INTESTINAL DIGESTION. 



cific gravity of 1019 (Flint). The quantity of organic matters in the normal 

 secretion is very great, so that the fluid is completely solidified by heat. This 

 coagulability is one of the properties by which the normal fluid may be dis- 

 tinguished from that which has undergone alteration. 



COMPOSITION OF THE PANCREATIC JUICE OF THE DOG (BERNARD). 



Water 900 to 920 



Organic matters, precipitable by alcohol and containing always a 



little lime (amylopsine, trypsine, steapsine etc.) 90 to 73'60 



Sodium carbonate 



Sodium chloride . 



Potassium chloride. . . > 



Calcium phosphate. . . 



1,000 1,000 



The properties of the organic constituents of the pancreatic juice are dis- 

 tinctive. Although, like albumen, these substances are coagulable by heat, 

 the strong mineral acids and absolute alcohol, they differ from albumen in the 

 fact that their dried alcoholic precipitate can be redissolved in water, giving 

 to the solution the physiological properties of the normal pancreatic secre- 

 tion. Bernard has also found that they are coagulable by an excess of mag- 

 nesium sulphate, which will coagulate caseine but has no effect upon albu- 

 men. It is important to recognize this distinction between the organic 

 constituents of the pancreatic juice and other nitrogenized substances, espe- 

 cially albumen, from the fact that the last-named substance has the property 

 of forming an imcomplete emulsion with fats. The name pancreatine, given 

 to the organic matter of the pancreatic juice, is inappropriate, as this sub- 

 stance is now known to be composed of several distinct constituents. 



A ferment, almost if not quite identical with ptyaline, may be extracted 

 from the normal juice by nearly the same processes as those employed in the 

 isolation of the active principle of the saliva. On account of its vigorous 

 action upon starch, this substance has been called amylopsine. 



Trypsine is a ferment capable of acting upon the albuminoids, changing 

 them into peptones. According to Heidenhain, there exists in the secreting 

 cells of the gland a substance called zymogen or more properly, trypsinogen, 

 which, before the secretion is discharged, becomes oxygenated and is changed 

 into trypsine. The action of trypsine on the albuminoids is increased by the 

 addition of small quantities of sodium chloride, sodium glycocholate or sodi- 

 um carbonate and is diminished by acids. 



A substance called steapsine, capable of decomposing fats into fatty 

 acids and glycerine, has been described as one of the organic constituents of 

 the pancreatic juice. This action upon fats, which was described by 

 Bernard, though slight, probably assists in their emulsification. 



The inorganic constituents of the pancreatic juice, beyond giving the 

 fluid an alkaline reaction, do not possess any great physiological interest, 

 inasmuch as they do not seem to be essential to its peculiar digestive proper- 

 ties. It has been shown that the organic constituents alone, extracted from 



