Etiology. 429 



tensive motions, throwing- down, rolling, jumping, etc., cause 

 loops of intestine to become twisted around others. 



One may also consider another mode of production. Es- 

 pecially in the horse, loops of small intestine often cross each 

 other in several places under perfectly normal conditions; this 

 arrangement becomes more marked in increased peristalsis, and 

 loops of intestine with a longer mesentery can then move to 

 distant places in the abdominal cavity and below the heavy 

 loops of the large intestine. If the small intestine or the small 

 colon have changed their position in this direction, it may easily 

 happen that the mesenteric veins of the particular loop become 

 compressed to such an extent, that a certain degree of con- 

 gestion and swelling of the intestinal wall occurs. More active 

 movements of the intestines may now include further loops into 

 the displacement, particularly if neighboring loops cannot get 

 out of the way in consequence of tense filling; this will increase 

 the pressure upon the displaced loops and with it the venous con- 

 gestion (Wilms). 



Predisposing causes also play a role in the production of 

 this form of volvulus or torsion, and as such must be men- 

 tioned : Greater filling or greater weight of individual loops of 

 intestine (impaction of feces, circumscribed meteorism, tumor, 

 calculi, parasites), relaxed aljdominal walls, and adhesions be- 

 tween individual parts of intestines. 



Kinking of the intestines (turn around the transverse di- 

 ameter) is rare. It occurs most frequently after loops of intes- 

 tine have become adherent to neighboring organs or to the 

 abdominal wall. However, the small intestine or the small colon 

 will simply be narrowed without the production of disturbances 

 of circulation and its sequelae ; but the stenosis may finally lead 

 to complete closure as in a case of Averous in a goat. Kinking 

 of the left divisions of the colon (flexio coli) or to the cecum 

 (flexio coeci) occurs occasionally in the horse without prelimi- 

 nary adhesions; it is then undoubtedly due to the enumerated 

 mechanical factors. It is accompanied by rapid development of 

 congestion, because the vessels of these parts of the intestine 

 are included in the kinking. Kinking of the apex of the cecum, 

 with anemia and necrosis of this part (Johne) has been ob- 

 served a number of times. 



One of the cases of the authors suggests the occurrence of partial kinking in 

 the large colon. The case was that of a horse that succumbed after having suf- 

 fered for five hours almost continually from colic. Postmortem examination showed 

 kinking of the median wall with its vascular mesocolon, deep into the lumen of the 

 bowel. The kink was found in the region where the transverse divisions go over 

 into the right divisions. The left and the transverse divisions showed a high degree 

 of venous congestion to the point of kinking; nothing abnormal, particularly no 

 thrombi or emboli were found in the arteries of the colon, tlie anterior mesenteric, 

 or the ileo-ccecolic artery. The origin of this kind of displacement may be ex- 

 plained by assuming that moderate bloating occurred from some cause or other and 

 that the median wall of the dilating division of the colon were pressed inward hj 

 some unknown mechanism. 



