THE ABDOMEN. 139 



across. It has a capacity of about five pints and serves 

 as a storehouse for food. 



The stomach has four coats: 1. a serous coat derived 

 from the peritoneum; 2. a muscular coat of three layers 

 with longitudinal fibers continuous with those of the 

 esophagus, circular fibers, and oblique fibers; 3. an areolar 

 coat, and 4. a mucous coat, which, when the stomach is 

 empty, is thrown into longitudinal folds or rugce, and 

 whose surface is covered with glands, the gastric glands, 

 for the secretion of the digestive fluids. 



The arteries come from the celiac axis and the nerves 

 from the pneumogastric and the solar plexus. 



Ulcer and cancer of the stomach are both rather com- 

 mon. In the former there is apt to be hyper-acidity and 

 in the latter %jw>-acidity, but the rule does not always 

 hold. In cases of ulcer there may be hemorrhage and 

 even perforation. Such hemorrhage can be distinguished 

 from hemorrhage from the lungs by its slightly acid odor 

 and by the frothy character of hemorrhage from the 

 lungs. There is much irritation at the pylorus and where 

 there is irritation there is liable to be cancer. 



Gastric Digestion. In the stomach the food is churned 

 and thoroughly mixed with the gastric juices, and it is 

 also subjected to a propulsive movement that drives it on 

 to the intestine. When it comes to the stomach it is semi- 

 solid and when it has become fluid or semi-fluid, in which 

 state it is known as chyme, it is ready to pass on. Before 

 it can do so, however, it must overcome the strong pyloric 

 sphincter, and this it does by the muscles about the 

 sphincter pushing it constantly on until the sphincter 

 gives way. Probably most of the propulsive movements 

 take place within a few inches of the pylorus. 



The gastric juice is secreted by glands in the wall of the 

 stomach and poured out through little tubules which 

 project from the surface. It is a thin, almost colorless 

 fluid with a sour taste and odor due to the presence of free 

 hydrochloric acid, an important element in digestion. 

 Probably when the stomach is empty and for some twenty 



