20 THE COMMON COLICS OF THE HORSE 



of the oesophagus. On the right side of that canal (the 

 portion situated within the lesser curvature) these fibres 

 are wholly wanting. 



A brief consideration of the general arrangement of 

 these fibres of the stomach of the horse will be sufficient 

 to point out that the so-called cardiac sphincter is no 

 myth. Taking the two opposite sets of fibres, those 

 intentionally darkly lined at a, Fig. 5, and those of the 

 cravat-shaped formation at a, Fig. 6, we see at once that, 

 when contraction of the muscular coats of the stomach 

 occurs, the lower end of the oesophagus, just where it 

 enters the stomach, is bound to be gripped. While it is 

 compressed from left to right by the fibres of the deep 

 coat, it is at the same time compressed from right to left 

 by the fibres of the middle coat. 



The sphincter thus formed is an extremely powerful 

 one. Moreover, it is in constant operation. This explains 

 in great part, no doubt, how it is that gases or food 

 accumulated in abnormal quantity inside the stomach 

 gain practically no exit by way of the oesophagus. Save 

 in cases so rare that their occurrence may be reckoned a 

 negligible quantity, everything collected in the stomach, 

 deleterious or otherwise, is bound to pass out by way of 

 the pylorus. 



This one peculiarity alone in the build of the horse's 

 stomach must enormously influence the treatment of 

 several disorders we are afterwards to consider. For that 

 reason I have given it prominence here. 



