CLEA VAGE PRODUCTS OF THE BILE ACIDS. 381 



therefore contain one carboxyl group (COOH), and according to Mylius 1 

 it also contains one secondary (CHOH) and two primary alcohol 

 groups (CH 2 OH). 



The evidence for this is derived from its behaviour on cautious 

 oxidation. It first yields, when oxidised, monobasic dehydrocholalic acid 

 (C 24 H 34 O 5 ), 2 and on further oxidation tribasic bilic, or bilianic acid 

 (C 24 H 34 8 ). 3 These changes may be expressed by supposing that, in 

 the formation of dehydrocholalic acid, the two primary alcohol groups 

 form aldehyde groups (H C = 0), and the secondary group, a ketone 

 group (C = 0), and that in the further formation of bilianic acid the two 

 aldehyde groups pass into (acid or) carboxyl groups, so producing a 

 tribasic acid ; while besides, in the rest of the molecule, an additional 

 ketone group is formed, as shown by the following formulae : 



Cholalic acid, C 20 H 31 (CHOH)(CH 2 OH). 2 (COOH), on oxidation forms, 

 in place of one secondary alcohol group (CHOH) and two primary 

 alcohol groups (CH 2 OH), one ketone group (CO) and two aldehyde 

 groups (COH), thus yielding dehydrocholalic acid, C 20 H 31 (CO)(COH) 2 

 (COOH), in which, on further oxidation, an additional ketone group is 

 formed, and the aldehyde groups change into carboxyl groups (COOH), 

 thus yielding the tribasic acid, bilianic (or bilic) acid, C 19 H 31 (CO.) 2 (COOH) 3 . 



Scarcely anything is known of the arrangement of the atoms in the 

 hydrocarbon part of the molecule. Mylius 4 has obtained a reaction 

 between cholalic acid and iodine, in solution, with the formation of a 

 blue compound, which is crystallisable and becomes easily dissociated in 

 the same manner as iodide of starch. For example, in solution, it 

 becomes decolorised on heating. 



This substance is probably an addition product of cholalic acid and 

 iodine, and so points out that the hydrocarbon radicle of the acid is not 

 fully saturated ; beyond this, however, we know nothing of its composition. 



Desoxycliolalic acid is a reduction compound obtained by Mylius 5 of 

 the formula C 24 H 40 4 . 



Choleic acid 6 was first found in the preparation of cholalic acid from ox 

 bile, and separated from it by means of the more sparing solubility of its barium 

 salt. According to Lassar- Colin, it also occurs in human bile, and its formula 

 is C 24 H 40 4 . Latschinoff, 7 its discoverer, ascribed to it the formula C 25 H 42 4 . 

 From Lassar-Cohn's 8 formula it appears to be isomeric, or perhaps identical, 

 with desoxycholalic acid. 



Fellic acid 9 (C 23 H 40 4 ) is an acid which has been obtained from human 

 bile ; it is crystalline, insoluble in water, and forms insoluble barium and 

 magnesium salts. 



The acids formed by the cleavage of the peculiar bile acids found in the bile 

 of the pig and goose have been already mentioned in treating of these acids. 



1 Ber. d. deutsch. chcm. GeseUsch., Berlin, 1886, Bd. xix. S. 369, 2000. 



2 Hammarsten, ibid., 1881, Bd. xiv. S. 71 (Dehydrocholsaure] ; Lassar-Cohn, ibid., 1892, 

 Bd. xxv. S. 805 ; Ztschr. f. physiol. Chem., Strassburg, 1892, Bd. xvi. S. 488. 



3 Cleve, Bull. Soc. chim., Paris, tome xxxv. 



4 Ztschr. /. physiol. Chem., Strassburg, 1887, Bd. xi. S. 306 ; Ber. d. deutsch. chem. 

 GeseUsch., Berlin, 1887, Bd. xx. S. 683. 



5 Loc. cU. 



6 Cholcinsdure of Latschinoff, Ber. d. deutsch. chem. GeseUsch., Berlin, 1885, Bd. xviii. 

 S. 3039. 



7 Loc. cit. 



8 Ber. d. deutsch. chem. GeseUsch., Berlin, 1894, Bd. xxvii. S. 1339. 



9 Fellinsaure of Schotten, Ztschr. /. physiol. Chcm.. Strassburg, 1887, Bd. xi. S. 268. See 

 also Lassar-Cohn, ibid., 1894, Bd. xix. S. 563. 



