38 



the air is cool, or cold, and thus prevent 

 the too rapid dissipation of the heat, and 

 the animal resumes his condition as be- 

 fore. 



The self-regulating heat apparatus will 

 bear some consideration, and it may as 

 well be spoken of in this connection. 



When the air is mild, the coat will re- 

 main smooth. If the air becomes cooler, 

 the coat will rise, just in proportion to the 

 change of temperature, and becomes loose 

 and fluffy in the cold. This, practically, 

 thickens the coat and makes it warmer. 

 If, however, a horse that is sufficiently fed, 

 suffers from cold which the rising of the 

 coat is not adequate to relieve, another 

 automatic operation is set to work, and he 

 begins to shiver; that is, the muscles that 



