404 NAVIX ox THE HOKSE. 



faces, whicli lie in contact with each other, are of a bright, 

 glistening, whitish color, and throw out a secretion which 

 moistens them and prevent friction, or rubbing. That part 

 of the pleura which lines the ribs is called the j)leura cos- 

 talis, or pleura of the ribs; that which envelopes the lungs 

 is called the loleura ^uhnonaUs, or pleura of the lungs. The 

 use of the pleura is to hold the parts within the chest in 

 their proper place, and to enable the motions of the ribs, 

 lungs, and diaphragm to be performed with ease and free- 

 dom from friction. 



The lungs are liable to inflammation, which is called 

 pneumonia, or lung-fever. They are the seat of consump- 

 tion. The pleura is the seat of pleurisy. Pleurisy is an 

 inflammation of the pleura. 



The capability of the horse for service depends greatly 

 on the capacity of the lungs. The size of the lungs is 

 judged of by the depth, length, and breadth of the chest. 'No 

 horse with a contracted, diminutive chest can long endure 

 the service for which a horse is valuable. Xo organ so 

 much contributes to long life as the lungs. In fact, an ani- 

 mal can not attain great age without large, healthy lungs. 

 It is, then, of the first importance to the farmer to secure 

 a stock of horses with well-formed chests, and known to 

 have healthy lungs. 



THE BMIN AND NERVES. 



The brain is situated within the skull. It is a soft, whit- 

 ish substance. It is divided into three parts — the greater 

 brain, called the cerebrum, the lesser brain, called the cere- 

 hellimi, and the large head of the spinal cord, called the me- 

 dulla oblongata. The brain is the seat of the mind and 



