398 



PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



before entering the intestine (Fig. 156). The arrangement of the pan- 

 creatic duets in the bird is represented in Fig. 157. 



The pancreatic juice is a colorless, alkaline fluid secreted by the 

 pancreas or the so-called abdominal salivary glands. It differs from the 

 other digestive secretions in that when freshly formed by a normal gland 

 it contains a large amount of proteids. Its composition varies with the 

 rate of secretion, and when studied as obtained through fistulas differs 

 accordingly as to whether a temporary or permanent fistula has been 

 made. 



Fig. 156.— Pancreas and Duodenum of the Cat. 



a, pylorus ; o, section of duodenum at the level of the glands of Brnnner; 



(Bernard.) 



c c', superior pancreatic 

 duct opening with the hiliary duct into the intestine ; a, mucous membrane of the duodenum ; e, inferior 

 pancreatic duct; el, point of its anastomosis with the descending hrauch of the pancreatic duct; A, com- 

 mon opening of the biliary duct and superior pancreatic duet ; *y pyloric portion of stomach ; v, biliary 

 duct; ppp', pancreas. 



Temporary fistulse of the pancreas are best made on the dog, since in this 

 animal there is the greatest probability of escaping peritonitis, — a complication 

 which if present is disastrous to the success of the operation, for the pancreas is ex- 

 tremely susceptible to inflammation, and as a consequence the secretion becomes 

 perverted and its properties altered. The only difficulty in the operation consists 

 in finding the duct without injuring the gland or its numerous blood-vessels. To 

 be thoroughly successful the operation should be performed as rapidly as possible, 

 so as to avoid exposing the parts any longer than is necessary, while the pancreas 

 should be handled with the greatest gentleness. The operation should be per- 

 formed without employing an anaesthetic, to avoid subsequent vomiting and 

 possible vitiation of the secretion. The dog should receive a hearty meal of bread 

 and meat two hours before the operation, and then should be fastened on his 

 left side. An incision should be made in the right hypochondrium, descending 

 downward from the end of the last rib about five centimeters and parallel with 

 the linea alba, every bleeding point being tied before the peritoneum is opened. 

 Passing the index and middle fingers of the left hand into the wound, the duode- 

 num is easily recognized. The fingers are then carried well clown into the right 

 hypochondrium, and then backward to the convex surface of the duodenum, and 

 keeping their palmar surface directed upward, the fingers are carried behind the 

 duodenum and pancreas, which are then to be drawn together out of the wound. 

 The animal being in full digestion, the tissue of the gland is of a rosy-pink colora- 

 tion. By this manipulation the parts preserve their normal relation, and the an- 



