THE LIVER. 149 



Cholalic acid crystallizes partly with one molecule of water, in 

 rhombic plates or prisms, and partly in larger rhombic tetrahedra 

 or octahedra with 1 mol. of alcohol of crystallization (MYLIUS). 

 These crystals become quickly opaque and porcelain- white in the 

 air. They are quite insoluble in water (in 4000 parts cold and 750 

 parts boiling), rather soluble in alcohol, but soluble with difficulty 

 in ether. The amorphous cholalic acid is less insoluble. The 

 solutions have a sweetish-bitter taste. The crystals lose their 

 alcohol of crystallization only after a lengthy heating to 100-120 C. 

 The acid free from water and alcohol melts at -j- 195C. 



The alkali salts are readily soluble in water, but when treated 

 with a concentrated caustic or carbonated alkali solution may be 

 separated as an oily mass which becomes crystalline on cooling. 

 The alkali salts are not readily soluble in alcohol, and on the 

 evaporation of the alcohol they may crystallize. The specific 

 rotary power of the sodium salt is (<*)D = -f 31.4. The watery 

 solution of the alkali salts, when not too dilute, is precipitated 

 immediately or after some time by sugar of lead or by barium 

 chloride. The barium salt crystallizes in fine, silky needles, 

 and it is rather insoluble in cold, but somewhat easily soluble in 

 warm water. The barium salt, as well as the lead salt which is in- 

 soluble in water, is soluble in warm alcohol. 



To prepare cholalic acid we boil ox-bile for 18-36 hours 

 with strong caustic alkali, or, better, with as much barium hydrate 

 as the boiling liquid will dissolve. During the boiling add when 

 necessary more barium hydrate. The boiling-hot liquid is strained 

 and concentrated until a crystalline mass separates in large quantity. 

 This mass is separated from the mother-liquor and strongly pressed 

 and recrystallized a few times from boiling water. The recrystal- 

 lized barium salt is now dissolved, and the solution decomposed by 

 hydrochloric acid. The acid which separates is dissolved in boiling 

 alcohol, and the acid generally separates as crystals immediately on 

 cooling. By recrystallization from ethyl alcohol and finally from 

 methyl alcohol the acid may be readily obtained in pure white crys- 

 tals the size of a pea. 



Choleic Acid, C^H^A, is another cholalic acid named by 

 LATSCHI^OFF, which is obtained from ox-bile with ordinary 

 cholalic acid, though in very, small amounts (hardly ^ the quan- 

 tity of the latter). The barium salt of this cholalic acid is 



