Differentiation. 287 



well. B}' referring back to fig. 67 the position of the spleen is seen to 

 l>c indicated at the right of the stomach (the left with reference to the 

 body), and the duodenum at the left. The pancreas (not shown ) lie 

 behind the stomach and extend from the spleen to the duodenum. The 

 position of the liver and gall bladder is above and to the left of the duo- 

 denum. Each has an outlet duct which unite and form the tube marked 

 <t in the next fig. 



In the birds the pancreas 'are two in number, sometimes three. In 

 some of the lower mammals there are likewise two or more pieces 

 rather loosely connected together. All of them empty their secretions 

 into the duodenum, either by separate ducts or the ducts from the dif- 

 ferent pancreatic bodies join each other and unite with the duodenum 

 or with the bile duct from the liver. In man normal!}* the pancreas is 



FIG. 117. Four figs, to show anomalies 

 in the connection of the pftnercff* with 

 duodenum. ( Owen, after ffyde Halter.) 

 A. Normal. B, C, I). Anomalies. 



a. Bile duct from the liver 

 b. Duct from the larger or head portion of 



the pancreas 



c. Duct from the smaller tail end of pan- 

 creas. 

 d.~ Duodenum. 



only one gland extending from the 

 spleen to the duodenum, but it is 

 sometimes divided Into two parts, 

 as in the lower mammals. In 

 man, the end of the pancreas next 

 the duodenum is the larger, and is 

 called the head ; the end next the 

 spleen is the tail. The pancreas 

 is traversed by two ducts for car- 

 rying its secretion. In fig. 117, 

 b and c represent tiiese ducts. 



FIG. 117. Normally, these two join each 



other, as shown in the fig. marked A, and the one thus formed then 

 passes on to the side of the bile duct, a. These two run side and side 

 till well within the several walls of the duodenum, where they unite in a 

 sort of bulbous chamber called an aiApulla, from which there is a com- 

 mon opening into the duodenum. In the anomalous case, marked B, 

 the main pancreatic duct, 6, proceeds as usual in company with the bile 

 duct, ft, while the duct, c, makes an entirely independent connection with 

 the duodenum. In the case marked C, which is not so common as B, the 

 main duct, 1>, after receiving c proceeds to the duodenum independently of 

 the bile duct a. In the case of D, which is still more rare, the duct, c, be- 

 sides attending to its own business, receives some of the branch ducts 

 normally belonging to >, thus becoming a tube equal to b in size, and the 

 two unite and then join a as usual. ( Quain.) The pancreas varies 



^k/i> 



