62 



GN THE BARK OF 



cipitate, whose colour may be rendered more intense, by 

 the addition oi" a few drops of oxigenated muriatic acid. 



^lUliJ 



Tre'iumtition. The experiments above reported on willow bark and 



lhe\^i!lo\v, bennet root, prove tlse identity of these substances with quin- 

 bark, and ben- . . 



m-t root, re- quina of the best quality. 



qii'fi- A simple comparison will determine our ideas on this sub- 



ject. 



It would be nugatory here to detail the comparative experi- 

 ments made upon quinquina and the barks sold under that 

 Dame ; the latter are so far from possessing its characteristic 

 and chemical properties, that too much care cannot be taken 

 to avoid them ; and I am at a loss to conceive why means 

 have not been adopted to prevent their sale as medicinal ar- 

 ticles. 

 Stratraient of '^^'^ following are the most striking phenomena which I 

 th« tacts oh- have observed in quinquina : 

 served i:i quiii- . . . , • -, ,,■,-,■ 



The decoction precipitates glue, is decomposed by alcuhne 



EiliiU. 



It has a little 



carbonates, renders the emetic solution turbid, and gives a 

 green precipitate with sulphate of iron. 



Decoctions of white willow bark, and of bennet root, pre- 

 sent similar phenomena, except that bennet root yields a blue 

 precipitate with sulphate of iron. 



The alcoholic tincture of quinquina, ditTers from those of 

 1\'il!ow and bennet root, only in possessing a deeper colour. 



Aqueous and dry extract of quinquina seems to me to pre- 

 sent similar characters with willow and bennet : that of wil- 

 low, however, attracts less moisture from the air. 



It is evi<]ent, therefore, that the only difl'erence consists in 



than. a triple more of resin, which varies according to the species 



before exa-^'' of quinquina, and llie method of making the extract. What 



mined. is now called in commerce, gooti quinquina, differs but very 



little from these two substances, paiticularlv bennet root. 



We may conclude, that these indigenous vegetables con- 

 tain, like quinquina, chieily tannin, a colouring extractive 

 niatter, resin, and an acid, which I suppose to be a modiiicd 

 gallic acid in willow, quinquina, and the other substances 

 above-mentioned, whilst it is gallic atiu in the root of tlm 

 herb bennet. 

 Thi« cornrnri- ^'^ '"'^y ^^ observed, by the foregoing exposition, that my 

 sou IS not a re o')ject has iiot been to enter into a regular analysis of these 



r-;lar ait<i".v.sis. 



■^ ' t\vo 



