40 DISSERTATION ON THE 



they reside in greatest quantity in the leaves, 

 and least in the roots. 



Experiment the first, with the flowers, proves 

 the presence of a free acid, as is evinced 

 from the infusion of litmus forming a red co- 

 lour. The action of the sulphate of iron may 

 arise from some modification of the gallic 

 acid. Though it is stated, that the infusion of 

 galls formed a very slight precipitate, yet as 

 this efiect was not produced until several 

 hours had elapsed, and as I was imahle to 

 effect the same experiment a second time, 

 either with the flowers or any other part, by 

 means of the same re-agents, no satisfactory 

 conclusion can be deduced as to the presence 

 of cinchonin. The extractive matter was readi- 

 ly evinced, from the brownish precipitation 

 caused by the muriate of tin, and from the 

 precipitate induced by the nitrate of mercu- 

 ry : the extractive principle was also shown 

 by the muriate of barytes. Tlie turbidness 

 produced with the oxalate of ammonia was 

 conjectured to contain linie ; and as, in a 



