FOOD 113 



under the influence of oxidation are resolved into simple 

 groups of atoms, and the chemical force which linked these 

 atoms together while in their complex condition, is now set 

 free to be utilized as kinetic energy for the external work of 

 the body. This energy can be stored up in the system until 

 required, and when it is exhausted a period of rest is 

 needed in order that fresh energy may be accumulated. 



This question no doubt invades the field of physiology, 

 but is dealt with here to avoid the question of muscular 

 energy being regarded as a purely physical one, due to the 

 production of heat in the body. It is something far more 

 complex, we only know the beginning and end, viz., that 

 food is supplied and work results, but the processes by 

 which these are linked together are quite unknown. 



THE AMOUNT OP POOD REQUIRED DAILY. 



The loss in the animal body is of two kinds — (1) That 

 dependent on the internal work of the body, such as the 

 action of the heart, movement of the bowels, heat, respira- 

 tion, etc. ; (2) The loss from muscular and other move- 

 ments. 



Two diets are therefore required, the first to allow of a 

 perfectly balanced condition of the body, restoring the loss 

 occasioned by the internal work, so that the body-weight 

 shall remain unchanged ; the second to restore the waste 

 of muscular and increased respiratory activity resulting 

 from external work. The first is called the essential or 

 subsistence diet; the second the variable diet. 



Subsistence Diet. 



Horses.— A large number of experiments have been made 

 to ascertain the smallest amount of food a horse in a state 

 of rest requires, in order to prevent loss of body-weight. 

 In these calculations observers have not adopted a uniform 

 system of dealing with the question of cellulose, and if this 

 is included by some and excluded by others, a discrepancy 

 exists in the amount of carbo-hydrate required for the 



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