126 RESINOUS ACIDS. 



chemically elucidate the formation of cholic acid. That cholic and 

 choloidic acids proceed from conjugated biliary acids, has been 

 already mentioned ; but according to the theoretical views which 

 are at present maintained, cholic acid exists preformed in these 

 biliary acids, just as in every conjugated acid we regard the true 

 acidifying group of atoms as already formed. Without alluding here 

 to the question whether the bile is primarily formed in the blood 

 or in the cells of the liver, we will merely enquire what substances 

 in the animal body yield that group of atoms which we call cholic 

 acid ? Even if many physiological and pathological facts did not 

 support the view that the fats yield the principal material for the 

 formation of the bile, the experiments of which we have made 

 mention regarding the products of oxidation of cholic and choloidic 

 acids, would lead us to the belief that these bodies are closely allied 

 to the fats, and especially to oleic acid ; for we have seen that Red- 

 ten bacher has obtained from choloidic acid when treated with nitric 

 acid precisely the same volatile acids (of the first group) as were 

 yielded by oleic acid under similar treatment, independently of 

 other specific substances. These latter may appropriately be 

 regarded as arising from a group of atoms still hidden in the cholic 

 acid, which group must be assumed to be an adjunct in the cholic 

 acid. For if it be not improbable that such simple acids as acetic 

 acid, butyric acid, &c., are to be regarded as conjugated acids, we 

 are almost compelled to regard an acid like cholic acid with so high 

 an atomic weight, and so considerable an amount of oxygen (that is 

 to say, with so small a saturating capacity) as a conjugated acid. 



From the circumstance of cholic acid yielding these pro- 

 ducts of decomposition, we may conjecture that it is a conjugated 

 oleic acid ; and, assuming this to be the case, there remains as the 

 adjunct the group of atoms (C 48 H 39 O 9 C 36 H 33 O 3 nr) C 12 H 6 O 6 

 whose per-centage composition is the same as that of the choles- 

 teric acid found by Redtenbacher in the products of decomposition 

 of choloidic acid, arid which is therefore polymeric with it (for 

 C 12 H 6 O 6 : C 8 H 4 O 4 =3 : 2). That such polymeric groups of atoms 

 frequently occur in the animal body as conjugated compounds, is 

 obvious from Strecker's* discovery, that hippuric acid is, like the 

 amides (see p. 36), decomposed into nitrogen, water, and an acid 

 whose composition was found to be C 18 H 8 O 8 , but which probably 

 exists as a hydrate C 18 H 9 O 9 , and in that case is polymeric with 

 cholesteric acid. That cholic acid is oleic acid conjugated with the 

 atomic group C 12 H 6 O 6 is merely a hypothetical view which, 

 * Ann. d. Ch. . Pharm. Bd. 68, S. 52 ff. 



