62 Veterinary Elements. 



Immediately below the larynx is the windpipe (tra- 

 chea), a flexible tube made up of rings of cartilage, liga- 

 ments, etc. ; lying just above it is the gullet (esophagus). 

 The trachea or windpipe is located in the region of the 

 neck, and at its lower end enters the chest cavity, where 

 it divides into smaller tubes (the bronchi), which again 

 divide into still smaller tubes (the bronchioles), these 

 end in little pockets or sacs (the air cells of the lung). 

 The mucous membrane of the trachea has numbers of 

 cells possessed of wavy tails, known as cilia. These cilia 

 have a continual motion from within outwards, so that if 

 mucus or some foreign particles get into the windpipe, 

 by the motion of these cilia, this material is thrown out. 



The blind pockets or air vesicles of the lungs are 

 formed of a very fine membrane surrounded by very 

 delicate blood vessels. These air cells, the small bron- 

 chioles, blood vessels and nerves go to make up the 

 lungs, which are spongy organs of a rosy flesh color, some- 

 what marbled in appearance; the right lung is some- 

 what larger than the left, the latter being encroached 

 upon by the heart. A healthy lung will float in water. 

 The lung substance in the natural state is very elastic 

 and requires plenty of room for expansion; pressure on 

 the lung tissue, due to lack of room, the result of such 

 causes as overfeeding, feeding bulky in-nutritious feed, 

 sometimes ends in rupture of some of the air cells; this 

 condition prevents the performance of the natural lung 

 work and as a disease is termed Heaves. 



In connection with the lungs the pleura, one of the 

 serous membranes, commands attention. The pleura has 



