EUPATORIUM PERFOLIATUM. 43 



and extract is also proved. From the sixth 

 experiment we obtain the same results as in 

 the preceding. The ochre colour which the 

 solution acquired by the carbonate of potash 

 was owing to extractive. Little need be said 

 of experiment the seventh ; it showed the pre- 

 sence of gum united to extract and tannin. 



From experiment the eighth a principle was 

 obtained which was soluble in alcohol and in 

 water. VAuauELiA, in his examination of 

 the Peruvian bark, also discovered a similar 

 material, which he is inclined to believe a new 

 principle ; he calls it a resiniform matter.* 



* From the re-agents employed in this experiment, a con- 

 clusion might perhaps be drawn, that this principle approach- 

 ed to the nature of that denominated by Dr. Thomson, in his 

 system of chemistry, artificial tannin, or the second species 

 of bitter principle. Mr. Chenevix procured this principle 

 from a filtered preparation of digested unburned coffee, in 

 water; and, though I had not an opportunity of making use 

 of all the re-agents that he employed in his examination, yet 

 it seems to be highly probable that the eupatoriura contains 

 a material very analagous to that found in coffee. From 

 the experiments of Lagrange, it appears, that a substance 



