THE BILE. 153 



Hyocholalic add and chenocholalic acidj which result from the 

 -decomposition of hyotaurocholic acid, hyoglycocholic acid, and 

 cheiiotaurocholic acid, respectively, in their general properties and 

 reactions are closely analogous to the common form of cholalic acid 

 that has just been considered. Like the latter, they are trans- 

 formed in the intestinal tract into the corresponding dyslysins, 

 and these in turn yield the original acids on heating with sodium 

 hydrate solution. Both are soluble in alcohol and ether, but 

 insoluble in water. 



Isolation of Cholalic Acid from the Bile. Platner's bile, obtained 

 from the ox, is boiled for twenty-four hours with barium hydrate. 

 The cholalic acid which is thus set free is precipitated by adding 

 an excess of hydrochloric acid. It is then washed with water, 

 dissolved in a dilute solution of sodium carbonate, and repre- 

 cipitated with hydrochloric acid. The precipitate is covered with 

 ether and allowed to stand, when crystallization will gradually occur. 

 The crystals are freed from liquid as far as possible by nitration with 

 the suction-pump, and are redissolved in hot alcohol. The solution 

 is diluted with water until a persisting turbidity develops, and is 

 then set aside in a cold place until crystallization is complete. 



Gholeic Acid. When the biliary acids of ox-bile are decomposed, 

 as just described, a small amount of choleic acid, C 24 H 40 O 4 , is always 

 found associated with common cholalic acid. On oxidation it first 

 yields dehydrocholeic acid, C 24 H 34 O 4 , and then cholanic acid, C 24 H 34 O 8 . 

 It is possibly identical with desoxy cholalic acid (see above). The 

 substance has also been found in human bile. 



Fellic Acid. This acid has been obtained together with common 

 cholalic acid and choleic acid from human bile, where it possibly 

 exists in combination with glycocoll and taurin. Its amount is 

 always small. With Pettenkofer's test it gives a reddish-blue 

 color. On heating, it is decomposed, with the formation of vapors 

 which are strongly suggestive of turpentine. Its formula is given 



as C^H.A-. 



Lithofellic Acid. Lithofellic acid is a substance which is closely 

 related to the cholalic acids just described, and is found in certain 

 gastro-intestinal" concretions of various ruminants. It forms the 

 greater portion of the oriental Bezaar stones, which are obtained 

 from the stomach of the wild goat and antelope. It gives Petten- 

 kofer's reaction, and is said to have the formula 30113,504. 



Taurin. As has been pointed out, taurin is not exclusively 

 found in the bile, but occurs also in the lungs and kidneys and in 

 the muscle-tissue of many animals, and notably in that of the verte- 

 brates. While it is unquestionably of albuminous origin, and prob- 

 ably represents an intermediary product in the katalysis of the 

 organic sulphur compounds of the body, it has thus far not been 

 obtained from this source by artificial means. Unlike the loosely 

 combined sulphur of the albuminous molecule, the sulphur which is 

 present in the taurin molecule cannot be split off on boiling with 



