ON rEEDING HOESES. 33 



to the second, will in a great measure comprehend the answer 

 to the third. 



"Wtat constitutes Food ? We shall the better understand 

 this question, if we consider the wants and the requirements of 

 the animal. * 



The organism of the horse is of ' a most elaborate and com- 

 plex character. A variety of functions are performed within 

 its iaterior. One of the most important of these functions is 

 that of respiration ; upon the due performance of which the 

 natural temperature of the body mainly depends. Through 

 the medium of the lungs, oxygen is passed into the blood ; 

 and through the agency of the blood this element (oxygen) is 

 carried and diffused through the entire body of the animal. 

 The action of the oxygen is twofold : it purifies the blood in 

 the lungs, and by so doing renders this fluid in a fit state to 

 supply the waste which is produced within the animal, by what 

 is denomiaated the process of internal combustion. As the 

 blood, however, is imbibed by the various tissues in its transit 

 through the body, a portion of oxygen is again liberated ; the 

 direct action of which is to cause another series of effects. It 

 acts immediately upon the old, effete materials of this complex 

 apparatus ; new compounds are formed ; and it is during the 

 formation of these new compounds, that heat is generated. 

 Chemical action and heat are inseparable. It would appear, 

 in fact, as though the former expended itself, and became 

 ultimately resolved into the latter. 



In addition, however, to the production of heat, from the 

 action of oxygen upon the waste materials of the organism, 

 the same process goes on between the oxygen and certain 

 constituents of the food, which principally consist of carbon, 

 sugar, gum, starch, and fat ; and which either separately, or in 

 combiaation, are always to be found in the food of the horse. 



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