340 DIGESTION. 



not seem to be essential to its peculiar digestive properties. 

 It has been shown, indeed, by Bernard, that the organic prin- 

 ciple alone, extracted from the pancreatic juice and dissolved 

 in water, is capable of imparting to the fluid all the physio- 

 logical characters of the normal secretion. 



The entire quantity of pancreatic juice secreted in the 

 twenty-four hours has been variously estimated by different 

 authors. After what has been said concerning the variations 

 to which the secretion is subject, it is not surprising that 

 these estimates should present great differences. Bernard 

 was able to collect from a dog of medium size from eighty to 

 one hundred grains in an hour ; 1 but it must be remembered 

 that only one of the ducts was operated upon, and that the 

 gland is always very susceptible to irritation. There is no 

 accurate basis for an estimate of the quantity of pancreatic 

 fluid secreted in the twenty-four hours in the human subject, 

 or of the quantity necessary for the digestion of a definite 

 amount of food. 



Unlike the gastric juice, the secretion of the pancreas, 

 under ordinary conditions of heat and moisture, rapidly 

 undergoes decomposition. In warm and stormy weather the 

 alteration is marked in a few hours ; but at a temperature 

 of from 50 to 70 Fahr., it decomposes gradually in from 

 two to three days. The changes which the fluid thus under- 

 goes are interesting, from the fact that some physiologists, 

 having experimented with an altered or an abnormal secre- 

 tion, have failed to recognize certain of the characteristic 

 properties of the normal fluid. 2 As it thus undergoes decom- 

 position, the fluid acquires a very offensive putrefactive odor, 

 and its coagulability diminishes, until finally it is not affected 

 by heat. The alkalinity, however, increases in intensity ; and 



1 Loc. cit. 



2 FRERICHS, in WAGNER'S Handworterbuch der Physiologic, Braunschweig, 

 1846, Bd. in., S. 848. It is stated by this author that the pancreatic juice does 

 not emulsify fats more readily or completely than many other animal fluids. The 

 juice which he used was undoubtedly abnormal, as it was not coagulable by 

 heat. 



