172 American Quarterly Microscopical Jour)ial. 



the intestine by a contracted orifice. The ductus choledochus ex- 

 tends nearly to the orifice of the ampulla before opening, and 

 forms part of its pyloric boundary. The duct of Wirsung, at 

 first separated from the ductus choledochus by a wedge of the 

 muscular coat, is now close to it, and extends parallel with it 

 for a short distance into the ampulla, and then opens (PI. XIV., 

 Fig. i). After the two ducts come in contact their walls are 

 fused, and it is impossible to separate them in any way 



DESCRIPTION OF PLATE XIV. 



All the figures original, except 2 and 3, which are from Claude-Bernard. They 

 were all carefully outlined by means of a camera lucida, at a distance of 25cm. 

 The magnifying power of the microscope used was computed at the same distance. 

 The same parts are similarly lettered in all the figures of this plate. 



Fig. I. A vertical, longitudinal section of the ampulla of Vater, stained in 

 picrocarmine. The duct of Wirsung had been previously injected with Berlin 

 blue. X 10. 



a. Villi extending to the edge of the aperture of the ampulla. 



b. Crypts of Lieberkiihn, growing shorter toward the opening {f) on the side of 

 the ductus choledochus. 



c. Submucous connective tissue, containing Brunner's glands, and sending a nar- 

 row band to the edge of the aperture of the ampulla. 



d. Circular layer of muscular fibers, arranged in fasiculi, and cut transversely. It 

 extends along the ductus choledochus on the side next to the pylorus; on the op- 

 posite side it thickens and abuts squarely against the duct of Wirsung. 



e. Longitudinal muscular layer, extending nearly as far as the ductus choledo- 

 chus, but becoming thinner. 



f. The contracted opening of the ampulla of Vater, which is at the summit of 

 a large papilla. 



g. The interior of the ampulla, which is traversed by numerous anastomosing 

 folds and processes, their general direction being toward the aperture _/! 



h. The ductus communis choledochus traversing the duodenal wall obliquely 

 from the pylorus, and opening near the aperture of the ampulla. Its interior is 

 divided by numerous anastomosing folds. 



i. Duct of Wirsung entering the intestine somewhat less obliquely than the pre- 

 ceding, and opening sooner. The interior contains many anastomosing processes 

 and folds. 



j. Narrow wedge of the muscular coats between the two ducts. 



Fig. 2. Magnified two diameters. Longitudinal vertical section of the ampulla 

 of Vater in man, from Claude Bernard (1,553, pi. i, 2, fig. 4 bis). This is said 

 by Bernard to be the normal condition. 



//. Ductus choledochus opening at the bottom of the ampulla. 



/. Duct of Wirsung opening into the ampulla at the same level as the preced- 

 ing, but separated from it by a salient fold. 



g. The interior of the ampulla with two folds on the side. 



/. Orifice of the ampulla. 



/, Valvular fold in the duodenal mucous membrane, on the side next the pylorus. 



