernatant liquor, containing the salt essential to cinchona, 

 was evaporated separately, and set to crystallize by sponta- 



Vol. XIX. Feb. 1808. i neous 



