' CONTENTS 



ments, 227; Relative efficiency of different phosphorus 

 compounds, 228. Functions of Protein: Proteins as 

 tissue-formers, 229; Protein as a source of fats, 230; 

 Protein as a source of energy, 231. Functions of Car- 

 bohydrates: Carbohydrates the chief source of energy, 

 232; Proportion of ration used as fuel, 233; Fats from 

 carbohydrates, 234. Functions of Ove Fats and Oih: 

 Fats and carbohydrates similar in function, 235. Food 

 as a Source of Energy: Work performed by the animal 

 organism, 236; Work requires the expenditure of energy, 

 237; The animal organism does not originate energy, 

 238; The nature of energy, 239; Transformations of 

 energy though the use of machinery, 240; The horse a 

 machine, 241; Measurement of energy, 242; Determina- 

 tion of energy imits in feeding-stuffs, 243; MetaboUzable 

 energy, 244; Loss of food energy in feces, 245; Loss of 

 food energy in urine, 246; Loss of food energy in gases, 

 247; Recent determinations of metabolizable energy, 

 248; Distribution of losses of food energy, 249; Influence 

 of size of ration on losses of methane, 250; Influence 

 of size of ration on losses in the undigested residue, 251 ; 

 Influence of individuahty on energy losses, 252; 

 Estimates of metabolizable energy on the basis of 

 digestible organic matter, 253; Comparison of metabohz- 

 able energy in coarse fodders and grains, 254; Net 

 energy, 255; Work of mastication, 256; Difference in 

 total energy use with different rations, 257; The work of 

 digestion, 258; Total energy expended in feed consump- 

 tion, 259; Calculation of net energy value, 260; Net 

 energy of various feeds, 261; Computing net energy 

 values of feeding-stuffs, 262; Estimation of produo- 

 tion values proposed by Armsby, 263. Energy Rekir 

 tions. — Heat Regulation: Relation of protein to 

 muscular activity, 264; Energy chiefly from carbohy- 

 drates and f-ats, 265; Heat regulation, 266; Animal heat a 

 secondary or waste product, 267; The critical tempera- 

 ture, 268. The NuMtive Inter-Rdation of the Food Com- 

 pounds and the Need of Combining These in the Ration: 

 Protein physiologically necessary, 269; Carbohydrates 



