88 HISTORY OF GEINE. 



is treated with alcohol. The tincture is evaporated dry, and 

 the extract treated with water, which dissolves a brown ex- 

 tractive matter, leaves an insoluble residue, which being 

 treated with ether, leaves a small quantity of a brownish 

 matter, analogous to the extractive of chemists, or the 

 brown apotheme of Berzelius. The sap of elm contains 

 acetate and carbonate of potash. Here, then, are all the 

 elements of elm gum, as examined by Vauquelin, Klaproth, 

 Smithson, Thomson. Not only the elm, but other trees, 

 under diseased action, exude these matters, and under the 

 influence of air, and the potash, the diseased exudation from 

 the elm bark is changed to true ulmic acid, which unites 

 with the potash, and both with the mucilage. The mucilage 

 may, by processes not here necessary to be detailed, be pro- 

 cured pure, as a hard, opaque, colorless, insipid, and inodor- 

 ous gum. It moistens easily, swells in water, becoming a 

 semi-transparent mucilage. It is insoluble in alkali, affords 

 no ammonia by dry distillation. Boiled with alkaline lye, 

 it affords a clear mucilaginous liquor, which browns by being 

 exposed to air. If this lye or solution is exactly neutralized 

 by acetic acid, lime water and salts of lime produce no pre- 

 cipitate in it, and it is only rendered slightly turbid by sul- 

 phuric, nitric and muriatic acids. It is not precipitated by 

 acetate of lead, nor by sulphate of iron. With alcohol and 

 sub-acetate of lead it affords a mucilaginous precipitate. It 

 is evident that it differs widely from artificial ulmin, and 

 from ulmin of soil, and, therefore, when Berzelius turned his 

 attention to' that, having advised the abandonment of the 

 name ulmin, as inapplicable to any one substance, he 

 bestowed on the ulmin of soil the name of geine, from the 

 Greek (/e, earth. If a distinction is therefore to be main- 

 tained, it may be said that ulmin is the product of life; 

 geine, of decay. 



