DIGESTION 823 



B. Bile. 



1. Characters and Composition. — The bile is the secretion of 

 the liver, and it may be procured for examination — (a) from 

 the gall bladdel^ or (b) from the bile passages by making a 

 tistula into them. This may be temporary when a tube 

 IS placed in the common bile duct, or iJermanent when the 

 common bile duct is ligatured, the fundus of the gall bladder 

 Stitched to the edges of the abdominal wound and an incision 

 then made into it ; the bile thus flows through the gall 

 bladder to the surface. 



Bile which has been in the gall bladder is richer in solids 

 than bile taken directly from the ducts, because water is 

 absorbed by the walls of the bladder, and the bile thus 

 becomes concentrated. 



Analyses of gall bladder bile thus give no information as 

 to the composition of the bile when formed. In several 

 cases, where surgeons have produced biUary fistulas, oppor- 

 tunities have occurred of procuring the bile directly from the 

 ducts during life in man. 



Such bile has a somewhat orange-brown colour, and is 

 more or less viscous, but not nearly so viscous as bile taken 

 from the gall bladder. It has a specific gravity of almost 

 1005, while bile from this gall bladder has a specific gravity 

 of about 1030. Its reaction is slightly alkaline, and it has 

 a characteristic smell. 



It contains about 2 per cent, of solids, of which more 

 than half are organic. 



(1) Bile Salts {Chemical Physiology). — The most abundant 

 solids are the salts of the bile acids. In man the most 

 important is sodium glycoclioLate. Sodium taurocholate 

 occurs in small amounts. These salts are readily prepared 

 from an alcoholic solution of dried bile by the addition of 

 water-free ether, which makes them separate out as crystals. 



Glycocholic acid splits into glycin — amino-acetic acid, 

 HoN.CHj.CO.OH — and a body of unknown constitution, 

 cholalic acid, C04H40O5. 



Taurocholic acid yields amino-ethyl sulphonic acid or 



