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CHAPTER V. 



On Watering Horses. 



THE blood being the source from which the different 

 tissues obtain materials for repair and development, 

 and the vehicle which conveys away the effete pro- 

 ducts resulting from the constant waste that goes on in 

 the animal economy, the whole question of nutrition 

 depends on supplying the system with materials suit- 

 able for preserving that fluid in its normal and healthy 

 condition. 



The proportion of water in the blood varies from 

 700 to 790 parts in 1,000. Its presence is essential to 

 the performance of the various functions. If its supply 

 be curtailed, the secretions' that are indispensable to 

 the process of digestion are checked either wholly or 

 in part, because the glands are unable to obtain a 

 sufficiency of water from the blood. If, on the con- 

 trary, more water be drank than is needed for the 

 requirements of the system, the excess is quickly 

 eliminated by the kidneys, skin, and lungs, without 

 doing any harm. We may conclude, therefore, that a full 

 supply of water, given a short time before feeding, is 

 essential for the proper digestion of food. 



The stomach is furnished with a vast number of 

 blood vessels, whose office is to absorb water for the 

 supply of the glands that secrete the gastric juice. 



