The Ampulla of Vater. 171 



haematoxylin, and doubly stained by these agents, and sections 

 of the fresh duct were treated as above, and with dilute acetic 

 acid, yet no muscular layer or even scattered bundles could be 

 found. 



The structure of the human pancreatic duct, as given by 

 Kolliker (17,358), Salter (27,90), Owen (23,497), and Milne-Ed- 

 wards (22,507), corresponds mainly with the description here 

 given of that of the cat. Kolliker states that the wall of the 

 duct is composed solely of connective tissue with elastic fibers, 

 but Salter says (27,89) that there are a few unstriped muscular 

 fibers in the middle coat, judging from the appearance of nuclei 

 upon the addition of acetic acid, although he was never able to 

 see the fibers satisfactorily. 



As the duct of Wirsung approaches the intestine, it nearly 

 meets the ductus choledochus (PI. XII., Figs. I., and II., PI. XIV., 

 Fig. I, h and /). The two penetrate the intestine a very short 

 distance apart, and extend somewhat around it from the dorsal 

 toward the ventral surface, and at the same time obliquely 

 away from the pylorus (PI. XII., Fig. III., and PI. XIV., Fig. i). 

 Within the duodenal wall at this point is quite a large space, 

 the ampulla of Vater, which communicates with the lumen of 



Fig. 4. Stained in picrocarmine. This preparation shows the vascular net 

 work in the duct. Injected with Berlin blue through the superior mesenteric and 

 cceliac arteries. 



h. Vascular net work, much denser in the middle coat, and becoming very fine 

 next the epithelium. 



Figures 5, 6 and 7. Teased from preparations hardened in Miiller's fluid and 

 then in alcohol, stained in picrocarmine. All similarly lettered. All x 516. 



Fig. 5. A single granular cell from a villus near the aperture of the ampulla of 

 Vater. 



a. Striated border of the free end of the cell. 



b. Large, clear nucleus near the narrow, attached extremity. 



c. Nucleolus, granular and deeply stained. 



Fig. 6. Two cells from the duct of Wirsung. Several groups of cells like this 

 were seen where the broad part of one cell was applied against the narrow part of 

 another, most of them were, however, of nearly equal thickness at the two ends. 



d. The divided base of one of the cells. This is common in the ampullar epithe. 

 lium also. 



Fig. 7. Cells from a cross section of a simple glandular depression in the am- 

 pulla (PI. XIV., Fig. 6). 



They were drawn in position but set apart somewhat to show the large process 

 {d), fitting under the base of the next cell. 



e. Basement membrane. 



