HISTORY OF GEINE. 75 



Hence it was found in a vast variety of substances, 

 and even cast-iron was found to contain about 2 per 

 cent, of a compound, so analogous to ulmin, that it 

 is so called. But above all, it was found to be the 

 great product of spontaneous decay of plants, and 

 hence existed abundantly in peat and soil. Spren- 

 gel, directing his attention particularly to its existence 

 in soil, before that form of it was universally allowed 

 to be identical with ulmin and ulmic acid, bestowed 

 on it the name of humic acid, from the Latin, humus, 

 or mould. Sprengel investigated minutely the vari- 

 ous salts of this substance, and first endeavored to 

 determine its chemical constituents. 



Boullay soon followed in the same path of in- 

 vestigation, and with almost similar results. There 

 were marked differences between all the forms, yet 

 observed, that is, between elm gum of Palermo, the 

 product of bark, the artificial ulmin of Braconnot, 

 and that of soil. A multitude of different, but anal- 

 ogous substances were confounded under a common 

 name, which began to be applied to the matter of 

 all vegetables, which after having been heated with 

 alcohol and water, yielded to alkali a solution, pre- 

 cipitable in brown flocks, by an acid. Under these 

 circumstances, Berzelius objected to the term alto- 

 gether, and if there is a substance to which he would 



