SOO now CROPS FEED. 



puric acid is subjected to the action of strong acids or 

 ferments. 



Hampe, therefore, experimented with glycocoll, and 

 from his trials formed tlie opinion that this body is di- 

 rectly nutritive. In fact, he obtained with it a crop equal 

 to that yielded by ammonia-salts. 



Knop, who made, in 1857, an unsuccessful experiment 

 with hippuric acid, found, in 186G, that glycocoll is as- 

 similated {Chem. Centndblatt, 1866, p. 774). 



In 1868, Wagner ex])erimented anew with hippuric 

 acid and glycocoll. His results confirm those of Hampe. 

 Wagner, however, deems it probable that hippuric acid 

 enters the plant as such, and is decomposed within it into 

 benzoic acid and glycocoll ( Vs. St., XI., p. 294). 



Wagner found, also, that kreatin is assimilated by 

 vegetation. 



The grand result of these researches is, that the nitrog- 

 enous (amide-like) acids and bases which are thrown off 

 in the urinary excretions of animals need not revei't, by 

 decay or putrefaction, to inorganic bodies (ammonia or 

 nitric acid), in order to nourish vegetation, but are either 

 immediately, or after undergoing a slight and easy altera- 

 tion, taken up and assimilated by growing plants. 



As a practical result, these facts show that it is not 

 necessary that urine should be fermented before using it 

 as a fertilizer. 



COMPARATIVE NUTRITIVE VALUE OF AMMONIA-SALTS AND 



NITRATES. 



The evidence that both ammonia and nitric acid are ca- 

 pable of supplying nitrogen to plants has beeii set forth. 

 It has been sliown further that nitric acid alone can per- 

 fectly satisfy the wants of vegetation as regards the ele- 

 ment nitrogen. In respect to ammonia, the case has not 



