218 DISEASES OF THE RECTUM AND ANUS 



of parasites, etc., and also in part to a weakness of the 

 sphincter muscles or the supporting tissues of the rectum. 



Prolapsus of a part or the entire rectum is also frequently 

 observed, due mainly to excessive straining during constipa- 

 tion, in diarrhea, enteritis, etc. This is common in old dogs 

 from unduly straining during the course of chronic constipa- 

 tion, diarrhea, hemorrhoids, urethral stricture, enlarged 

 prostate glands, rectal tumors, labor pains, or after the use 

 of irritating or hot rectal injections or infusions. Some- 

 times these causes not only lead to prolapsus or intussuscep- 

 tion of the rectum, but other portions of the bowels may be 

 involved, and protrude out through the anal opening. (See 

 Intussusception.) 



Symptoms. Mild cases of eversion of the rectal mucosa 

 are hardly noticeable, except when the animal strains, w r hen 

 the enlargement becomes visible. In more severe cases, the 

 rectal mucosa will appear as a rounded, congested enlarge- 

 ment, protruding out through the anal opening. The condi- 

 tion of the mucosa will depend greatly upon the length of 

 time it has been everted. On close inspection, the mucosa 

 will usually be found to be everted only from one side of the 

 rectum, or in rare instances may be the entire mucosa. It 

 will be found congested, of dark color, hemorrhagic, the 

 external covering desquamated and often hanging in thin 

 shreds. Often the surface bleeds when the parts are manipu- 

 lated. Necrosis may result from exposure, or from the blood 

 supply becoming reduced by the swelling. An eversion of the 

 rectum will at once be recognized by the curved, cylinder- 

 like bowel which protrudes. Some feces will be passed, and 

 will collect around the orifice of the canal. Longer exposure 

 (twenty-four to forty-eight hours) will often lead to inqlura- 

 tion, with foci of ulceration, gangrene, beginning as a rule at 

 the apex of prolapsed portion. The progressive changes 

 which develop will depend very largely upon the length of 

 time the bowel remains exposed. 



Diagnosis. This is not difficult as a close inspection of the 

 parts involved will at once reveal the condition. 



Prognosis. An eversion of the mucosa is always considered 

 favorable, recovery taking place promptly. However, if the 



