CONSTITUENTS OP ANIMALS 107 



greatest in young and lean animals, and diminishes 

 towards maturity, and especially during fattening. 

 The proportion of nitrogenous matter and ash tends 

 to increase from youth to maturity, but diminishes 

 during fattening. Fat forms in most cases the prin- 

 cipal solid ingredient of well-fed animals ; its pro- 

 portion increases very largely during fattening. 



The largest proportion of nitrogenous matter and of 

 ash are found in the ox, the smallest in the pig. The 

 difference in the proportion of ash is chiefly due to the 

 wide difference in the proportion of bone in these two 

 animals. Fat is found in greatest quantity in the pig, 

 and is least in the ox. 



The following table shows the quantity of nitrogen, 

 and of the principal ash constituents, in the fasted live 

 weight of the animals analysed at Rothamsted. For 

 convenience of comparison each animal is assumed to 

 weigh 1,000 lbs. The table also gives the nitrogen 

 and ash constituents in wool, milk, and eggs ; it thus 

 supplies information as to the loss which a farm will 

 sustain by the sale of animal produce. The composi- 

 tion of wool is quoted from German analyses. 



These figures show that the ox contains, in propor- 

 tion to its weight, a larger amount of nitrogen, and a 

 much larger amount of phosphoric acid and lime, than 

 either the sheep or pig. Of all the animals raised on 

 a farm the pig contains the least of all the important 

 ash constituents. 



The large amount of potash in unwashed wool is 

 very remarkable; a fleece must sometimes contain 

 more potash than the whole body of the shorn sheep. 

 The German analyses quoted in the table probably refei 

 to merino sheep. The fleeces of the four Hampshire 



