94 THEORY OF FEEDING. 



Bunge states that " the food must be more abundant in 

 carbo-hydrates in proportion to the work performed by the 

 muscles, and more abundant in fat according to the lowering 

 of the surrounding temperature." From what has already 

 been said, we know that both work and the maintenance of 

 the internal temperature demand the expenditure of energy. 

 The nitrogenous matter of food can be utilised by the system 

 to some extent for supporting the internal temperature and 

 for forming fat, as it contains the necessary carbon and 

 hydrogen to become oxidised. Its fat-forming and heat- 

 developing power is, however, much more feeble among 

 vegetable feeders, like the horse, than among the carnivora, 

 whose normal amount of fat and internal temperature can be 

 sustained on a diet of lean meat, which consists practically of 

 nitrogenous matter. Starch and sugar, as we have seen, are 

 capable of forming fat in the system, but not so readily as 

 food-fat, which can become absorbed and deposited in the 

 tissues without having to undergo any chemical modification. 

 Vegetable feeders, like the horse, have far less power of 

 absorbing fat from food than carnivora, which in a state of 

 nature consume little or no starch or sugar. 



Professor Ugolino Mosso has shown by experiments he 

 made in the University of Genoa on fasting animals, that 

 sugar is far more efficacious than starch or albumen in raising 

 the internal temperature, when, owing to deprivation of food, 

 it has fallen below its normal standard. This good effect of 

 sugar is particularly well marked in cases of extreme heat 

 depression from long fasting, and is in accordance with the 

 fact that energy is much more readily supplied to the body 

 by sugar than by the other two substances. The amount of 

 sugar given with the object in question, varied from .1 to .4 

 per cent, of the animal's weight, namely, I to 4 Ib. for a 

 horse weighing 1,000 Ib. 



Lawes and Gilbert have proved by experiment, that the 



