216 



THE CHBMISTRY OF THE FARM 



exceed that contained in the urine. On the other 

 hand, corn and cake yield a large excess of nitrogen in 

 the urine. 



The ash constituents are very differently distributed 

 in the solid excrement and urine ; in the former is 

 generally found nearly all the phosphoric acid, and 

 the greater part of the lime and magnesia, while the 

 urine contains the greater part of the potash. Horse 

 urine is an exception to the above rule, as it contains 

 a rather notable amount of lime. "When animals 

 receive food containing a considerable amount of alkali 

 phosphates and but little lime, phosphoric acid will 

 appear in the urine. Pigs fed on potatoes, peas, and 

 milk yielded over 50 per cent, of the phosphoric acid 

 in their urine. With sheep and horses, and probably 

 more or less with other animals, a part of the potash is 

 excreted in the perspiration. 



The following table shows the distribution of nitro- 

 gen, phosphoric acid and potash in the milk, solid 

 excrement, and urine of a cow. The experiment 



