22 DISEASES OF THE HORSE. 
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. 
After 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 innutritious 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- 
tion also occurs in tetanus from the contraction of the abdominal 
walls and in diarrhea from emptiness. 
In applying the ear to the flank, on either the right or left side, 
certain bubbling sounds may be heard that are known as peristaltic 
sounds, because they are produced by peristalsis, or wormlike con- 
traction of the intestines. These sounds are a little louder on the 
right side than on the left on account of the fact that the large intes- 
tines lie in the right flank. Absence of peristaltic sounds is always an 
indication of disease, and suggests exhaustion or paralysis of the 
intestines. This may occur in certain kinds of colic and is an un- 
favorable symptom. Increased sounds are heard where the intes- 
tines are contracted more violently than in health, as in spasmodic 
colic, and also where there is an excess of fluid or gas in the intestinal 
canal. 
The feces show, to a certain extent, the thoroughness of digestion. 
They should show that the feed has been well ground, and should, in 
the horse, be free from offensive odor or coatings of mucus. A coat- 
ing of mucus shows intestinal catarrh. Blood on the feces indicates 
severe inflammation. Very light color and bad odor may come from 
inactive liver. Parasites are sometimes in the dung. 
Rectal examination consists in examination of the organs of the 
pelvic cavity and posterior portion of the abdominal cavity by the 
hand inserted into the rectum. This examination should be attempted 
by a veterinarian only, and is useless except to one who has a good 
knowledge of the anatomy of the parts concerned. 
