266 THE COMMON COLICS OF THE HORSE 



the two cases I relate on p. 305, it will be noticed 

 that not only had the animals to shift a heavy load from 

 a standstill, but had to do so up a sharp and greasy 

 incline. The slipping and sliding attempts thus made, 

 with perhaps an occasional pitching forward on to the 

 nose, and sudden violent efforts to recover equilibrium, 

 are the dangerous factors, and certainly would serve to 

 throw the weighted end of the colon into abnormal 

 positions. A history of such work, therefore, must be 

 looked upon with suspicion when read in conjunction 

 with fatal or suspiciously fatal symptoms. Under such 

 circumstances twist or torsion of the colon may, and no 

 doubt often does occur while the animal is actually at 

 work. 



Speaking for myself, however, I must say that I do 

 not think this is at all the usual way in which twist of 

 the double colon occurs. I regard the heavy and ex- 

 hausting work not as an actual cause, but simply as a 

 predisposing factor. In this way : After a day of heavy 

 labour, the horse comes in ravenously hungry. He 

 hastily bolts his food. Impaction of the bowel or 

 tympany, or both, result. Torsion then occurs (a) either 

 through the mere mechanical action of the gas in 

 the interior of the bowel, {b) or as the result of the 

 powerful contractions of the muscular bands in their 

 attempt to deal with the impaction or the gas, as the 

 case may be. 



While, therefore, I agree with Walley and with Smith 

 that torsion of the colon sometimes occurs while the 

 animal is actually at work, I nevertheless wish to point 

 out that in my opinion it far more often takes place sub- 

 sequently, and in the manner I have described above. 



Symptoms. — I am satisfied from my own experience 

 that cases of incomplete torsion, such as those illustrated 



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