128 THE COMMON COLICS OF THE HORSE 



charged portion number two, looks small almost to the 

 point of being shrunken. 



A further anatomical fact of importance to be noted in 

 this connection is that a portion of bowel with such an 

 abrupt turn in it as this pelvic flexure should have so 

 free a distribution in the abdomen. We have here a 

 bowel several feet in length, of voluminous build, and 

 designed to carry enormous weights of ingesta, with a 

 heavy and unattached end. Devoid of mesenteric or 

 other stay to hold it in position, this heavy end is free to 

 move at will in the abdomen. This must, one would 

 think, lead at times to troubles which could easily be re- 

 ferred to slight displacement. One could easily imagine, 

 for instance, that displacement, similar to that depicted 

 in Fig. lo, though less in degree, would be able to occur 

 to the point of engendering a troublesome case of obstruc- 

 tion, without leading to actual twist, or causing the 

 animal's death. At any rate, it is astonishing how often 

 in cases of obstructive colic one is able to feel per rectum 

 this particular portion of the intestinal tract quite plainly 

 in a state of dangerous engorgement. 



Again, though to some extent it may be labouring the 

 point, I think another reason for tendency to obstruction 

 at this particular spot may be found in a physiological 

 explanation. Comparable to the sluggishness of the 

 circulation in the distal end of a limb, we may take it 

 that the force of the blood-supply at the pelvic flexure is 

 not so great as elsewhere in the bowel. It is, of course, 

 at the extreme end of both the direct and retrograde 

 colic arteries ; and if stasis of the bowel wall is ever due 

 to imperfect circulation, which in other portions of this 

 work we have admitted it is, then one would quite 

 expect to find the pelvic flexure one of the seats of 

 trouble when such cause is in operation. 



