THE SPLEEN. 383 



communis choledochus is formed by the union of the 

 hepatic duct with the duct of the gall-bladder. The latter 

 is about one inch long ; its lining mucous membrane is 

 arranged in a spiral manner. This arrangement prob- 

 ably assists in filling the gall-bladder. The common bile- 

 duct is about three inches long, is joined by the duct of 

 the pancreas, and empties into the descending portion of 

 the duodenum. 



THE PANCREAS. 



The pancreas is situated behind the peritoneum, 

 just above the superior mesenteric vessels. It is about 

 six inches long, one and a half inches at its greatest 

 breadth, and one inch at the thickest part. It weighs 

 about three ounces. It is a flat, tongue-like organ, 

 which has no distinct investing capsule. It presents a 

 a head, body, and tail. The head is received in the 

 curve of the duodenum; the body is behind the stomach; 

 the tail is small and pointed, and is in relation with the 

 spleen. The upper border is thick, and presents the 

 splenic groove for the accommodation of the splenic 

 artery. The pancreatic duct runs through the middle 

 of the gland from the tail to the head. It is called the 

 duct of Wirsung, and is joined by a second duct, the 

 duct of Greenhow, which arises from the lower part of 

 the head of the pancreas. It is essentially a compound 

 racemose gland, resembling the salivary glands. 



THE SPLEEN. 



The spleen is a ductless gland. It is situated in the 

 left hypochondrium ; it is of a dark-bluish color, about 

 six inches long, three broad, an inch and a half thick, 

 and w r eighs about five ounces. It is dense but friable, 

 and is entirely invested by peritoneum. It is convex 

 externally, slightly concave on the inner surface, where 



