518 DIGESTION IN THE INTESTINES [CII. XXX1Y. 



Composition and Action of Pancreatic Juice. 



The pancreatic juice may bo obtained by a fistula in animals, a 

 cannula being inserted into the main pancreatic duct ; but as in the 

 case of gastric juice, experiments on the pancreatic secretion are 

 frequently performed with an artificial juice made by mixing a weak 

 alkaline solution (1 per cent, sodium carbonate) with an extract of 

 pancreas which is usually made with glycerin. 



Fio. 359. Section of the pancreas of armadillo, showing alveoli and an islet of Langerhans in the 

 connective tissue. (V. 1). Harris.) 



Quantitative analysis of human pancreatic juice gives the follow- 

 ing results : 



Water 97 '6 per cent. 



Organic solids 1'8 ,, 



Inorganic salts . . . . . 0'6 ,, 



In the dog the amount of solids is much greater. 

 The organic substances in pancreatic juice are 



(a) Enzymes. These are the most important both quantitatively 

 and functionally. They are four in number : 



i. Trypsin, a proteolytic or proteoclastic enzyme. In the fresh 

 juice, however, this is present in the form of trypsinogen. 

 ii. Amylopsin, an amylolytic (amyloclastic) enzyme, 

 iii. Lipase, a fat-splitting or lipolytic (lipoclastic) enzyme, 

 iv. A milk -curdling enzyme. 



(b) A small amount of protein matter, coagulable by heat. 



(c) Traces of leucine, tyrosine, xan thine, and soaps. 

 The inorganic substances in pancreatic juice are 



e Sodium chloride, which is the most abundant, and smaller quan- 

 tities of potassium chloride, and phosphates of sodium, calcium, and 



