THE ABDOMEN, INTERIOR. 467 



duodenum, to which it is connected by a duct, is a mass 

 of budding cells that subsequently forms the liver. The 

 fcetal liver, then, is in front of the stomach, between the 

 layers of the anterior mesogaster (future hepatic ligaments 

 and gastrohepatic omentum), by which it is connected to 

 the diaphragm the stomach, and duodenum. Into the last 

 opens the duct of the liver. Behind the stomach another 

 mass of cells springs up from whose growth the spleen is 

 formed ; this also develops between the two layers of the 

 mesogaster. In the same way the pancreas springs from a 

 mass of cells in the mesoduodenum (posterior to the gut). 

 (Diags. 32, 33, 34, e.f.g.} 



Coincident with the rotation of the small and first parts 

 of the large intestine, the stomach, first part of duodenum, 

 and liver turn over toward the right side of the abdominal 

 cavity (Diag. 35), while the spleen is crowded over to left 

 side of the abdomen. 



In order to understand these new relations and how they 

 come to be formed, we must consider how the peritoneal 

 attachments can be shifted. 



There is more surface to be covered than there is peri- 

 toneum to cover it. Some parts must be only partially 

 covered by peritoneum in this case ; this is what really oc- 

 curs. In the beginning there is enough peritoneum to 

 cover the primitive gut, but the gut, liver, spleen, etc., 

 growing faster than the peritoneum, some of them become 

 deprived of their peritoneal covering in part. The attach- 

 ments of the peritoneum to the abdominal wall are also 

 shifted by the peritoneum being drawn up in one direction 

 more than in another, until the base of the original attach- 

 ment is completely altered. For instance, the colon rotates 

 to the right side of the abdomen, the right layer of the 

 mesocolon is taken up by the growth of the other abdomi- 



