FEEDING OF ANIMALS. 



339 



of this. Cheese, which at first sight might appear an exception, is in 

 reality not so ; for those cheeses which bring the highest price are 

 always those which contain the most butter ; whilst butter itself is 

 always dearer than cheese. 



In conclusion, it must by no means be understood that we would in 

 any way depreciate the value of even a somewhat liberal amount of 

 nitrogen in food. We believe, however, that on the current views too 

 high a relative importance is attached to it ; and that it would conduce 

 to further progress in this most important field of inquiry if the pre- 

 vailing opinions on the subject were somewhat modified. 



It is to be borne in mind, that at the time these opinions 

 were put forward, now more than forty years ago, the views 

 expressed were directly contrary to all recognised authority 

 on the subject ; and that it is since that date that so much 

 evidence has been accumulated, as to the amounts of urea, 

 and of carbonic acid, given off under varied conditions as to 

 food and exercise. Still, from the facts already at command, Food con- 

 it was concluded that the increased demand for food resulting f^f^w 



. t . ° demanded 



from the exercise 01 muscular power was specially character- by labour. 

 ised by the requirement for an enhanced amount of the non- 

 nitrogenous constituents. 



Confirmatory evidence was, however, not long wanting. Further 

 Thus, in 1854, we selected two pigs as nearly as possible of trmls - 

 equal weight and character; to one was given, ad libitum, 

 lentil-meal (containing about 4 per cent of nitrogen), and to 

 the other, also ad libitum, barley-meal (containing less than 

 2 per cent). Each animal was kept in a frame, with arrange- 

 ments for collecting the fasces and urine separately, as already 

 described. After they had been kept for a certain time on 

 their respective foods, one comparative experiment was con- 

 ducted for three days, and later on another for ten days. The 

 weights of the animals were taken at the beginning and at the 

 end of each experiment ; and, besides other particulars, the 

 amounts of nitrogen consumed in the food, and of urea voided, 

 were determined. The results are summarised in the follow- 

 ing table : — 



TABLE 76. — Experiments at Kothamsted with Pigs. 

 June to August 1854. 



