CHAPTER XII 



THE FEEDING EXPERIMENTS 



I. Relative Value of Nitrogenous and Non-nitrogenous Constituents of Food. 

 II. Relation of Nitrogenous Food to Work. 



III. The Source of Fat in the Animal Body. 



IV. Relation of Food Consumed to Live Weight Increase. 



V. The Composition of Oxen, Sheep, and Pigs, and of their Increase during 



Fattening. 

 VI. The Manure Value of Foods. 

 VII. Miscellaneous Feeding Experiments. 

 References. 



I, — Relative Value of Nitrogenous and Non-nitrogenous 

 Constituents of Food. 



At the date of the inception of the Rothamsted Experiments 

 even less was known about the laws of the nutrition of animals 

 than of crops, though the question had excited more interest on 

 the Continent than in England. Here attention had been in the 

 main concentrated upon the animal ; it had been the object of 

 breeders and graziers to develop races of stock that would give 

 the least waste and the largest proportion of useful meat to live 

 weight. To this end early maturity had also been successfully 

 sought, thus economising the food used merely in keeping the 

 animal alive without, increasing its weight. On the Continent, 

 however, even in the eighteenth centmy, attention had l^een 

 rather directed to the character of the food, and especially to 

 obtaining a measure of the comparative value of different foods, 

 with the view of ascertaining how far one could replace 

 another. 



As an example of what was going forward, Thaer's " hay 



