■WHITE WILLOW, cVc. *:? J, 



The deposit caused by antiraonial taitritc of potash is so, TTabittules of 

 abundant, that there is reason to believe all the metallic sail *'".*^ 'Iffoction 



with voiious 



is decomposed. The supernatant liquor is without color.r : agents. 

 hydrosulphuret of pot-ash, added in whatever propoition, 

 causes no red precipitate. 



The liquor., separated from the deposit, and filtered, no lun- 

 ger possesses its bitter nor acerb flavor ; it reddens tincture 

 of turnsole more deeply than the solution of tartar emetic, it. 

 still gives a precipitate with sulphate of iron, but of a green 

 colour instead of blue; and is not affected with sohitum of glue. 



From these experiments, it may be concluded, that the ex- 

 tractive colouring, resinous, and tannin matter is what causes 

 the acerb and bitter flavor, and combines with the oxide of an-' 

 timony ; and that the substance which remains in- the liquor, 

 and gives a green colour with sulphate of iron, is a particular 

 acid. 



M. Vauquelin attributes this effect in quinquina, rhubarb, 

 and root of calaguala (the latter of whicli he has just exa- 

 mined), to the resin contained in those substances : but, I 

 think, that the green colour with sulphate of iron, may be at- 

 tributed to a modification of the gallic acid. 



This acid, so modified, exists in a number of vegetables, 

 which contain tannin, as is proved in my .'•esearches on this 

 substance: it is found in the catecher, the arnica, and many 

 other vegetables, ranked among tanning matters. 



The extract obtained by evaporating the dccocfmn of honnc! ri'.tinrf of dmv 

 root, is so analogous in its characteristics, to those of quin- 

 quina, that much experience is necessary to enable us to dis.- 

 tinguish one from the other. 



• If lime be throv/n into a concentrated solution of this ex- 

 tract, a disengagement of ammonia takes. 



Alcohol ako acts upon this root, and received from it a :^'^'?''*^^"V . 



V _ ' tincture oi 



brownish tint, but not quite so deep as that which it acquire*, bennet root. 

 from good quinquina. Its taste is bitter and acrid, water (iis- 

 turbs its transparency, and it reddens the tincture of turnsole. 



Lime water causes a more abundant precipitation than 

 with the alcoholic tincture of quinquina, a circumstance wliich 

 proves tills root to contain more tannin and gallic acid, but a 

 little less resin than the true quinquina. 



The solution of tartar emetic, is equally decomposed by this 

 tincture. Sulpliate of iron also gives fiom it a fiae black pre- 

 cipitate' 



