COMrOSITION OF MANURE 213 



producing young, or furnishing wool or milk, the 

 amount of nitrogen and ash constituents in the 

 manure will be less than that in the food in direct 

 proportion to the quantity of these substances which 

 has been converted into animal increase. The manure 

 from animals of the latter description will thus be 

 poorer than that obtained from the former class, sup- 

 posing the same food to be given to each. Ordinary 

 labour does not increase the quantity of nitrogen and 

 ash constituents voided. 



The proportion of the nitrogen in the food which 

 will appear in the solid excrement is determined by 

 the digestion coefficient of the nitrogenous constitu- 

 ents. Thus 79 has been already given as the diges- 

 tion coefficient of the nitrogenous matter of barley 

 meal when consumed by a pig. It follows that, in this 

 case, for 100 of nitrogen consumed, 21 will be voided 

 in the solid excrement and 79 pass into the blood. It 

 has been already stated that 500 lbs. of barley meal, 

 containing about 53 lbs. of nitrogenous substance, will, 

 in the case of a fattening pig, produce 100 lbs. of 

 animal increase, containing 7'8 lbs. of albuminoids. It 

 follows from these data, that for 100 lbs. of nitrogen 

 consumed, 14-7 are stored up as carcase, 21 appear in 

 the solid excrement, and 64*3 as urea, &c., in the 

 urine. In the same way, by deducting the ash con- 

 stituents stored up from those present in the food, we 

 can arrive at the quantity of ash constituents voided 

 in the manure. The following table shows the results 

 obtained by this mode of calculation in the case of the 

 fattening ox, sheep, and pig receiving the diets men- 

 tioned on p. 193. The relation of food to manure in 

 the case of milking cows is calculated from Eothamsted 



