Numerous and somewhat discrepant views have at different times been advanced regarding the functions of this fluid: we shall here notice only those functions which are connected with diges tion. One use that has been aserihed to it is to neutralize in the small intestine the acid chyme which emerges from the stomach. But the bile can contribute little or nothing to time neu tralization of the free acid, because, in the first place, the bile is very slightly alkaline, and often perfectly neutral: and, secondly, because the chyme in the intestine is still acid after the ad mixture of the bile. Again, the bile has been as serted to posses a special solvent action on the chyme: but none of the ordinary constituents of the latter seem to be essentially changed. even when digested for a long time with fresh bile. Again, much importance has been attached to the antiseptic aetion of the bile on the contents of the intestinal canal, in favor of which view it is alleged that when no bile is poured into the in testine the faeces have a putrid odor, as is some times observed in patients with jaundice. and as was noticed by Frerichs in animals in which the common bile-duct had been tied. Another use that has been assigned to the bile is that it exert, a stimulating action on the intestinal walls. and thus acts as a natural purgative: and in support of this view it may be mentioned that jaundice (in which the bile does not flow into the intes tine) is often accompanied by extreme constipa tion, and that purified ox-gall, taken either in the form of pill or enema. produces an undoubted purgative action. But the main use of the bile seems to be to promote the digestion of fatty matters: and it accomplishes this end not so much by any solvent chemical action on the fats (which at most is extremely slight), as by a peculiar physieal action hnth on the fats and on the intestinal walls, disintegrating the firmer and impressing on the latter (by ni)istcning the milli) a peculiar condition which singularly fa cilitates the absorption of fatty matters. This view is fully confirmed both by direct experi ments out of the body and by comparing the rela tive qualities of fat that are retained in the body and applied to the purposes of life by animals with biliary fistulous openings and by healthy animals.
Time pancreatic fluid which is poured into the duodenum at the same spot with the bile ( see Fig. 11 is a colorless. clear, somewhat, viscid and ropy fluid. devoid of any special odor. and exhibiting a !strong alkaline reaetion. This fluid. yielded by different dogs with permanent fistulous openings. varies eonsiderably in client lest composition. the collective solid ranging from 1.5 to per cent.. the organic from 0.0 to 1.6. and the mineral matters from 0.02 to 0.75.
The most abundant and important of the solid eonstitncnts is a peculiar substance termed pan (him, or pancreatic diastase or ferment, in combination with soda. to which this fluid its principal chemical and physiological prop Calculating from the quantity of pan creatic juice secreted by dogs of known weight, we may infer that a man weighing 110 pounds secretes daily about 10 minces of this thlid.
one of the chief uses of the pancreatic juice i» relation to digestion is to convert into sugar the amylao•ous or starchy matters ivhieli have escaped the action of the saliva and have passed unchanged into the duodenum. It possesses this property in a far higher degree than the saliva, and, as might be expected in reference to this use, the panereas is found to be much more de veloped in herbivorous than in carnivorous ani mals. Bernard, the representative of the modern school of physiology in France. claims for this Mild another important function—he believes that he has proved that it is solely by the action of this secretion that the fat is reduced to a con dition in which it can be absorlted and digested: that. is to say, that it is decomposed into glycerin and a fatty avid. (See FArs.) This view has, however, not been generally aecepted, and it that although the change de scribed by Bernard takes place fat and pancreatic juice are simply mixed together in a test. tube. it does nit actually take filmy in the intestine, the avid .juice probably as an interfering agent. An attempt has lately been inatle by ('orvisart and to prove that. like the gastric julep. this fluid can dissolve albuminous matters kilt this view ennutd. be sub stantiated. l'onsidering the large quantity of pancreatie fluid which is yielded in twenty-four hours, Schmidt, who has toad the digestive juices the subject of his special study. is of opin ion that the function of this fluid is not so much to promote the conversion of starch into sugar as for the purpose -of diluting the chyme, and for reconverting the soda (which in the pancreas has been separated from the chlorine of the chloride of sodium, and has combined with the panerea• title) into chloride of sodium. Ile shows, from numerical eal•ulations, that more than half of the chloride of sodium existing in the blood whielt circulates through the panereas is broken tip into hydrochlorie acid and soda. of which the former is separated by the gastric glands. while the latter unites with the panereat Me. ticeting again in the duodenum, the hydrochloric acid f11111 the soda. reunite and re-form chloride of sodium, which is again absorbed and reiMters the eircu lit ion This is perhaps one i if the most singular decompositions and reunions oecurring in the animal body.
If the last of the Holds poured into the in testine and coperating in the digestive proeess, the intestimil jtrie,„ we know comparatively lit tle. It is the aggregate secretion of the vari ous glands which we 'erre described as occurring in the wall, of the small intestine. It is a color or sometimes yelh.wi+h, rtpy, viscid fluid, which is invariably alkaline. NN'e are not aware of any special •haraet•ristic constituent in it, Erlich as eeetirs in the other eltylopoietic Its daily quantity is probably ten otIllees. It seems to unite in itself the leading properties of the pancreatic and gastric juices; that is to say, it tesembles the former in starch into sugar„ and the latter in dissolving flesh and other albuminous bodies.