1 54 EX A MINA TION OF HORSES 



an increased secretion of mucous and by an occasional 

 hemorrhage. 



Pharynx. — This active muscular cavity may give rise 

 to impediment in breathing by paralysis of its dilator 

 muscles, but in this case disease of the brain is most 

 likely to be the cause and so prevent our having such 

 a case brought for our examination as to soundness. 

 The guttural pouches may also be the seat of dis- 

 tension. Practically the pharynx is seldom the seat of 

 disease giving rise to defect in the wind, but as I have 

 pointed out it may be. 



The Larynx is an extremely common seat of unsound- 

 ness in horses. It is liable to 



1. Wasting of the muscles of its left side. 



2. Warty growths on the vocal cords. 



3. Tumours in its ventricles. 



4. Chronic laryngitis. 



The wasting or atrophy of the muscles of one side of 

 the larynx (always the left side) gives rise to " roaring," 

 and its modifications, " grunting " and " trumpeting." 

 This form of unsoundness is almost as bad as "whistling," 

 and is a great obstacle at times to fast paces. It is due 

 to loss of motion of the left side of the larynx through 

 wasting of its muscles. The muscles on both sides of 

 the larynx are supplied by the recurrent or ascending 

 laryngeal nerve. This nerve leaves the pneumogastric 

 at different places for the two sides. On the right it 

 leaves the pneumogastric opposite the first rib, and turns 



