228 'CONJUGATED ACIDS. 



HYOCHOLIC ACID. C 54 H 43 NO 10 .HO. 



Chemical Relations. 



Properties. This acid, discovered and accurately examined by 

 Gundelach and Strecker*, forms a white resinous mass, which melts 

 in water at 100 and, like choloidic acid, maybe drawn out in long 

 threads ; when perfectly dry it does not melt at a temperature 

 under 1 20 ; it is only slightly soluble in water, dissolves readily 

 in alcohol, and not at all in ether ; it reddens litmus. It dissolves 

 unchanged in cold concentrated nitric and sulphuric acids; but 

 when boiled for some time in either of those acids it yields, like gly- 

 cocholic acid, glycine and a resinous acid similar to choloidic acid ; 

 with concentrated sulphuric acid and either sugar or acetic acid;, it 

 yields, like the other biliary acids, a purplish -violet solution ; it is 

 only decomposed by a solution of caustic potash, when the mix- 

 ture is so concentrated as to solidify on cooling. It is unchanged 

 by digestion in moderately concentrated sulphuric acid and peroxide 

 of lead; putrefaction of the bile seems to exert no influence on it ; 

 when treated with fuming nitric acid, or decomposed by chromic 

 acid, it yields the same products as choloidic acid, namely choles- 

 teric acid, butyric acid, caproic acid, &c. 



Composition. According to Gundelach and Strecker, this acid 

 may be obtained in an anhydrous state, so as in its combination 

 with bases to lose no water. From their analyses of the free acid, 

 as well as of its salts, these chemists have deduced the above 

 formula, in accordance with which the free anhydrous acid 

 consists of: 



Carbon 54 atoms .... 70*28 



Hydrogen .... 43 .... 9'33 



Nitrogen 1 .... 3'04 



Oxygen 10 .... 17'35 



100-00 



The atomic weight =5 762*5, and its saturating capacity =1*73 5. 



This acid contains 2 atoms of carbon and 1 atom of 

 hydrogen more, but 1 atom of oxygen less, than glycocholic acid ; 

 the fact that, when treated with concentrated mineral acids, it 

 likewise yields glycine, tends to confirm the hypothesis, that 

 hyocholic acid also contains the gly cine-yielding adjunct isomeric 

 with fumaramide, and that so much plus of carbon and hy- 



* Ann. d. Ch. u. Pharm. Bd. G2, S. 205-232. 



