THE BILE. 167 



On reduction, as during the process of putrefaction, cholalic acid 

 may give rise to the formation of desoxycholalic acid, C 24 H 40 O 4 . On 

 boiling with concentrated solutions of the alkaline hydrates a mixt- 

 ure of the corresponding salts of formic acid, acetic acid, propionic 

 acid, and palmitic acid is obtained, and it is interesting to note that 

 the latter, like cholalic acid, gives Pettenkofer's reaction. 



Hyocholalic acid and chenocholalic acid, which result from the 

 decomposition of hyotaurocholic acid, hyoglycocholic acid, and 

 chenotaurocholic 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 filtration 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. 



Choleic 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 dehydrocJwleic acid, C 24 H 34 O 4 , and then cholanic acid, C 24 H 34 O 8 . 

 It is possibly identical with desoxycholalic 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^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 C 20 H 36 O 4 . 



Ursocholeic acid, C 19 H 30 O 4 or C 18 H 28 O 4 , has been found in the 

 bile of ice-bears (Hammarsten), and is thus a homologue of the 

 common choleic acid. 



