244 



INTESTINAL DIGESTION. 



tres) ; and its thickness, three-quarters of an inch (1-91 centimetre). It lies 

 behind the peritoneum, which covers only its anterior surface. 



There are nearly always, in the human subject, two pancreatic ducts 

 opening into the duodenum ; one which opens in common with the ductus 

 communis choledochus, and one which opens about an inch (25-4 mm.) above 

 the main duct. The main duct is about an eighth of an inch (3'2 mm.) in 

 diameter and extends along the body of the gland, becoming larger as it 

 approaches the opening. The second duct is smaller and becomes dimin- 

 ished in caliber as it passes to the duodenum. In general appearance and in 

 minute structure, the pancreas resembles the parotid and submaxillary glands. 

 The normal pancreatic juice may be obtained by establishing a temporary 

 fistula in the main pancreatic duct of a living animal (Bernard). This may 

 be done in the dog, the pancreas being exposed by an incision in the right 

 hypochondrium, and a canula of proper size being introduced through a slit 

 made in the duct, and secured by a ligature. The external wound is then 



closed and the 

 end of the tube 

 is allowed to pro- 

 ject from the ab- 

 domen. The fluid 

 as it is dis- 

 charged from the 

 tube may be col- 

 lected in a test- 

 tube, or a thin 

 gum-elastic bag, 

 may be attached. 

 Like the other 

 digestive fluids, 

 the pancreatic 

 juice is secreted 

 in abundance on- 

 ly during diges- 

 tion. It is there- 

 fore necessary to 

 feed the animal 



moderately about an hour before the operation, so that the pancreas may be 

 in full activity. When the gland is exposed at that time, it is filled with 

 blood and has a rosy tint, contrasting strongly with its pale appearance during 

 the intervals of digestion. 



The secretion of normal pancreatic juice is entirely suspended during the 

 intervals of digestion. This fact can be observed by opening animals in 

 digestion and while fasting. During digestion the pancreatic duct is always 

 found full of normal secretion; and during the intervals it generally is 

 empty. The secretion begins to flow into the duodenum during the first 

 periods of gastric digestion, before alimentary matters have begun to pass in 



FIG. 75. Canula fixed in the pancreatic duct (Bernard). 



A, principal pancreatic duct of the dog ; B, smaller pancreatic duct ; c, ligature 

 securing a canula in the principal duct ; D, D, ligature attaching the canula 

 to the intestine, for security ; E, canula ; F, bladder, provided with a stop- 

 cock G, to collect the pancreatic juice ; p, p, pancreas ; i, i, intestine. 



