292 AXATOinCAL TECHNOLOGY. 



Mucosa. — The mucous membrane of tlie small intestine. 



M. circularis. — The circular layer of unstriped muscle. 



M. longitudinalis. — The longitudinal layer of unstriped muscles. 



Ost. amp. Vtr., Ostium ampullae Vateri, az. — The opening or mouth of the ampulla 

 of Vater. 



Submucosa. — The layer of connective tissue between the circular muscle and the 

 muscalaris mucosae. 



Fig. 84, A and B. — Dct. chid., Ductus choledochus communis, az. — The common 

 bile duct. 



Dct. W., Ductus Wirsungianus. — The pancreatic duct opening into the ampulla of 

 Vater. In A, both ducts open at the bottom of the ampulla. This is said by Bernard to 

 be the normal condition. In B, the bile duct extends nearly to the orifice of the ampulla, 

 as in the cat. This is not common in man, although normal in the cat. 



§ 751. Demonstration of the Dvxit of Wirsung, the terminal 

 part of the Ductus choledochus, and the Ampulla of Yater. 



Turn the duodenum to Vm left and trace the ductus choledochus 

 to its point of entrance into the intestine. Now remove the perito- 

 neal covering on the dorsal side of the pancreas just caudad of the 

 termination of the ductus choledochus. Then tear away the sub- 

 stance of the pancreas very carefully, and the duct will be exposed. 

 It looks like an uninjected blood vessel. Trace it for some distance 

 from the intestine and it will be found to divide into two main 

 branches, one for each part of the pancreas (Fig. 81-83). Open the 

 duct about 1 cm. from its point of entrance into the intestine, and 

 pass a beaded bristle into it toward the intestine. With a sharp 

 scalpel, slice away the intestine over the point of entrance of the 

 ductus choledochus communis and the ductus Wirsungianus, mak- 

 ing the slices parallel with the direction of the two ducts. Continue 

 the cutting until the plaster in the ductus choledochus and the 

 bristle in the ductus Wirsungianus are exposed. It will be seeu 

 that the two ducts penetrate the intestinal wall obliquely caudad, 

 and open separately into the ampulla (Fig. 84). The ampulla then 

 opens through a slight papilla into the lumen of the intestine. 



Contrary to the common statement, the two ducts cannot be said 

 to unite at all (Gage, S, 177). 



In some respects it is better to employ a specimen whose hepatic 

 ducts have not been injected with plaster to demonstrate the rela- 

 tion and termination of the two ducts. In this case a bristle should 

 be put into each. 



(B) Ductus Santorini— Lesser pancreatic duct (Fig. 83). — This, 

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

 its demonstration is more difficult. It opens on the left side of the 



