202 OF MANURE. 



botanist, attached to the Dutch embassy to China, 

 could scarcely find a single plant on the corn-fields 

 of the Chinese, except the corn itself.'^ 



The urine of horses contains less nitrogen and 

 phosphates than that of man. According to Four- 

 croy and Vauquelin it contains only five per cent, of 

 solid matter, and in that quantity only 0*7 of urea ; 

 whilst 100 parts of the urine of man contain more 

 than four times as much. 



The urine of a cow is particularly rich in salts of 

 potash ; but according to Rouelle and Brande, it is 

 almost destitute of salts of soda. The urine of 

 swine contains a large quantity of the phosphate of 

 magnesia and ammonia; and hence it is that concre- 

 tions of this salt are so frequently found in the 

 urinary bladders of these animals. 



It is evident, that if we place the solid or liquid 

 excrements of man or the liquid excrements of 

 animals on our land, in equal proportion to the 

 quantity of nitrogen removed from it in the form of 

 plants, the sum of this element in the soil must 

 increase every year; for to the quantity which we 

 thus supply, another portion is added from the 

 atmosphere. The nitrogen which we export as corn 

 and cattle, and which is thus absorbed by large 

 towns, serves only to benefit other farms, if we do 

 not replace it. A farm which possesses no pastures, , 

 and not fields sufficient for the cultivation of fodder, 

 requires manure containing nitrogen to be imported 

 from elsewhere, if it is desired to produce a full 

 crop. In large farms, the annual expenditure of 

 nitrogen is completely replaced by means of the 

 pastures. 



The only absolute loss of nitrogen, therefore, is 

 limited to the quantity which man carries with him 

 to his grave ; but this at the utmost cannot amount 

 to more than 3 lbs. for every individual, and is being 

 collected during his whole life. Nor is this quantity 



* Ingenhouss on the Nutrition of Plants, page 129 (German edition). 



