various species of Cinchona. ' 145 



In fact, oxalic acid forms a salt insoluble with lime, and, 

 besides, decomposes the combination of this earth with the 

 acid of cinchona. 



The clfiic and tartareous acids also form an Insoluble 

 combination with lime, and decompose the acetate of lead. 



The malic acid does not crystallize, and precipitates the 

 acetate of lead. 



The benzoic acid is not very soluble in cold water, and 

 volatilizes without decomposition. 



The gallic acid is also very little soluble in cold water, and 

 blackens the solution of iron. 



It has some similarity to the acetous acid by the solubility 

 of its combinations; but the acetous acid does not crystal- 

 lize, and volatilizes without undergoing any alteration. 



I shall not mention the camphoric, suberic, and succinic 

 acids, because they have no analogy with the one in ques- 

 tion. 



We must conclude, therefore, that this acid is truly dif- 

 ferent from all those which are known ; and we ought to 

 give the name of kinic acid to it, from the word cinchona, 

 until we are able to give it a better. 



It is to this acid, united with lime, that the physicians of 

 Lyons, according to M. Deschamps, have attiibuied the fe- 

 brifutre virtues of cinchona; thev n)aintain that no inter- 

 mittent fever can resist two doses of this salt, of 36 grams 

 each. 



If this assertion were proved, we could easily conceive how 

 a drachm of this salt could cure an interiTiittent fever, be- 

 cause this quantity represents at least five or six ounces of 

 common gray cinchona. 



I would not directly deny the result thus announced by 

 learned and respectable men; but I think myself warranted 

 in starling some doubts on the subject. 'In the first place, 

 before it deserves implicit confidence, the experiment ought 

 to be repeated a great number of limes, and the success ought 

 to be constant ; for it often happens that efTects are attri- 

 buted to medicines, which belong to nature alone. In me- 

 dicine, more than in any other branch of philosophy, it is 

 K 2 difficult 



