The Ampulla of Vater. 175 



paper, describing the ampulla of the elephant.) A few years 

 later, in 1819, appeared the description by Tiedemann of a res- 

 ervoir in the seal {Phoca vitiilijid) like that in the elephant (32, 

 350). The first description of the ampulla in the domestic cat, 

 so far as I know, is that given by Cuvier (5,520), where he says: 

 " The ductus choledochus dilates between the muscular and 

 mucous tissues of the duodenum, and its walls present several 

 small culs-de-sac, which make the cavity anfractuous. It is 

 at the bottom of one of these culs-de-sac that the pancreatic 

 duct opens." 



Most authors consider the ampulla as an enlargement of the 

 ductus choledochus, but Hyde Salter says of the ampulla in 

 man: ''Since the mucous membrane lining the ampulla is of 

 the same structure as that lining the intestine, and unlike that 

 lining the ducts, these latter must be said to open by two dis- 

 tinct orifices at the base of the papilla and not by one at its 

 apex as is usually described; in fact, the lining of the cavity of 

 the papilla is part of the general mucous surface of the duode- 

 num (27, 85)." Bernard (1,551-2) says of PI. XIV., Fig. 2. that 

 the ductus choledochus opens at the bottom of the ampulla, 

 and that from the appearance of the epithelium the membrane 

 lining it should be considered as the continuation of that lining 

 the duct of Wirsung. In Fig. 3, where the ductus choledochus 

 extends almost to the surface of the duodenum, he says of the 

 pancreatic duct which opens at the base of the ampulla: " Point 

 d'abouchement du conduit pancreatique properement dit dans 

 I'ampoule de Vater, qui n'est que sa continuation." As the 

 condition just described in man is the normal one in the cat, so 

 far as the relative extent of the two ducts is concerned, doubt- 

 less one might say with equal propriety that the ampulla in the 

 cat is only a continuation of the duct of Wirsung (PI. XII.. 

 Fig. II., 8, 6; PI. XIV., Fig. i and 3, h). 



In my own investigation on the cat's ampulla, it was found 

 impossible to determine in transverse sections whether a given 

 part belonged to the ductus choledochus, the duct of Wirsung^ 

 or the ampulla proper, as the epithelium etc. seemed to be 

 identical in character in all parts of the section. Hence it was 

 necessary to devise some means of distinguishing the different 

 parts. At first red was injected into one duct and blue sim- 

 ultaneously into the other; but the fluids so mingled in the 

 ampulla that it was impossible to determine the exact limits of 



