PEODUCTION VALUE OF FOODS 



125 



the carbon in the increase of the nitrogenous tissues 



being first deducted. This mode of work involves the 



use of a respiration chamber, and is far more exact 



than any calculation from the alterations in live 



weight. Kellner's results are shown in the following 



table : — 



HEAT VALUES OF DIGESTED POODS AND OF THE 

 INCREASE OBTAINED IN A FATTENING OX. 



The table starts with the heat values of the digested 

 foods, which have been arrived at by the calculations 

 shown in the table on p. 120. Before these digested 

 foods can be utilised for the production of fatty or 

 nitrogenous tissue, a part is consumed to provide the 

 energy required for the digestion of similar food daily 

 received by the animal ; a part is also consumed during 

 the chemical and mechanical processes involved in 

 the production of tissue. The whole of the food thus 



