Daniel G. Revell 



445 



the lumina of the ducts within the boAvel wall when the latter is 

 stretched by distension. Casts of the lumina when the bowel is not 

 distended are made by opening the first part of the duodenum along 

 its ventral side to expose the orificial papillae (vide infra), cleaning the 

 mucous surface, dehydrating it with absolute alcohol and sealing up the 

 orifices with celloidin, then injecting as above under low pressure. Or 



Fig. 



-Enlarged view of lobe of pancreas of dog to show lobulation 



the sealing up may be omitted and the relations of the bile-opening 

 and Wirsung's can then be exactly determined as the injection solution 

 and bile flow from the openings, pressure on the gall-bladder causing 

 the bile to be expelled. 



ToPOGKAPHY. — The pancreas in the dog is tongue-shaped, being 20- 

 45 cm. long, 2-4 cm. wide and 1.5-2.5 cm. thick. Its size is quite 

 variable, even in dogs of equal weight. It has three surfaces, of which 

 two are broad and constant and one is narrow and may be discon- 

 tinuous. The cross section is therefore like an isosceles triangle. The 

 gland is somewhat loosely bound together by connective tissue into 

 lobules and these again into larger lobules, until finally lobes of very 



