FORM OF THE STOMACH. 31 



of the mediastinum, it preserves the same course to the fourth 

 dorsal vertebra, when it assumes the middle position and pro- 

 ceeds downwards, with the aorta to its left, and the pericardium 

 before it. About the ninth dorsal vertebra it inclined again 

 rather to the left, and somewhat forward, to arrive at the aper- 

 ture in the diaphragm through which it passes. 



Throughout this course it is connected by cellular membrane 

 to the contiguous parts ; and this investiture of cellular mem- 

 brane has been called its External Coat. 



While the oesophagus is in the posterior mediastinum it is in 

 contact with several small absorbent glands, especially when it 

 first assumes a situation to the right of the aorta. These glands 

 were formerly believed to be particularly connected with this 

 tube, but they are now considered as belonging to the absor- 

 bent system. They are sometimes greatly enlarged. 



Of the Stomach. 



This most important organ, which occasionally exerts a 

 powerful influence upon every part of the body, appears very 

 simple in its structure. 



It is a large sac, which is so thin when much inflated, that at 

 first view it seems membranous, but upon examination is found 

 to be composed of several lamina or coats, each of a different 

 structure. It is of considerable length, but incurvated. It is 

 much larger at one extremity than the other, and changes so 

 gradually in this respect, that it would appear conical, if it were 

 straight. It is not, however, strictly conical unless it is greatly 

 distended ; for when moderately distended, a transverse section 

 is rather oval than circular. It is, therefore, considered as 

 having two broad sides or surfaces, and two edges, which are 

 the curvatures. It has been compared by the anatomists of 

 different nations to the wind sac of the musical instrument called 

 the bagpipe.* The orifice in which the oesophagus terminates 



* The student ought not to attempt to acquire an idea of the form of the 

 stomach without demonstration, for a view of one moment will be more 

 serviceable than a long description. 



