302 HYO AND CHENOTAUROCHOLIC ACIDS. [BOOK II. 



Boiling with saturated baryta water or still better heating in a 

 sealed tube with the same reagent, at the temperature of boiling 

 water, causes taurocholic acid to split up into taurine and cholalio 

 acid, thus : 



C 26 H 46 NS0 7 + H 2 = C^Os + C 2 H 7 NS0 3 . 



Taurocholic acid. Cholalic acid. Taurine. 



When exposed to the air, as well as in the alimentary canal, 

 under the influence of putrefactive organisms, a similar decomposition 

 occurs. 



Recognition Like glykocholic acid, taurocholic acid exhibits 



of taurocholic Pettenkofer's reaction. 



acid - In a mixture of bile acids both the presence and the 



amount of taurocholic acid are determined by fusing with a mixture 

 of sodium carbonate and saltpetre and determining the presence 

 and the amount of the sulphuric formed. 



Hyotaurocholic acid, C^H^NSCV 



This acid, which was formerly known as hyocholeic acid (Strecker), 

 is the sulphur-containing acid of pig's bile. It has not hitherto been 

 obtained in a pure condition. When boiled with alkalies or dilute acids 

 it yields as products of decomposition taurine and hyocholalic acid, C 25 H 40 O 4 

 (see p. 307). 



Chenotaurocholic acid, C 26 H 49 NS0 6 (?). 



This acid, which is present in the bile of the goose 1 , was first inves- 

 tigated by Heintz and Wislicenus 2 and then by Otto 3 . It exists in the 

 bile as a sodium salt. It is separated by the method which, with ox bile, 

 yields Plattner's crystallised bile ; the ether precipitate is however, in the 

 case of the bile of the goose, at first, amorphous. It is washed with a 

 concentrated solution of sodium sulphate, dried, dissolved in absolute 

 alcohol, and the clear filtered solution is precipitated by means of ether 

 (which contains water). In the course of time small rhombic tables of 

 sodium chenotaurocholate separate, which when dried at 140 C. have the 

 composition C 29 H 48 NaNSO 6 . 



The salt is dissolved in water, the solution precipitated with basic lead 

 acetate, the precipitate suspended in alcohol, decomposed by means of 

 H 2 S and filtered. The filtrate on evaporation leaves the acid as an amor- 

 phous residue, soluble both in water and alcohol. 



When boiled with barium hydrate, chenotaurocholic acid yields' taurine 

 and chenocholalic acid, C^H^C^. 



1 Hence the name (xnv, o and 77, gander, goose). 



2 Heintz u. Wislicenus, Pogg. Ann., Vol. cvm. p. 547. 



3 Otto, Zeitsch. f. Chemie, 1868, p. 633. 



