EXAMINATION OF A SICK HORSE. 23 



inflammation, as from eruptions, ulcers, or wounds; necrosis of the 

 lower jawbone in front of the first back tooth; and swellings. For- 

 eign bodies are sometimes found embedded in the mucous membrane 

 lining of the mouth or lodged between the teeth. 



The examination of the pharynx and of the esophagus is made 

 chiefly by pressing upon the skin covering these organs in the region 

 of the throat and along the left side of the neck in the jugular gutter. 

 Sometimes, when a more careful examination is necessary, an esoph- 

 ageal tube or probang is passed through the nose or mouth down the 

 esophagus to the stomach. 



Vomiting is an act consisting in the expulsion of all or part of the 

 contents of the stomach through the mouth or nose. This act is more 

 difficult for the horse than for most of the other domestic animals, 

 because the stomach of the horse is small and does not lie on the floor 

 of the abdominal cavity, so that the abdominal walls in contracting do 

 not bring pressure to bear upon it so directly and forcibly, as is the 

 case in many other animals. Beside this, there is a loose fold of 

 mucous membrane at the point where the esophagus enters the stom- 

 ach, and this forms a sort of valve which does not interfere with the 

 passage of food into the stomach, but does interfere with the exit of 

 food through the esophageal opening. Still, vomiting is a symptom 

 that is occasionally seen in the horse. It occurs when the stomach is 

 very much distended with food or with gas. Distention stretches the 

 mucous membrane and eradicates the valvular fold referred to, and 

 also makes it possible for more pressure to be exerted ujDon the stom- 

 ach through the contraction of the abdominal muscles. Since the 

 distention to permit vomiting must be extreme, it not infrequently 

 happens that it leads to rupture of the stomach walls. This has 

 caused the impression in the minds of some that vomiting can not 

 occur in the horse without rupture of the stomach, but this is incor- 

 rect, since many horses vomit and afterwards become entirely sound. 

 Aiter rupture of the stomach has occurred vomiting is impossible. 



In examination of the abdomen one should remember that its size 

 depends largely upon the breed, sex, and conformation of the animal, 

 and also upon the manner in which the animal has been fed and the 

 use to which it has been put. A pendulous abdomen may be the result 

 of an abdominal tumor or of an accumulation of fluid in the abdom- 

 inal cavity; or, on the other hand, it may merely be an indication 

 of pregnancy, or of the fact that the horse has been fed for a long 

 time on bulky and innutritions food. Pendulous abdomen occurring 

 in a work horse kept on a concentrated diet is an abnormal condi- 

 tion. The abdomen may increase suddenly in volume from accu- 

 mulation of gas in tympanic colic. The abdomen becomes small and 

 the horse is said to be " tucked up " from long-continued poor appe- 

 tite, as in diseases of the digestive tract and in fever. This condi- 



