46 'Experiments upon the 



the same matter retained by water. The pftrtion not soluble 

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

 had no longer any taste or colour j it was abundantly dis- 

 solved in water, and its solution yielded, on spontaneous 

 evaporation, lamellous crystals slightly coloured with a salt, 

 which we shall afterwards describe. 



The seventh maceration of the same quantity of cinchona 

 still precipitating with gall-nuts, it was thought that cold 

 water had not dissolved the whole of the principle which 

 produced this effect : the refuse of this cinchona was there- 

 fore boiled, and we obtained a liquor which presented all 

 the characters of the infusion, except that it did not precipi- 

 tate the emetic solution ; probably because it was too much 

 diluted with water. 



This species of cinchona, therefore, is not the same as 

 that which has been examined above under the same name. 



Ninth Species. — Cinchona ojjicinalis. 



Eightv-four grammes of this bark, treated like the c?«- 

 chona pubescens, yielded a liquor less coloured and more 

 mucilaginous than the latter, although equally bitter. This 

 infusion slightly reddened the tincture of turnsole ; tried by 

 the re-agents it presented phseuomena similar to those of 

 cinchona puhescevs. 



All the waters of maceration, when evaporated, furnished 

 a deposit, the properties of which were so confounded 

 with that obtained from the cinchona puhescciis i)\z\.ii v;;\i 

 thought they might be mixed together; but the liquor 

 floatinc; above, containing the essential salt of cinchonas, 

 was submitted separately to evaporation and to the spon- 

 taneous crystallization : after having separated from it the 

 Colourins: matter by means of alcohol, it furnished crystals 

 after a few days. Here, therefore, arc two species of cin- 

 chona which do not precipitate glue, and which, conse- 

 quently, are deprived of the principle to which this effect 

 is owing in other kinds ; according to M. Scguin, they 

 would lie ranked among the be>t kinds. 



After several washings in cold water, the last washings 

 always precipitating by gall-nuts, the husks were treated by 



warBi 



