ON VARIOUS SPECIES OF CINCHONA. 0]5 



The benzoic acid is but little soluble in cold water, and is benzoic, 

 volatilized without being decomposed. 



The o-allic acid too is but little soluble in cold water, and gallic, 



o 



blackens solution of iron. 



It is analogous to the acetous acid in the solubility of its acetous, 

 combinations; but the acetous acid does not crystallize, and 

 is volatilized without alteration. , 



I say nothing of the camphoric, suberic, or succinic acids, and others, 

 for they bear no analogy to it. 



Let us then conclude, that this acid is really different from The kink acid 

 all those hitherto known, and give it the name of Jcznic acid, 

 from the word quinquina, ti&U becoming more ultimately 

 acquainted with its nature and combination, we can frame a 

 better. 



It is to this acid united with lime, according to the report combined with 



of Mr. Deschamps, that the physicians of Lyons ascribe the li 1 me :. s * id , to be 



r l J - . , the febrifuge 



febrifuge virtue of cinchona. They assert, that no intermit- substance. 



tent fever can resist two doses of this salt of thirty-six grains 

 each. 



If this assertion. were proved, we might pretty easily con- 

 ceive how a drachm of this salt cures an intermittent fever, 

 for this quantity is as much as can be obtained from at least 

 live or six ounces of common gray bark. 



I cannot directly contradict this result, announced by per- This question- 

 sons of credibility and well informed ; yet I think 1 have suf- a e » 

 ficient reason, to entertain some doubts of its accuracy. In f or different 

 the first place, before it can deserve complete confidence, it reasons. 

 must have been tried a great number of times, and with uni- 

 form success: for it too often happens, that effects are ascribed 

 to medicines, which in fact are owing entirely to nature. In 

 the art of physic, more than in any other branch of natural 

 philosophy, causes are so complicated, that it is difficult to 

 trace with certainty what belongs properly to each. 



On the other hand physicians have learned by long expe- 

 rience, that the infusions and extract of bark prepared after 

 the manner of la Garaye are far from producing equal ef- 

 fects in fever with the quantity of bark from which they are 

 prepared, if this were administered in its natural state : yet 

 these preparations contain the salt in question. 



It is known too, that spirituous tinctures of bark, in 



which 



