CHEMISTRY OF THE FEEDING OF ANIMALS. 



191 



Table V. — Average Annual Produce of Wheat, and estimated Yield 

 of Carbon per Acre, over 12 years. 



Manures per Acre per Annum. 



Unmanured 



Mineral manure alone 



Mineral manure and 400 lbs. 

 14 tons farm-vard manure. .. 



ammonia salts. 



Average Annual Produce per Acre. 



Dressed 

 Corn. 



Bushels 

 l.H 



m 



35i 



Total 

 Corn. 



lbs. 

 9G4 

 1157 

 2275 

 2232 



Straw, i Carbo 



lbs. 

 1002 

 1897 

 4212 

 3869 



lbs. 



1002 



1234 



2G25 



2467 



(the latter containing a large amount of nitrogen) the yield of car- 

 bon was greater than where a large amount of that substance was 

 supplied by means of farm-yard manure. This carbon must have 

 been derived from the atmosphere. In several experiments in this 

 field last year, from l^ to 1| tons of carbon per acre were re- 

 moved in the crop, without any being supplied in manure ; but in 

 these cases large quantities of nitrogen were supplied. 



The quantity of carbonic acid required to yield ig tons of car- 

 bon to the crop is about as much as would be given off into the 

 atmosphere in a ^'■ear by twenty-two individuals of a mixed popu- 

 lation of both sexes and all ages, and it will be seen that it is 

 under the influence of ammoniacal or nitrogenous manure that this 

 large amount of carbon has been fixed in the plant from the car- 

 bonic acid of the atmosphere. 



The results given in Table III. showed how small was the pro- 

 portion of the nitrogen consumed by an animal in its food that 

 was stored up in its increase, and sent to market as meat. If 

 there were none of the nitrogen of the food lost in the various ex- 

 halations from the body the whole of that not stored up in increase 

 would be found in the manure. But the investigations of our- 

 selves and others show that a certain portion of the nitrogen is so 

 lost. Our own experiments to determine the limit of this loss, 

 and the circumstances under which it is greater or less, were com- 

 menced as far back as 1847, and have been resumed occasionally 

 from that time to the present ; and during the last few years we 

 have collected a great deal of experimental data on the subject ; 

 but as the whole of the analytical work is not yet concluded, I do 

 not feel that I am in a position to give any numerical statement of 

 the results obtained. It may, however, be stated as beyond a 

 doubt, that by far the larger portion of the nitrogen consumed in 

 food is rejected by the animals in their liquid and solid voidings ; 



