THE PANCREATIC JUICE 



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larly in the gland other collections of cells of a different character, the islands 

 of Langerhans. These cells are considerably smaller, their protoplasm is 

 more granular and less easily stained with hematoxylin, and their nuclei are 

 small and stain deeply. The collections of cells vary in size and shape. 

 The islands of Langerhans' cells are not concerned with the production of 

 the pancreatic juice. The special form of nerve terminations, called 

 Pacinian corpuscles, are often found in the pancreas. 



The secretion of the pancreas has been obtained for purposes of experi- 

 ment from the lower animals and from man in at least one case. A 

 pancreatic fistula is established in the dog by opening the abdomen and 

 exposing the duct of the gland which is then made to communicate with 

 the exterior. In Pawlow's method a circular bit of the intestinal mucous 

 membrane around the mouth of the duct in the intestine is brought to 

 the surface and stitched into the wound. The secretion is then easily col- 

 lected into a vessel suspended under the opening. 



The Pancreatic Juice. Pancreatic juice is colorless, transparent, 

 slightly viscid, and alkaline in reaction. It varies in specific gravity from 

 i . oio to i . 030, according as it is obtained from a permanent fistula, when it is 

 more watery, or from a newly opened duct. The solids vary in a temporary 

 fistula from 80 to 100 parts per thousand, and in a permanent one from 16 to 

 50 per thousand. It is characterized by having three distinct and important 

 enzymes known as trypsin, amylopsin, and steapsin, whose actions are, respect- 

 ively, proteolytic, amylolytic, and lipolytic (fat-splitting). Maltase, which 

 inverts the disaccharides, is also present, and a rennin is found in the pan- 

 creatic juice. 



CHEMICAL COMPOSITION OF PANCREATIC JUICE. (C. SCHMIDT.) 



An extract of pancreas made from the gland which has been removed 

 from an animal killed during digestion possesses the active properties of 

 pancreatic secretion. It is made by first dehydrating in absolute alcohol 

 the gland which has been cut up into small pieces. After the entire removal 



