Q66 INTESTINAL OBSTRUCTION. 



is apparently, when appearing, the result of slow textiiral 

 changes, often of an inflammatory, occasionally of a degenera- 

 tive, character affecting the walls of the intestine. Rarely in 

 the horse have we from this condition perfect obstruction of 

 the canal. 



3. Mechanical Entanglement, Alteration of Position, or Dis- 

 placement of Portions of the Boioels. — It is here, in some of the 

 many forms of alteration of position, that Ave meet with the chief 

 causes of perfect obstruction. 



(a) Strangulation or incarceration of portions of the bowel 

 by adventitious products, as bands of lymph, the result of in- 

 flammatory action in connection with the abdominal serous 

 membranes ; or more frequently we find the strangulation 

 carried out by a pedunculated fatty or gland tumour of the 

 mesentery, the neck of the tumour being of sufficient length 

 to warp itself around the bowel, the gradual swelling of which 

 tends to tighten the ligature, occluding the canal and strangu- 

 lating the part. 



(6) Entanglement of the intestine upon itself. This is 

 ordmarily a condition occupying a good extent of the tube, 

 large or small. In the case of the former the colon is found 

 in its double portion thrown one half or completely around on 

 itself, in this way considerably altering its position in the 

 abdominal cavit}^ Entanglement of the small intestines is 

 often associated with twisting and laceration of the mesenteric 

 web by Avliich they are attached to the spine, and is carried 

 out by the passage of a double portion through a loop formed 

 upon the bowel. 



(c) Mesenteric hernia, passage of a portion of the bowel, 

 usually the smaller, through a rent in the peritoneal web, is a 

 common mode of entanglement and strangulation. 



{d) Incarceration of portions of the intestines in cavities or 

 openings which in perfectly healthy animals usually do not 

 permit of their presence, as in im])erfectly closed umbilicus and 

 in excessive dilatation of the inguinal canal. 



(e) Intussusception, volvulus, or invagination, the passage of 

 one portion of the intestine within the part of the tube con- 

 tinuous with it. This is a cause of obstruction of less frequent 

 occurrence than the varied forms of strangulation. It is said 

 by those who have encountered this lesion in both the human 



