CHAPTEE 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 a normal and healthy 

 condition. 



The proportion of water in the blood is about 750 

 parts in 1,000 ; the variation being dependent on the 

 nature of the animal's work, food, state of health, etc. 

 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 contrary, more water be 

 drunk 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 office of the sensation of thirst is to cause the 



