FOOD CONSUMED TO MANURE PRODUCED 147 



combustion of fuel : the undigested products of the 

 solid excrements represent the ashes, and the urine 

 represents the volatile products. When wood is 

 burned the nitrogen is converted into volatile products. 

 When food is digested and utilized by the body the di- 

 gestible nitrogen is mainly converted into urea, while 

 the undigestible nitrogen is voided in the dung. 



177. Composition of Solid and Liquid Excrements 

 Compared. — In composition the liquid excrements 

 differ from the solids in having a much larger amount 

 of nitrogen and less phosphoric acid. 55 



The nitrogen of the food consumed influences the 

 amount of water in the manure. As a rule, a highly 

 concentrated nitrogenous ration, produces a higher per 

 cent, of water in the manure than a well-balanced 

 ration. There is but little phosphoric acid in the 

 liquid excrements of horses and cows, while the urine 

 of sheep and swine contains appreciable amounts of 

 this element. 



The liquid manure is more constant both in compo- 

 sition and amount than the solid excrements. This 

 fact may be observed from the following table, which 

 gives the composition of the solid and liquid excre- 



