402 THE LIVER. 



campheric acid of LATSCHINOFF, by distillation with soda-lime and whicli 

 can be considered as formed from a hydro-aromatic ring by splitting 

 off of water and formation of double bonds. 



Cholic acid crystallizes partly in rhombic plates or prisms with one 

 molecule of water and partly in larger rhombic tetrahedra or octahedra 

 with one molecule of alcohol of crystallization (MYLIUS). These crystals 

 quickly become 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 

 cholic acid is less insoluble. The solutions have a bitter-sweetish 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 

 195 C. According to BONDI and MULLER the melting-point of the per- 

 fectly pure acid is 198. It forms a characteristic blue compound with 

 iodine (MYLIUS). If finely powdered cholic acid is added to 25-per cent 

 hydrochloric acid at the ordinary temperature, a beautiful violet-blue 

 coloration gradually appears, and this color is permanent for some time 

 and then becomes gradually green and yellow. The blue solution shows an 

 absorption band in the neighborhood of the D line (HAMMARSTEN). 



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

 concentrated caustic or carbonated alkali solution they may then be sepa- 

 rated 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 rotatory power of the sodium salt l 

 is (a) D = +30.61 (2.29-per cent concentration) to +27.46 (7.59-per 

 cent concentration). The watery solution of the alkali salts, when not 

 too dilute, is precipitated immediately or after some time by lead 

 acetate or by barium chloride. The barium salt crystallizes in fine, silky 

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

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

 insoluble in water, is soluble in warm alcohol. 



Choleic Acid (C25H 42 O 4 , LATSCHINOFF) is another cholic acid which, 

 according to LASSAR-CoHN, 2 has the formula C24H 40 O 4 . This acid, 

 which occurs in varying but always small quantities in ox-bile, yields 

 dehydrocholeic acid, C 24 H 34 O4, and then cholanic acid C 24 H 34 O 7 , and 

 isocholanic acid on oxidation. 



Choleic acid crystallizes when free from water in hexagonal vitreous 

 prisms with pointed ends, melting at 185-190 C. The crystalline 

 acid containing water melts at 135-140 C. (LATSCHINOFF). The acid 



1 See Vahlen, Zeitschr. f. physiol. Chem., 21. 



2 Latschinoff, Ber. d. deutsch. chem. Gesellsch., 18 and 20; Lassar-Cohn, ibid., 26, 

 and Zeitschr. f. physiol. Chem., 17. See also Vahlen, Zeitschr. f. physiol. Chem., 23. 



