156 MANUAL OF PHYSIOLOGY. 



its characters, becoming thin and losing its efficacy, most prob- 

 ably being altered by an abnormal state of the gland. 



An artificial pancreatic juice may be extracted by water from 

 the minced gland taken a few hours after death from an animal 

 which has been killed during active digestion (a couple of hours 

 after eating). This extract, used with proper precautions, will 

 have the same effect as the secretion itself. 



A glycerin solution containing the active principles of the 

 pancreatic secretion may also be made from the pancreas of a dead 

 animal by treating the minced gland for a couple of days with 

 absolute alcohol, removing the alcohol, and substituting sufficient 

 glycerin to cover it, in which it should remain a week or so. This 

 extract, filtered, contains but little else than pancreatic ferments. 



Characters of the Secretion, The pancreatic juice is a 

 very thick, transparent, colorless, strongly alkaline fluid, which 

 turns to a jelly if cooled to C. It often contains about ten 

 per cent, of solids when obtained from a temporary fistula, but it 

 may have as little as two per cent. 



Of these a considerable proportion are organic, namely : 



1. Albumin which is coagulated by boiling. 



2. Alkali albumin, precipitated by acetic acid or by adding 



magnesium sulphate to saturation. 



3. Leucin and tyrosin. 



4. Fats and soaps. 



5. Salts, particularly sodium carbonate, which makes it 



alkaline. 



6. Three ferments, to which it owes its specific action on the 



food-stuffs. 



Mode of Secretion. The pancreas does not continue in a 

 state of activity during the interval between the periods of active 

 digestion. When the gland is at rest it is of a pale yellow color 

 and is flaccid, but during active digestion it becomes more turgid, 

 and assumes a pinkish color from the increased flow of blood. 

 The secretion commences immediately after taking food, and rises 

 rapidly for a couple of hours, then falls and rises again in the 



