174 OF FOOD, AND THE DIGESTIVE PROCESS. 



ence that this secretion is not purely excremeutitious, but serves some im- 

 portant purpose in the digestive process. 1 It is not easy, however, to state 

 with precision what this purpose is. The results of many of the experi- 

 ments which have been made to determine it, are vitiated by the fact, that 

 the pancreatic duct in most cases discharges itself into the intestinal tube at 

 the same point with the hepatic, and has thus been frequently involved in 

 operations performed upon it. As the most important constituents of Bile, 

 and the agency of the Liver as an assimilating and depurating organ, will 

 be more appropriately considered elsewhere (chaps, vi and xi), we shall here 

 limit ourselves to the consideration of what may be regarded as the best- 

 established facts in regard to the uses of the biliary secretion in the digestive 

 process. 



124. When Bile is mingled with fresh or artificial gastric juice, a pre- 

 cipitate falls which partly consists of glycocholic acid, 2 partly of albumen 

 rendered insoluble by the taurocholic acid, of muciu and the coloring mat- 

 ter of the Bile, and partly of pepsin, which attaches itself to the precipitate. 3 

 Dr. Daltou, 4 however, states that Bile does not form a precipitate with gas- 

 tric juice holding albuminose (peptones) in solution. These fluids are there- 

 fore not finally antagonistic to each other in the digestive process, though at 

 first they produce a precipitate on admixture. 5 When its action is tested 

 out of the body, by mingling it with the different constituents of food, it is 

 found to exert a slight but distinct action in converting starch into sugar. 6 

 It has no action upon cane-sugar, until it has stood a considerable length of 

 time ; but then it converts it into lactic acid. This change it speedily exerts, 

 as do many other animal substances, upon grape-sugar. It has no action on 

 albuminous substances, even when acidulated. And although it will form 

 an emulsion with and saponify oleaginous matter, and especially the fatty 

 acids, yet the emulsification is less complete than that which is effected by 

 the pancreatic fluid alone. 7 But if the action of the Bile is only subsidiary 

 to that of the Pancreatic Juice, it is certain that it very materially aids the 

 absorption of oleaginous bodies by enabling them to pass more easily through 

 the coats of the intestine, Wisfinghausen 8 and Hoffmann 5 having shown 

 that the force requisite to effect the filtration of an oily substance through 

 an animal membrane is much less when the membrane is moistened with an 

 alkaline fluid, or with bile, than when it is moistened with pure water. Bile 

 appears to be deficient in any materials corresponding to the peculiar fer- 

 ments of the saliva, gastric juice, and pancreatic secretion ; and hence its 

 office in digestion must be of a different character from that of either of 

 those fluids. Bile certainly possesses an antiseptic power, for M. Bernard 

 found that when two similar pieces of meat had been immersed for three 

 mouths, one in a bottle of gastric juice alone, and the other in a mixture of 



1 See Princ. of Comp. Phys., 4tli eel it., \\ 405-4 tl. The simplest condition of the 

 Livor, such as we meet with in the higher Radiata, and in the lower Articulata and 

 Mnllusca, consists in a series of follicles lodged in the walls of the stomach and of 

 the upper part of the intestinal tube. 



- Sri- Burkhart, in Pflu^er's Archiv, 1868. 



1 Hainmarsten, Pfliigor's Archiv, 1870, p. 53. 



4 Human Physiology, 5th edit., 1871, p. 181. 



6 See also So h iff, Pfl'iiger's Archiv, 1870, p. 020. 



6 v. Gurup-Besanez, 1862, p. 467. See v. Wittich, Pflu^cr's Archiv, 1872, Band 

 vi, p. 184. 



Dr. IVnce Jones, in the Medical Times, July 5th, 1851. 

 ' Endosmotisch Ycrsuche, Dissert, i ruing., Dorpnt, 1751. 



tr i 1 1 * . , WL ,-. ~\y ..', "C 1 ^ P A i - _ T~* ___i_j. nf i *i 1 1-. r+ * 



See also Dr. Charles 



Williams, in Prize Essay of the Boylston Med. Soc., 1874. Supplement to Boston 

 Mod. Sun,'.. I, 1874. 



} Ueber die Aufnahmc von Quecksilber, 1854, Wurzburg. 



