Etiology. 427 



occurred secondarily, in consequence of rolling in the course 

 of other painful intestinal affections or displacements ( strangu- 

 lation, invagination), (Rulf, Johnk, authors' observation). The 

 importance of mechanical factors as a causative agent is also 

 proven by postmortem displacements which are seen particu- 

 larly often if cadavers of horses have been transported before 

 postmortem rigor had set in. Aside from rolling, abnormally 

 intense peristalsis rarely plays a role in the production of dis- 

 placements, and if at all, it does so preferably in displacements 

 of the small intestine or small colon. 



Torsion of tPie left portion of the colon (torsio coli) in 

 horses may be brought about in a double manner. When the 

 tolerably long left portions of the colon are well filled and the 

 horse turns rapidly from one side to the other, it may occur 

 that the left portions are not able to follow rapidly the quickly 

 moving right portions. If now the horse, when lying on one 

 side, turns to the other (Jelkmann), or rolls, no matter for what 

 reason (colicky pains), or if it is thrown and turned (Mayer), 

 then displacement may take place in the manner indicated. In 

 such cases the left portions represent the fulcrum, around which 

 the right portions turn, which are fastened to the upper ab- 

 dominal wall. 



In the majority of cases the divisions of the colon show 

 an opposite behavior when torsion occurs. The right or the 

 transverse divisions form the fulcrum, around which the re- 

 maining free divisions turn around their axis, either towards 

 one side or the other. In reckless lying down or throwing down, 

 in rolling, in rapid gait, or in jumping, that is, in all forms of 

 motion where the abdomen makes an extensive turning or later- 

 al movements, it may likewise occur that the free and quite 

 heavy left divisions of the colon may make swinging or turning 

 motions along the abdominal wall, either to the right or to the 

 left, particularly if they are not well supported by other intes- 

 tines. The upper division may sink down, especially in its ter- 

 minal portion which is more or less filled with voluminous and 

 firm contents, and pull the other divisions with it, either along 

 the abdominal wall or along the median line of the inferior 

 division. The originally not twisted portion will probably not 

 sink into the torsion in addition to the other divisions, because 

 the contractions of the two divisions occur in opposite direc- 

 tions, and so paralyze or neutralize each other. 



Intense and convulsive peristaltic contractions (dysperistalsis), which play 

 an important role, according to the belief of Forssell, cannot, directly, bring about 

 torsion of the colon, in the opinion of the authors, because the connected portions 

 of the colon must remain together even if the contractions are irregular. It could 

 not be well explained how the contracting division could get beneath another, quies- 

 cent division or how the several positions of the colon could be displaced among 

 each other in consequence of abnormally strong contractions. Convulsive contrac- 

 tions play a predisposing role in that they excite colicky pains and cause the ani- 

 mals to throw themselves or roll, and these movements then may cause torsion. In 

 this respect disturbance of circulation caused by thrombosis of the mesenteric arte- 

 ries, acts like other colicky affections with violent pain. 



