CHOLIC ACID. 423 



can be precipitated from the solution of the alkali salts by the addition 

 of mineral acids, like glycocholic acid (HAMMARSTEN *). 



As repeatedly mentioned above, the two bile-acids split on boiling 

 with acids or alkalies into non-nitrogenous cholic acids and into glycocoll 

 or taurine. Of the various cholic acids the following have been best 

 studied. 



Cholic Acid or Cholalic Acid. The ordinary cholic acid obtained as 

 a decomposition product of human and ox-bile, which occurs, regularly 

 in the contents of the intestine, and also in the urine in icterus, has, accord- 

 int to STKECKER and nearly all recent investigators, the constitution 



fCHOH 

 C24H4o05, = C2oH3i | (CH^OH^. According to MYLius, 2 cholic acid is a 



ICOOH 



monobasic alcohol-acid with one secondary and two primary alcohol 

 groups. CURTIUS 3 has shown by preparing the cholamine, C23H 39 03.NH2, 

 from the above-mentioned (p. 419) cholic-acid azide, with cholic-acid 

 urethane as an intermediary step, that the carboxyl group is not imme- 

 diately connected with the CHOH group, but is combined with the chief 

 nucleus without the neighboring secondary alcohol group. On oxida- 

 tion it first yields dehydrocholic acid, C24Hs405 (HAMMERSTEN) from 

 which by electric reduction, SCHENCK obtained the reducto-dehydro- 

 cholic acid, C24H.3&O5. On further oxidation bilianic add, C24H340g 

 (CLEVE), is obtained, or, more correctly, according to LATSCHINOFF, 

 LASSAR-COHN and PREGL, a mixture of bilianic and isobilianic acids 

 discovered by LATSCHINOFF. On oxidation, bilianic acid yields dlianic 

 add (LASSAR-COHN), whose formula, according to PREGL, 4 is C2oH28Og. 



The products formed on a more active oxidation are of great interest. 

 If we discard the still somewhat problematic cholesterinic acid, we 

 find in these products in the first place choloidanic add which has also 

 been* called cholecamphoric acid and has the formula, CisH^sOg, accord- 

 ing to PREGL. This acid, as well as the acid obtained by LETSCHE 5 

 on the oxidation of cholic acid and with the formula, CigH^gOio, have 

 been obtained by PREGL 6 from the three most closely studied cholic acids, 



1 Zeitschr. f. physiol. Chem., 61. 



2 The important researches of Strecker on the bile-acids may be found in Annal. d. 

 Chem. u. Pharm., 65, 67, and. 70; Mylius, Ber. d. deutsch. chem. Gesellsch., 19. 



3 Ibid., 39. 



4 Hammarsten, Ber. d. deutsch. chem. Gesellsch., 14; Schenck, ibid., 63 and 69; 

 Cleve, Bull. Soc. chim., 35; Latschinoff, Ber. d. d. chem. Gesellsch., 15; Lassar-Cohn, 

 Ber. d. d. chem. Gesellsch., 32; Pregl, Wein. Sitzungsber., Ill, 1902. 



5 Zeitschr. f. physiol. Chem., 61. 

 <> Ibid., 65. 



