THE STOMACH. 



231 



CHAPTER IX. 

 THE ABDOMEN AND ITS CONTENTS. 



THE STOMACH. 



a The oesophagus or gullet, extending to the stomach. 



6 The entrance of the gullet into the stomach. The circular layers of the muscles are very 



thick and strong, and which, by their contractions, help to render it difficult for the 



food to be returned or vomited. 

 e The portion of the stomach which is covered by cuticle, or insensible skin. 

 d d The margin, which separates the cuticular from the villous portion. 

 e e The mucous, or villous (velvet) portion of the stomach, in which the food is principally 



digested. 

 f The communication between the stomach and the first intestine. 

 g The common orifice through which the bile and the secretion from the pancreas pass into 



the first intestine. The two pins mark the two tubes here united. 

 h A smaller orifice, through which a portion of the secretion of the pancreas enters the 



intestines. 



The cesophag-us, as has already been stated, consists of a muscular membranous 

 tube, extending from the posterior part of the mouth down the left side of the neck, 

 pursuing its course through the chest, penetrating through the crura of the diaphragm, 

 and reaching to and terminating in the stomach. It does not, however, enter straight 

 into the stomach, and with a large open orifice ; but there is an admirable provision made 

 to prevent the regurgitation of the food when the stomach is filled and the horse sud- 

 denly called upon to perform unusually hard work. The oesophagus enters the 

 .stomach in a somewhat curved direction — it runs obliquely through the muscular and 

 cuticular coats for some distance, and then its fibres arrange themselves around the 

 opening into the stomach. Close observation has shown, that they form themselves 

 into segments of circles, interlacing each other, and by their contraction plainly and 

 forcibly closing the opening, so that the regurgitation of the food is almost im- 

 possible. 



The following is a simple but accurate delineation of the structure of the termina- 

 tion of the oesophagus, and the manner in which it encircles the orifice of the stomach. 

 We are indebted to Mr. Fermjson, of Dublin, for this interesting discovery. 

 19* 



