INVERSION OF THE RECTUM 301 



matter, the same as that composing intestinal calculi, when like them 

 it is rendered smooth and polished, and presents the same outward appear- 

 ance. It is, however, readily distinguishable by its lightness, and by 

 the woolly texture it displays on section. "When a minute portion of 

 this concretion is submitted to the scrutiny of the microscope, it is found 

 to be made up of small slightly curved vegetable hairs, one extremity of 

 which is pointed and the other broad and somewhat square. 



What are the conditions which lead to the aggregation of these small 

 bodies, in some instances to the almost complete exclusion of other matters, 

 contained in the bowels, it is impossible to say. 



INVERSION OF THE RECTUM 



Now and again, in the course of violent paroxysms of straining, the 

 rectum, or posterior bowel, is forced through the anal opening, with the 

 inner or mucous membrane turned outward. The extent to which this 

 extrusion may take place varies in different cases from a few inches to 

 two or three feet. Old animals, brood mares in particular, are more 

 liable to inversion of the rectum than younger ones, and especially those 

 affected with habitual constipation, which appears to act as a predisposing 

 cause. Straining is the inducing factor in the mishap, which some- 

 times occurs during the pains of parturition or in the course of an attack 

 of colic, or in violent efforts to empty the bladder when the urinary 

 passage is obstructed. It may also arise in the act of straining from 

 severe irritation of the bowels. 



Symptoms. — Inversion of the rectum is indicated by the protrusion 

 of a round fleshy-looking mass from the anus (fig. 110). At first it pre- 

 sents a pink or pinkish-red hue, but after having been exposed for some 

 time its colour is greatly heightened by engorgement of the vessels with 

 blood, consequent upon interruption to the circulation. In prolonged ex- 

 posure the mucous membrane becomes considerably swollen, and black, and 

 softened by infiltration with serum. In this condition the part becomes 

 painful and irritable, and unless carefully guarded the animal will 

 endeavour to rub it against the wall or stall-posts. Should it succeed, 

 the' softened and inflamed gut may be irretrievably damaged. 



Treatment. — When the bowel has been exposed for some time, and 

 is found to be black, soft, and swollen, an attempt to return it should not 

 be made until the circulation has been restored and the swelling reduced. 

 For this purpose it may require to be scarified with the point of a lancet, 

 i.e. punctured here and there lightly with the instrument to give exit to 

 the serum which infiltrates the tissues, and at the same time relieve the 



