154: DIGESTION. 



these ducts almost invariably open into the intestine at or near the 

 same point, it was for a long time difficult to decide by which of 

 the two secretions the digestion of the oil was accomplished. M. 

 Bernard, however, first threw some light on this question by ex- 

 perimenting on some of the lower animals, in which the two ducts 

 open separately. In the rabbit, for example, the biliary duct opens 

 as usual just below the pylorus, while the pancreatic duct com- 

 municates with the intestine some eight or ten inches lower down. 

 Bernard fed these animals with substances containing oil, or in- 

 jected melted butter into the stomach ; and, on killing them after- 

 ward, found that there was no chyle in the intestine between the 

 opening of the biliary and pancreatic ducts, but that it was abun- 

 dant immediately below the orifice of the latter. Above this point, 

 also, he found the lacteals empty or transparent, while below it 

 they were full of white and opaque chyle. The result of these ex- 

 periments, which have since been confirmed by Prof. Samuel Jack- 

 son, of Philadelphia/ led to the conclusion that the pancreatic fluid 

 is the active agent in the digestion of oily substances ; and an ex- 

 amination of the properties of this secretion, when obtained in a 

 pure state from the living animal, fully confirms the above opinion. 

 In order to obtain pancreatic juice from the dog, the animal 

 must be etherized soon after digestion has commenced, an incision 

 made in the upper part of the abdomen, a little to the right of the 

 median line, and a loop of the duodenum, together with the lower 

 extremity of the pancreas which lies adjacent to it, drawn out at 

 the external wound. The pancreatic duct is then to be exposed 

 and opened, and a small silver canula inserted into it and secured 

 by a ligature. The whole is then returned into the abdomen and 

 the wound closed by sutures, leaving only the end of the canula 

 projecting from it. In the dog there are two pancreatic ducts, 

 situated from half an inch to an inch apart. The lower one of 

 these, which is usually the larger of the two, is the one best adapted 

 for the insertion of the canula. After the effects of etherization 

 have passed off, and the digestive process has recommenced, the 

 pancreatic juice begins to run from the orifice of the canula, at first 

 very slowly and in drops. Sometimes the drops follow each other 

 with rapidity for a few moments, and then an interval occurs during 

 which the secretion seems entirely suspended. After a time it re- 

 commences, and continues to exhibit similar fluctuations during 



1 American Journ Mud. Sci., Oct. 1S54. 



