172 DIGESTION. 



its essential particulars, in most of the lower animals. In the dog and 

 cat, there are two ducts opening into the intestine, one of them in juxta- 

 position with the orifice of the biliaiy duct, the other from one to three 

 centimetres farther down. The lower of these ducts is usually, though 



Fig. 46. 



PORTION OF HUMAN PANCREAS AND DUODENUM. a. Cavity of duodenum, b. Orifice 

 of the pancreatic duct. c. Orifice of lower pancreatic duct. (Bernard.) 



not always, the larger of the two, and they generally communicate 

 with each other by a transverse branch, in the substance of the gland, 

 before opening into the intestine. Even in the human subject, as shown 

 by Bernard, Kolliker, and Sappey, there is often a smaller accessory duct 

 opening into the intestine, sometimes above and sometimes below the 

 situation of the principal one. The most marked peculiarity in the 

 arrangement of the parts is seen in the rabbit, where the pancreatic duct 

 is single, but opens into the intestine at a distance of from 30 to 40 

 centimetres below the orifice of the biliary duct. 



The pancreatic juice has been obtained in many instances from the 

 living animal by opening the abdomen during the act of digestion, and 

 inserting a silver canula into the principal pancreatic duct, immediately 

 before its entrance into the intestine. The canula being secured in its 

 position by a ligature placed round the duct, the parts are returned 

 into the abdominal cavity, and the external wound closed with sutures, 

 leaving the open extremity of the canula projecting between its edges. 

 The secretion is thus diverted from the intestine, and may be collected 

 for examination as it flows from the canula. This operation has been 

 done most frequently upon the dog, but also upon the rabbit, the ox, 



