MASTICATION AND DIGESTION 65 



unprepared state, and is consequently liable to become 

 decomposed before the gastric juice can act on it. 



The antiseptic properties of gastric juice is well shown 

 by the immunity with which many races of men eat putrid 

 flesh and fish. 



The active principle of gastric juice — 2)epsinc — converts 

 the nitrogenous matters of the food into a soluble form — 

 in])tone — and also serve to split up the fat into a state of 

 fine division, by dissolving the nitrogenous envelopes 

 which enclose the globules. When the food — now called 

 cliyme — leaves the stomach and enters into the small 

 intestine, it becomes mixed with bile and pancreatic juice 

 which flow from a common duct. The action of the fluid 

 which comes from the pancreas (sweetbread) is very 

 similar in its nature to, though much more enegetic, than 

 that of the saliva, the work of which in converting starch 

 and cane sugar into grape sugar it completes. It also, like 

 gastric juice, dissolves albumen. By virtue of its alkaline 

 nature, it makes an emulsion, or soap, with the fat 

 contained in the chyme, which consequently assumes a 

 white appearance, and is then termed cliyU. The particles 

 of fat are thus split up into a very fine state of division, 

 so as to be readily absorbed in an unchanged state, as 

 none of the digestive fluids produce any effect on their 

 composition. The bile acts as a natural purge, the bowels 

 becoming constipated when it is deficient in quantity. 

 It also, by reason of its antiseptic properties, prevents 

 decomposition of the ingesta, prior to their being expelled. 

 In the absence of bile, deleterious gases are evolved in 

 the intestines, and are absorbed into the system, to the 

 detriment of the health of the animal ; in which case the 



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