50 ORIGIN AND ACTION OF HUMUS. 



All superabundant nitrogen is eliminated from 

 the body, as a liquid excrement, through the uri- 

 nary passages; all solid substances, incapable of 

 further transformation, pass out by the intestinal 

 canal, and all gaseous matters by the lungs. 



We should not permit ourselves to be withheld, 

 by the idea of a vital principle, from considering, 

 in a chemical point of view, the process of the trans- 

 formation of the food, and its assimilation by the 

 various organs. This is the more necessary, as the 

 views, hitherto held, have produced no results, and 

 are quite incapable of useful application. 



Is it truly vitality, which generates sugar in the 

 germ for the nutrition of young plants, or which 

 gives to the stomach the power to dissolve, and to 

 prepare for assimilation all the matter introduced 

 into it? A decoction of malt possesses as little 

 power to reproduce itself, as the stomach of a dead 

 calf; both are, unquestionably, destitute of life. 

 But when amylin or starch is introduced into a 

 decoction of malt, it changes, first into a gummy- 

 like matter, and lastly into sugar. Hard-boiled 

 albumen and muscular fibre can be dissolved in a 

 decoction of a calf's stomach, to which a few drops 

 of muriatic acid have been added, precisely as in 

 the stomach itself. * (Schwann, Schulz.) 



The power, therefore, to effect transformations, 



* This remarkable action has been completely confirmed in this 

 laboratory (Giessen), by Dr. Vogel, a highly distinguished young phy- 

 siologist. 



