The Ajnpiilla of Vater. 129 



the pyloric region of the stomach to the spleen, by which its left 

 ventral surface may be partly covered, while its dorsal surface 

 rests upon the left kidney. The second division extends from 

 the first, parallel with the left side of the duodenum, to the infe- 

 rior pancreatico-duodenal vessels (PI. XII., Fig. I., branches of 

 10 and 11). It then curves toward the left, and finally sends a 

 narrowed part along the right side of the superior mesenteric 

 vein (Fig. I., 11), nearly meeting a spur from the first division. 



Following Cuvier (i, 585), Hyde Salter (27, 99), and Owen 

 {22,., 495), these parts of the pancreas will be named from their 

 relations, \.\\.^ gastro-splenic and duodenal divisions. 



The duodenal division of the pancreas is very thick next the 

 intestine, and envelops about one-third of its circumference, 

 while its free edge is very thin, thus giving a triangular ap- 

 pearance in a cross-section (Fig. II., 5). 



Differing from the human pancreas, which is only covered on 

 the ventral surface by the mesentery(25, II., 395 ; 27, 83), the cat's 

 pancreas has a complete mesenteric investment, the duodenal 

 division being enveloped by the duodenal mesentery, and the 

 gastro-splenic by the dorsal fold of the great omentum.* 



The ducts of the pancreas arc imbedded in the gland sub- 

 stance throughout their entire extent. The duct of Wirsung 

 extends about a centimeter from the intestine, and then 

 divides into two nearly equal branches, one going to each divi- 

 sion of the pancreas (Fig. I., 8, 4, 5). The duct of Santorini 

 is usually very much smaller in the cat than the preceding, and 

 always opens independently into the intestine at a point upon 

 the left side and farther from the pylorus than the common 

 opening of the ductus choledochus and the duct of Wirsung. 

 The two ducts anastomose very freely (Fig. II., 4, 5, 6). The 

 relative positions of the two ducts are accurately shown in Fig. 

 II. There is a spur of gland substance following each duct 

 to the intestinal wall, and clinging very closely to the duct un- 

 til it penetrates the intestine (Fig. I., 6, 8). At all other points 

 the pancreas is held to the duodenum only by the mesentery, 

 numerous small blood-vessels and loose connective tissue, and 

 can be very easily separated, save where the ducts enter. The 



*This seems to be the normal condition in the Felidae, judging from Prof. Owen's statement: 

 "' The pancreas in the feline tribe is composed of two parts, both having an entire investment 

 of peritoneum " (24, 132). 



