154 EXAMINATION 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 ofits 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 
