86 HISTORY OF GEINE. 



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, and the 

 munificent founder of the " Institute " which bears his name, 

 gave to the Royal Society of London an account of his ex- 

 periments on elm gum, which he had received 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 

 exudation 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 Coryphseus of British 

 chemists, experimented on this elm gum in its several varie- 

 ties, and embracing the prevalent opinion of its distinct 

 nature, not, however, because prevalent, but from his own 

 researches, erected it into a distinct vegetable principle, 

 under the name of ulmin, from ulmus, the Latin for elm. 

 He confounded under this name the several products noticed 

 by Berzelius, in bark ; and hence, thinks there are several 

 varieties of this substance, though Berzelius does not counte- 

 nance this idea. Thomson was the first who ever procured 

 ulmin pure, but this was not the elm mucilage, but the 

 extractive matter, and he thus gave the name ulmin to the 

 apotheme of Berzelius. 



Not long after this name had become the property of 

 chemists, Braconnot found, in experimenting on the action 

 of alkali on woody fibre, that a substance was produced 

 analogous to elm gum and the varieties of ulmin, and, in 

 1830, BouUay noticed that ulmin had acid properties, and 

 gave to it the name of ulmic acid. 



