CHAPTER XI 
DISEASES OF THE ALIMENTARY TRACT AND OF 
THE DIGESTIVE FUNCTION 
THE digestive system includes the mouth, throat, 
esophagus or gullet, stomach and intestines, with the 
glands which pour their secretions into this tract, such 
as the liver, salivary glands and pancreas. 
The differences in the mouths of animals are very 
marked. In the horse the soft palate, or curtain between 
the mouth and the throat cavity, is long, and is so 
constructed that it prevents the horse from breathing 
through the mouth. Cattle and sheep have no incisors, 
or front teeth, on the upper jaw, but, instead, a pad 
of cartilage against which the lower incisor teeth close 
in biting grass. In pigs the teeth are set in a con- 
tinuous row in the upper and lower jaws. In horses 
there is an interdental space between the incisors and 
the molars or grinders. In male horses there is in 
this space a single canine or “bridle” tooth. These 
are also found occasionally in mares. 
The stomach of the horse is rather small and the 
bowels are capacious. In ruminants—those animals 
which chew the cud, such as the cow and sheep — there 
are four stomachs. The first is the rumen or paunch, 
which lies on the left side. In adult cattle it has a 
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