178 DISEASES OF THE INTESTINES 



DIARRHEA. 



Definition. This term is applied to a too frequent discharge 

 of more or less fluid feces. The condition may vary greatly 

 in small animals from a slight increase in the daily evacua- 

 tions to repeated evacuations of large quantities of liquid 

 feces. It is important to note that often repeated evacuations 

 of small amounts of liquid feces may occur even when an 

 actual obstruction of the bowels ' (fecal impaction) exists. 



Etiology. The essential condition in diarrhea is an abnor- 

 mal increase of fluid in the feces. The causes, therefore, will 

 be found to be those which occasion a rapid evacuation of the 

 bowel contents, or a reduction in the absorption from the 

 bowels; or an oversupply of fluid in the bowels either from 

 the ingestion of large quantities of water or any over- 

 abundant secretion from the mucous membrane. 



Normally the contents of the small bowels are fluid. They 

 pass from the stomach to the large bowels in a few hours. 

 The contents of the large bowels become gradually hardened 

 from the absorption of the water during their passage through 

 this part of the intestinal tract, which requires in small 

 animals, from twelve to twenty hours. Any conditions 

 therefore that hasten the movements of the contents through 

 the large bowels would tend to make the feces softer or liquid. 

 The same result may occur from a variety of conditions which 

 disturb the process of absorption and keep the feces in a liquid 

 state. Occasionally conditions that influence the absorption 

 from the mucous membrane, such as irritations of various 

 kinds, at the same time excite the secretion of considerable 

 quantities of fluids. These same agents may also increase 

 peristalsis and thus hurry the contents through the bowels. 

 The most common causes of diarrhea therefore are: (a) 

 Drinking excessive quantities of water or eating large quan- 

 tities of fat meat, lard, or butter will result in diarrhea. The 

 unabsorbed fat or its decomposition in the intestinal tract 

 acts as an irritant and greatly increases intestinal activity. 



(6) Foods will sometimes produce diarrhea by their irri- 

 tating action on the mucous membrane. Such substances 

 as table scraps containing fruit stones, parings, or fish, 



