114 ON VARIOUS SPECIES OF CINCHONA. 



neons evaporation, after the colouring matter had boon sepa- 

 rated by alcohol, and in a few days crystals were produced 

 from it. 



Thus we have two species of cinchona, which do not preci- 

 pitate isinglass, and which are consequently destitute of the 

 principle, that produces this effect in other species. Accord- 

 ing to Mr. Seguin they are to be classed among the best sorts. 



After several washings with cold water, as galls still occa- 

 sioned a precipitate, the residuum was treated with hot water, 

 which acquired a pretty deep colour. This was less bitter 

 than the liquor obtained by maceration, and still more muci- 

 laginous than the decoction of the cinchona pubescens. It 

 formed a precipitate with galls and nitrate of mercury, and 

 • turned green with sulphate of iron ; but neither tartarised 

 antimony nor isinglass occasioned any change it it. 



This species therefore is not the same with that examined 

 above by the name of gray, and called superfine. 



Spec. 10. Large-leaved bark, cinchona magnifolia. 



Lar^e-leavcd A hundred grammes of this bark in fine powder, macerated 

 tark - for twenty-four hours, yielded a solution that did not pass the 



filter easily. It was of a ruby red colour, little mucilaginous, 

 slightly bitter, and very decidedly astringent. 

 Its action with This infusion did not redden that of litmus: neither galls 

 nor tartarised antimony afforded any precipitate with it : with 

 solution of isinglass it gave a copious precipitate: sulphate of 

 iron gave it the green hue of oxide of chrome, which muri- 

 atic acid converted into a dirty green. With the infusions of 

 the eigbth and ninth species it gave a precipitate. 



The water in which it was steeped cold a second time did 

 not precipitate isinglass. 



The several waters in which it had been macerated were 

 evaporated to the consistence of an extract, and treated with 

 hot alcohol, which acquired from it a very fine colour. This 

 alcoholic solution diluted with water, and tested with the rea- 

 gents employed with the first water in which it had been 

 macerated, exhibited the same results. The matter there- 

 fore, that produced the effects above enumerated, is soluble in 

 alcohol. 



The 



