174 DIGESTION". 



The most important ingredient of the pancreatic juice is its animal 

 matter, known as pancreatine. It is this substance which gives to the 

 fluid its tenacious or viscid character, and, in the secretion obtained by 

 the above method, it amounts to over ten per cent, of the whole, 

 being more abundant than all the other solids taken together. It is 

 also considerably more abundant, in proportion, than the albuminous 

 ingredient of any other of the digestive fluids. It is coagulable by 

 heat, by nitric acid, by alcohol, and also by magnesium sulphate added 

 in excess. In this last particular it differs from albumen, which is not 

 affected by magnesium sulphate. Another peculiarity, in which it 

 resembles pepsine, is that after being precipitated by alcohol, it may 

 be again dissolved in water, retaining all its original properties. By 

 some observers it is considered as a mixture of several substances 

 which differ from each other in their chemical relations ; but, taken as 

 a whole, it forms a strongly marked distinguishing ingredient of the 

 pancreatic juice. 



When drawn from the canula several days after its introduction, or 

 obtained by means of a permanent fistula, the secretion is usually more 

 abundant, but poorer in its organic constituents. Schmidt found that 

 in the dog, immediately after the operation, the pancreatic juice was 

 of a thick, tenacious consistency, containing an abundance of solid 

 ingredients, consisting principally of organic matter ; while that ob- 

 tained from a permanent fistula was comparatively thin and watery, 

 containing only from 1.5 to 3.6 per cent, of solids, of which not more 

 than two-thirds consisted of organic matter. Other observers have 

 met with the same difference. The fluid obtained soon after the intro- 

 duction of the canula, during the period of digestion, probably repre- 

 sents most fully the normal secretion. 



The organic matter of pancreatic juice, like that of the other 

 digestive secretions, may be extracted from the substance of the gland- 

 ular tissue. For this purpose the pancreas is taken out from the dog 

 or pig, killed while digestion is going on, a few hours after the inges- 

 tion of food, cut into small pieces, or ground to a pulp with sand, 

 and allowed to macerate for two hours in water at 25 (77 F.). The 

 filtered fluid contains a substance nearly or quite identical in its pro- 

 perties with that contained in the pancreatic juice itself. It may also 

 be obtained, in a form better adapted for permanent use, by placing the 

 freshly divided pancreas for twenty-four hours in absolute alcohol, then 

 separating it from the alcohol, and macerating it for several days in 

 glycerine, which is afterward filtered. The glycerine extracts the or- 

 ganic matter of the glandular tissue, and preserves it without alteration. 

 It may be precipitated at any time from the glycerine solution by the 

 addition of strong alcohol, and afterward dissolved in water. It thus 

 forms a watery extract of the pancreas. 



Physiological Properties of the Pancreatic Juice This secretion 

 has certain well marked characters which indicate that its action is of 



