HISTORY OF GEINE. 73 



firmed Vauquelin's observations. In 1810, Berzel- 

 ius, the most acute chemist of the age, in experiment- 

 ing on the barks of various trees, noticed products 

 similar to the elm gum, particularly in pine bark, 

 Peruvian bark, and especially in the elm, whose 

 properties will be presently mentioned ; but he not 

 only gave these products no name, but pointed out 

 marked differences between them. The substance 

 found in pine, is allied to what is called pectic acid, 

 that in Peruvian bark approaches starch, while that 

 from the elm is only a variety of vegetable mucilage. 



In 1812, James Smithson, an English chemist, 

 gave to the Royal Society of London, an account 

 of his. experiments on elm gum, which he had receiv- 

 ed from the same place and person, who originally 

 sent the article to Klaproth. Smithson thought the 

 substance more allied to extractive matter, than to 

 resin, and noticed that it contained 20 per cent, of 

 potash. A similar substance obtained from the ex- 

 udation of an English elm, contained a larger per 

 centage of potash, but no trace of this new substance 

 was detected in elm sap. 



In 1813, Dr. Thomas Thomson, the Coryphaeus 

 of British chemists, experimented on this elm gum in 

 its several varieties, and embracing the prevalent 

 opinion of its distinct nature, not however, because 



