176 American Quarterly Microscopical Journal. 



either duct. It was found, however, that if only the duct of 

 Wirsung was injected, none of the mass got into the ductus 

 choledochus, hence in transverse sections uninjected parts were 

 known to belong to that duct. In PI. XIV., Figs, i and 4 were 

 prepared in this way.* Not only did the epithelium of the am- 

 pulla and ducts appear identical, but their walls were covered 

 with papilliform processes and simple glandular depressions, 

 which seemed to be similar in the three situations (PI. XIV., 

 Fig. 6). The sections were stained in haematoxylin or picro- 

 carmine, or unstained. As to the similarity of the epithelium 

 of the duodenum to that of the ampulla in the cat, there seems 

 to be but very little; they are certainly not identical. i. The 

 cells of the ampulla do not have a striated or hyaline border as 

 do those of both the villi and crypts of Lieberkiihn, Quain 

 (25,362), Strieker (31,388). 2. Goblet cells are rarely or never 

 found in the ampulla. With a power of 675 diameters, I have 

 carefully examined the epithelium of all parts of the ampulla, 

 following it to the level of the crypts of Lieberkiihn, but neither 

 goblet cells nor those having a striated border could be found, 

 although in the same section the striated border of the cells of 

 the villi was so plain that they looked almost as though they 

 were ciliated, and goblet cells were very plentiful both in the 

 villi and the crypts of Lieberkiihn. 



Turning for a moment to the cross sections of the duct of 

 Santorini in its passage through the intestinal wall, it is seen to 

 be divided into two compartments in the first section (PI. XIII., 

 Fig. i); but in a section nearer the orifice the divisions are nu- 

 merous, and the appearance is like the cross sections of the 

 ampulla of Vater (PL XIII., Fig. 2). The epithelium, the pap- 

 illiform processes, and the glandular depressions of this duct 

 within the intestinal wall are similar to those in the ampulla. 



The anastomosing folds and processes in the ampulla, the 

 duct of Wirsung, and the ductus choledochus, being arranged 

 somewhat as are the valves in the veins, allow a flow toward the 

 orifice into the intestine, but greatly impede one in an opposite 

 direction. It would probably be impossible for any solid mat- 

 ter to get into either duct, for it would be caught by some of 



* The extent and course of the ducts within the intestinal wall are much more easily deter- 

 mined in macroscopic inve>;tigations if the duct of Wirsung be first injected with plaster of Paris 

 colored blue, and after it has set, the ductus cholechodus may be injected with a similar mass 

 colored red. The whole should be put into strong alcohol for half a day or more. 



