ON THE STABLE. 153 



tory direction, and both of these are completely 

 prevented by the pressure of the abdominal 

 muscles and other surrounding parts, so that the 

 only action which it possesses, is simply that of 

 compression. 



The fibres of the muscles which perform 

 this action, are wrapped round the cardiac or 

 receiving orifice of the stomach in a transverse 

 direction, by which means they act as a 

 sphincter, and effectually close it, so as to pre- 

 vent regurgitation, or the return of its contents. 

 Vide plate 10, fig. I— fig. 2 shews the circular 

 muscles of the oesophagus or gullet. 



This prevention from vomiting appears to 

 be a necessary ordination ; for if the horse 

 regurgitated, the food which returned must 

 pass outv/ards through his nostrils, as the pe- 

 culiar formation of the posterior part of his 

 mouth would not permit it to go through that 

 channel. 



The 



