

FATE OF THE BILE. 275 



phatics, and the villi are thus in a position to absorb more. [The villi act like numerous small 

 pumps, and expel their contents, which are prevented from returning by the presence of valves 

 in the larger lymphatics.] 



(2) The musculature of the intestine itself seems to be excited, perhaps through the agency 

 of the plexus myentericus. In animals with a biliary fistula, and in which the bile-duct is 

 obstructed, the intestinal peristalsis is greatly diminished, while the salts of the bile-acids 

 administered by the mouth cause diarrhcea and vomiting. As contraction of the intestine aids 

 absorption, bile is also necessary in this way for the absorption of the dissolved food-stuffs. 



(D) The presence of bile seems to be necessary to the vital activity of the intes- 

 tinal epithelium in its supposed function of being concerned in the absorption of 

 fatty particles ( 190). 



(E) Bile moistens the wall of the intestines, and gives to the faeces their normal 

 amount of water, so that they can be readily evacuated. Animals with biliary 

 fistula, or persons with obstruction of the bile-ducts, are very costive. The mucus 

 aids the forward movement of the ingesta through the intestinal canal. [Thus, in 

 a certain sense, bile is a natural purgative.] 



(F) The bile diminishes putrefactive decomposition of the intestinal contents, 

 especially with a fatty diet, 190. [Thus, it is an antiseptic, although this is 

 doubted by v. Voit.] 



(G) When the strongly acid contents of the stomach pass into the duodenum, 

 the glycocholic acid is precipitated by the gastric acid, and carries the pepsin with 

 it (Burkart). Some of the albumin, which has been simply dissolved (but not 

 peptone or propeptone), is also precipitated, by the taurocholic acid {Maly and 

 Emich). The bile-salts are decomposed by the acid of the gastric juice. When the 

 mixture is rendered alkaline by the pancreatic juice and the alkali derived from the 

 decomposition of the bile-salts, the pancreatic juice acts energetically in this alka- 

 line medium (Moleschott). 



[Taurocholic acid and its soda salts precipitate albumin, but not peptone ; glycocholic acid 

 does not precipitate albumin, so that in the intestine the peptone is separated from the albumin 

 (and syntonin), and may therefore be more readily absorbed, while the precipitate adhering to 

 the intestinal wall can be further digested (Maly and Emich). Taurocholic acid behaves in the 

 same way towards gelatin peptone.] 



Bilious Vomit. When bile passes into the stomach, as in vomiting, the acid of the gastric 

 juice unites with the bases of the bile-salts ; sodium chloride and free bile-acids are formed, and 

 the acid-reaction is thereby somewhat diminished. The bile-acids cannot carry on gastric 

 digestion ; the neutralisation also causes a precipitation of the pepsin and mucin. As soon, 

 however, as the walls of the stomach secrete more acid, the pepsin is redissolved. The bile 

 which passes into the stomach deranges gastric digestion, by shrivelling theproteids, which can 

 only be peptonised when they are swollen up (p. 250). 



182. FATE OF THE BILE. Some of the biliary constituents are completely 

 evacuated with the faeces, while others are reabsorbed by the intestinal walls. 



(1) Mucin passes unchanged into the fseces. 



(2) The bile-pigments are reduced, and are partly excreted with the faeces as 

 hydrobilirubin, and partly as the identical end-product urobilin by the urine 

 (177, 3^). 



From meconium hydrobilirubin is absent, while crystalline bilirubin and biliverdin, and an 

 unknown red oxidation-product of them, are present [bile-acids, even taurocholic, and small 

 trace of fatty acids] (Zweifel), so that it gives Gmelin's reaction. Hence, no reduction but 

 rather oxidation processes occur in the fcetal intestine. [Composition. Dary gives 72 7 per 

 cent, water, 23 'Q mucus and epithelium, 1 per cent, fat and cholesterin, and 3 per cent, bile* 

 pigments. Zweifel gives 79*78 per cent, water, and solid's 20 '22 per cent. It does not contain 

 lecithin, but so much bilirubin that Hoppe-Seyler uses it as a good source whence to obtain this 

 pigment. It gives a spectrum of a body related to urobilin.] 



(3) Cholesterin is given off with the fasces. 



(4) The bile-salts are for the most part reabsorbed by the walls of the jejunum 

 and ileum, to be re-employed in the animal's economy. Tappeiner found them in 

 the chyle of the thoracic duct minute quantities pass normally from the blood 

 into the urine. Only a very small amount of glycocholic acid appears unchanged 



