56 SCIENTIFIC FEEDING OF ANIMALS 



food, which brings heat and energy, it is clear that 

 body tissue equal in quantity to the heat which is 

 liberated from the food in the body will be saved. 

 Various investigations with carnivorous animals 

 and rabbits have confirmed this. 



In order to prevent a loss of ioo gr. of body fat it 

 is necessary, according to calculations based upon 

 the heat values (p. 48), to give 235 gr. cane sugar. 

 An experiment on a fasting dog which received only 

 cane sugar showed that 234 gr. of that substance 

 can take the place of 100 gr. of body fat. Other 

 experiments with lean or extracted flesh, starch, 

 grape sugar, etc., lead to the same conclusion. This 

 proves accordingly that the several nutrients can 

 mutually replace one another in proportion to the 

 amount of heat which is set free when they de- 

 compose in the body. This law, however, only 

 holds good where the total quantity of food con- 

 sumed does not yield more heat than the animal 

 gives off during starvation, that is, it applies only 

 to a maintenance ration. In the fasting animal 

 part of the energy arising from the decomposition 

 of the nutrients does not immediately take the form 

 of heat, but is first utilised for work and afterwards 

 manifests itself as heat. With carnivorous animals it 

 has been possible to determine that portion of the 

 energy of the food which serves for work, and it was 

 thereby shown that only a portion of this — never 

 the whole — undergoes conversion in the animal 



