270 DIGESTION. 



thrown around the duct. The canula should be provided with a well-fitting stylet, with 

 the point rounded so that it may he introduced into the duct with ease ; and the end of 

 the canula should be somewhat roughened, so that the ligature may secure it well in 

 place. The canula will enter the duct for a short distance only, and it should not be in- 

 troduced forcibly. After this has been accomplished, the canula may be steadied by at- 

 taching it with a single stitch to the wall of the intestine. The stylet is now to be with- 

 drawn and the parts carefully returned to the abdomen, leaving the end of the canula 

 projecting at the anterior portion of the wound, which should be carefully closed. Ber- 

 nard recommends to first raise up the fascia and peritoneum with hooks and carefully 

 attach their edges with sutures, and then to close, in the same way, the incision in the 

 muscles and integument. The animal may now be kept upon the table, and the fluid 

 which is discharged from the tube collected in a test-tube, or a thin gum-elastic-bag may 

 be attached. This may be provided with a stopcock, so that the fluid may be drawn off 



at will. 



I 





I 



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. 



Like the other digestive fluids, the pancreatic juice is secreted in abundance only 

 during the process of digestion. It is therefore necessary to feed the animal moderately 

 about an hour before the operation, so that the pancreas may be in full activity. When 

 it 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. 



In performing the above experiment, it is generally better not to employ an anes- 

 thetic agent, as this very frequently produces vomiting, arrests digestion for a time, and 

 consequently interferes with the secretion of the pancreatic juice. This, however, is not 

 always the case. We have sometimes performed the operation with the aid of ether and 

 have obtained a fair amount of fluid. It is also necessary to avoid traction upon the duo- 

 denum as much as possible, for this is almost sure to produce vomiting. To obtain the 

 best results, the operation should be performed rapidly and with very little exposure of 

 the pancreas. In some very successful experiments, Bernard has obtained from sixty 

 to one hundred grains of juice in an hour, from a dog of medium size. 



Some of the most interesting facts developed by Bernard concerning the pancreatic 

 juice relate to phenomena connected with its secretion. It is important to remember 



