46 DISSERTATION ON THE 



sulphate of iron, and the precipitation induced 

 by gelatin, manifested the existence of tannin 

 and modified gallic acid in the leaves, while, 

 with the same re-agents, the root was ascertain- 

 ed to be nearly destitute of it. The oxalate of 

 ammonia, by the immediate and copious preci- 

 pitate which it caused, while it convinced us 

 that the leaves also possessed lime, in no small 

 degree, it rendered it no less certain, in our ex- 

 periments with the root, that from this portion 

 of the plant, this ingredient was not to be ob- 

 tained, at least in any sensible quantity. By 

 the other tests it is also proved, that the vir- 

 tues of the root, while they differ in quality, 

 are also less in quantity. 



I have stated the results of the simple de- 

 coction, and of the simple infusion. With 

 the view of ascertaining more satisfactorily 

 the properties of the plant, as taken up by this 

 last preparation, I subjected the infusion itself 

 to the process of distillation. After the pro- 

 cess had been continued until nearly one half 

 had come over, upon examination, nothing but 



