252 THE COMMON COLICS OF THE HORSE 



sweeps together all the scattered atoms, and forms them once 

 more into a string of material. This remarkable movement is 

 unaffected by the action of cocaine or nicotine, which have 

 been shown to inhibit at once the ordinary peristaltic move- 

 ments. 



' Besides peristaltic and pendular movements, another has 

 been described in the dog much slower, but also rhythmical, 

 whicli may be carried out for twenty or thirty minutes at 

 intervals of two hours, even when the canal is empty. 



' We have been told by Colin that digestion in the small 

 intestines of the horse is carried on by peristalsis and anti- 

 peristalsis, the fluid travelling from stomach to ileum, and from 

 the ileum towards the stomach. Pendular movements are of 

 no value in the small intestines of this animal, as the entire 

 material, until the ileum is reached, is fluid, so that there are 

 no strings of food to be segmented. This may account for 

 pendular movements of the bowels not having been observed 

 in the horse. 



■ In the first and third portions of the colon of the horse the 

 ingesta travel by their own gravity ; in the second and fourth 

 portions they travel against gravity, as in the caecum. As the 

 first and fourth and second and third portions of the colon are 

 united, the curious result follows that material is passing along 

 each section apparently in two opposite directions. 



' The frequency of intestinal affections in the horse causes 

 the canal to be of exceptional interest. When the cascum is 

 found completely inverted into the colon, as if a hand had 

 been passed through the colo-caecal opening, laid hold of the 

 apex of the crecum, and drawn the entire bowel within the 

 first portion of the colon, it is then that the question of 

 muscular movements so strongly presents itself. Or, again, 

 what is far commoner and equally fatal — viz., displacement or 

 actual twist of the large bowel, or a complete twist of the 

 small intestine, leaving the bowels in such indescribable com- 

 plexity that the parts cannot be unravelled, even when removed 

 from the body. Finally, a condition rare in the horse, prob- 

 ably in all animals, but still well recognized, in which tele- 

 scoping of the small bowels occurs, known as " intussusception." 

 It is impossible to believe that muscular action of the intes- 



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