516 



LECTURE XXII. 



Choleic acid has also been oxidized, but this has not served to ex- 

 plain its constitution. We may mention, in passing, that a cholic acid 

 described as fellic acid 1 C 2 3H 4 o04 has been obtained from human 

 bile. In the polar bear another cholic acid has been isolated by 

 Hammarsten 2 which he designated as ursocholeic acid, CigHaoC^ or 



CisH^sO^ 



Our present knowledge does not tell us much concerning the for- 

 mation and destiny of these cholic acids in the animal organism, and 

 we are forced to rely upon assumptions. It is indeed perfectly possible 

 that they are related to cholesterol, although this has never been estab- 

 lished positively. 



The composition of the bile varies not only in amount but also as regards 

 its composition. We shall give a few figures showing the relative amounts 

 of the different constituents. In 1000 parts of bile from the hepatic duct 

 there were found to be present : 3 



Of the inorganic salts present, sodium chloride predominates. Sulphates 

 and phosphates are present only in small amounts. The bile from the gall- 

 bladder shows a somewhat different composition from that taken directly 

 from the bile-ducts. This is due to the fact that while the bile remains 

 in the bladder it becomes thickened, owing to the absorption of some of 

 the water, while at the same time mucin and other substances are given up 

 by the mucous membrane of the bladder. The following analyses show 

 the difference in the percentage composition of the bile from these two 

 sources : 4 



1 G. Schotten: Z. physiol. Chem. 11, 268" (1887). Lassar-Cohn: Ber. 27, 1339 

 (1894). 



3 Z. physiol. Chem. 36, 625 (1902). 



3 Olof Hammarsten: A Text Book of Physiological Chemistry (Mandel), 1908, p. 327. 

 Cf. also Ergeb. Physiol. (Asher and Spiro) 4, 1 (1905), and Z. physiol. Chem. 32, 435 

 (1901). 



4 Olof Hammarsten: Nova acta. Reg. Soc. Upsal, Serie III, 1894. 



