40 Veterinary Elements. 



(breathing) tracts; it has several openings into it besides 

 those already mentioned, namely, those of the eustachian 

 tubes, which communicate with the ear, a,nd those of the 

 guttural pouches, hollow cavities peculiar to the horse, 

 found at the back of the pharynx; these cavities are 

 sometimes filled with pus, and when thus may cause suf- 

 focation. The pharynx opens behind into the gullet 

 (esophagus), a long musculo-membranous tube, the en- 

 trance to which is located just above and behind the 

 larynx. This tube extends to the stomach, and its path 

 can be seen in the neck during the passage of food or 

 medicine; it is lined with a delicate membrane, and 

 although containing a considerable number of muscular 

 fibres, and therefore elastic is not meant for, nor is it 

 improved by, the forcible passing of solid objects, such 

 as broom handles or whipstocks. At its entrance into 

 the stomach of the horse the mucous membrane is in 

 folds, forming a valve, thus preventing the return of food 

 (vomiting, etc.) to the mouth; in cattle and sheep its en- 

 trance is, however, fuunel-shaped, a condition favorable 

 to the return of food to the mouth. 



The Stomach. The digestive tract lias been described 

 as a tube with sacs or enlargements, the first of which is 

 the stomach. In the horse and pig it is a single sac; in 

 cattle and sheep an organ with four compartments, viz: 

 the paunch or rumen, situated in the left flank of the ani- 

 mal, the honeycomb or reticulum, the many-plies or omasum, 

 the true stomach or abomasum, sometimes termed the rennet. 

 The stomach of the horse resembles a bent tube in shape, 

 with the openings close together on the upper border; 

 it is lined by mucous membrane which shows a well- 



