242 THE COMMON COLICS OF THE HORSE 



longitudinal axis ? To some extent it may. In fact, it 

 is more than possible that it is in this way many of the 

 cases of torsion of this bowel commence. We may 

 explain it in this way. Assume the second portion of the 

 bowel to be loaded with an abnormally heavy weight 

 of ingesta, and to be making a more than ordinary 

 muscular effort to pass it along. Under these circum- 

 stances, the cramp-like contractions of the bowel muscles, 

 both those of the circular coat and those of the four 

 longitudinal muscular bands of this portion of the bowel 

 working, perhaps at times concurrently, at others inde- 

 pendently, may, and no doubt do, under stress of heavy 

 work, tend to rotate the bowel on its own longitudinal 

 axis. Some degree of torsion in this direction therefore 

 ensues. It cannot be great, however, for the second 

 portion of the bowel in such a case immediately begins to 

 involve with it its attached portion — namely, the third — 

 and the case of torsion at once becomes one of twist of 

 one portion of bowel on or around another. 



This latter, twist of one portion of the bowel over 

 another, is, I think, practically the only form of volvulus 

 we have to consider — that is, in the case of the double 

 colon. The degree of torsion may be from a quarter 

 turn, to a half, three-quarter, or a whole turn (or even 

 more). In either case, however, we have the fact that 

 one portion of the bowel has commenced to turn round 

 another (see Figs. 23, 24, 25 and 26). 



From what we know of the distribution of the colon 

 in the abdominal cavity (see pp. 13 and 246 and Figs. 

 25 and 26), we are able to conceive that torsion of the 

 united portions may occur in any position from the 

 point of origin of the bowel in the right flank to nearly at 

 the extremity of the colic loop, and either with or with- 

 out removal of the pelvic flexure from its normal position. 



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