COMPOSITION OF MANUKE. 135 



of tissue being in this case equivalent to the quantities 

 yielded by the degradation of tissue. In cases where 

 the animal is increasing in size, is producing young, or 

 furnishing wool or milk, the amount of nitrogen and ash 

 constituents in the manure will be leus than that in the 

 food in direct proportion to the quantity of these sub- 

 stances which has been converted into animal produce. 

 The manure from animals of the latter description will 

 thus be poorer than that obtained from the former class, 

 supposing the same food to be given to each. 



The proportion of the nitrogen in the food which will 

 appear in the solid excrement is determined by the diges- 

 tion co-efficient of the nitrogenous constituents. Thus 78 

 has been already given as the digestion co-efficient of the 

 nitrogenous matter of barley meal when consumed by a 

 pig; it follows that in this case for 100 of nitrogen con- 

 sumed 22 will be voided in the solid excrement, and 78 

 pass into the blood. Ifc has been already stated that 

 500 Ibs. of barley meal, containing about 531bs. of 

 nitrogenous substance, will in the case of a fattening pig 

 produce 100 Ibs. of animal increase, containing 7*8 Ibs. of 

 albuminoids. It follows from these data, that for 100 Ibs. 

 of nitrogen consumed, 14*7 are stored up as carcase, 22 

 appear in the solid excrement, and 63*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 calcuktion in the case of the fattening 

 ox, sheep, and pig receiving the diets mentioned on page 

 124. The relation of food to manure in the case of 

 milking cows is calculated from recent Rothamsted 



