DIGESTIVE SYSTEM. 249 



over upon themselves and turning back and advancing again, 

 and running to the stomach, giving that a covering: in this 

 manner the loose floating production of peritoneum denominated 

 the ometitum, is formed; which consequently consists of four 

 layers of peritoneum. From the stomach the membrane spreads 

 right and left : the left invests the spleen ; the right passes to 

 the liver, and having given the gland a complete coverino-, is 

 continued upon the posterior surface of the diaphragm : the 

 several portions of peritoneum connecting the one to the other, 

 forming the ligaments of the liver. The part of the membrane 

 which comes off" from the posterior parts of the liver extends 

 from it to the duodenum, and from that to the pancreas, to go 

 to form the anterior layer of the mesentery. The kidneys and 

 the pancreas cannot be said to receive peritoneal coverings ; inas- 

 much as the membrane simply passes over their unattached 

 surfaces. 



OF THE STOMACH. 



The stomach is a pouch or bag, formed for the reception of 

 the food as it passes through the esophagus. 



Importance. — It is an organ of singular importance in the 

 body ; and the strongest proof, probably, we have of its being so, 

 is the universality of its existence in animals, from the highest to 

 the lowest amongst them : this is not the case with the brain, 

 much less with the heart ; and it was this circumstance that led 

 Mr. Hunter to regard the presence of a stomach as the chief 

 characteristic between animals and vegetables. The stomach 

 has been emphatically denominated the organ of digestion: be- 

 cause within it, the aliment transmitted by the esophagus in a 

 crude state, undergoes its primary and principal change in a 

 process the object of which is to convert it into material for the 

 support of the body. 



Situation, Position, and Plenitude. — The stomach is situated 

 principally in the left hypochondrium, which it nearly fills, ex- 

 tending more or less into the epigastrium, according to its state 

 of plenitude. Its anterior part lies in contact with the liver ; its 

 left extremity is opposed to the diaphragm and spleen, and it 

 lies in part upon the small, but mainly upon the large intestines. 

 It is evident that the full and empty conditions of the stomach 

 must affect its position in relation to the neighbouring viscera, 

 and that the motions of the diaphragm will alter its situation ; 

 for during the recess of that muscle, it must be pushed more 

 or less into the umbilical region. On the other hand, the action 

 of the diaphragm will be impeded by distention of the abdominal 

 viscera, and more particularly by fulness of the stomach : in- 

 K k 



