558 SPECIAL PHYSIOLOGY. 



Action of the Pancreatic Juice. 



The pancreatic juice, or so-called abdominal saliva, possesses, like 

 that fluid, in a remarkable degree, the power of converting starch into 

 dextrin and grape sugar. The fresh juice is capable of so converting 

 more than four times its weight of starch ; the substance of the gland, 

 macerated in water, also exhibits this power. Hence, probably, it aids 

 in the metamorphosis of the starch which has escaped the action of 

 the saliva. This, however, is a secondary use of the pancreatic fluid; 

 for the mucus of the stomach and intestine, and the intestinal juice, 

 also subserve this purpose ; moreover, the pancreas is as large in car- 

 nivorous mammalia, the natural food of which contains no starchy 

 matter, as it is in the herbivorous species. 



The action of the pancreatic juice on gelatinoid substances has not 

 been specially studied ; but opinions differ as to its power over albu- 

 minoid bodies. It is by most authorities maintained that it does not 

 digest these substances, because it does not dissolve them in experi- 

 ments out of the body. When the pancreatic juice, or the infusion of 

 the gland-substance employed, has undergone a kind of putrefaction, 

 such solution may occur ; but this is a condition not present in the 

 living body. Moreover, any albuminoid substances macerated in 

 water, will putrefy and slowly dissolve, and such putrefied soluble 

 matter rapidly sets up similar changes in fresh albuminoid substances. 

 Corvisart and Meissner believe, however, that the pancreatic juice is 

 able to peptonize albuminoid substances, but that it only possesses this 

 property when they have been previously mixed with gastric juice and 

 bile, or when they are slightly acidified ; or, as Bernard supposes, only 

 after a certain quantity of the digested food has already passed into 

 the circulation, so as to supply the blood with materials suitable for 

 the secretion of some special product, needed for a very powerful pan- 

 creatic juice. 



Extirpation of the pancreas affords no certain information concern- 

 ing the use of its secretion. According to some, the removal of the 

 gland is followed by the absence of white chyle in the lacteals, and 

 the presence of undigested fat in the contents of the large intestine ; 

 at the same time, emaciation occurs. According to others, when this 

 gland is extirpated, neither a total arrest of nutrition, nor death by 

 starvation, necessarily follow, every constituent of the food still under- 

 going more or less perfect digestion, the office of the pancreatic juice 

 being 'fulfilled by other secretions. Complete degeneration of the 

 pancreas in Man, the liver and other organs remaining healthy, does 

 not necessarily interfere with the digestive process ; but, in certain 

 diseases of this gland, fatty matter has been observed to pass undi- 

 gested through the alimentary canal. The use of the pancreatic juice 

 seems, indeed, to be subsidiary, or complementary, to the other di- 

 gestive fluids ; for it aids the saliva in the converson of starch into 

 sugar. It is said by some to be able, with the gastric juice, to dissolve 

 albuminoid matters, and if, as is generally believed, its chief office is 

 to digest fatty matters, it must co-operate, in some manner, with the 

 bile. 



