HYOCHOLIC ACID. 229 



drogen, and minus of oxygen, are respectively added to, and 

 deducted from the non-nitrogenous acid, that the rational formula for 

 this acid would be C 4 H 3 NO 2 .C 50 H 40 O 8 . But as hyocholic acid 

 when decomposed with nitric acid yields the same volatile fatty 

 acids and cholesteric acid, the non-nitrogenous acid, contained in 

 hyocholic acid, may be presumed to have a constitution analogous 

 to cholic acid (see p. 126), and besides the group of atoms C 12 H 6 O 6 

 which yields the cholesteric acid (C 8 H 4 O 4 ) to contain another fluid 

 fatty acid of the formula C n H n _ 3 O 3 in place of the oleic acid in the 

 cholic acid ; and this in point of fact admits of being calculated by 

 subtracting the group of atoms C 12 H 8 O 8 fromthehydrate of the non- 

 nitrogenous hyocholoidic acid ; C 50 H 41 O 9 - C 12 H 6 O 6 ==C 38 H 35 O 3 , 

 which is exactly the formula of doeglic acid (see p. 116). 



That this calculation is a mere fiction is sufficiently obvious, 

 but we believe that such fictions should not be altogether unnoticed, 

 since they stimulate us to further enquiry, even if it were only to 

 determine whether an acid isomeric or identical with doeglic acid 

 existed in the fat of the pig. 



Combinations. The alkaline hyocholates are not crystallisable ; 

 they are soluble in water and alcohol, but not in ether, which com- 

 pletely precipitates them from their alcoholic solutions. Their 

 taste is bitter without any sweet after-taste, and they redden litmus ; 

 like soaps, they are precipitated from their aqueous solutions by 

 alkaline salts, the precipitate containing the base of the salting added 

 in excess ; they melt and are inflammable when heated ; with the 

 salts of baryta, lime, and magnesia, they yield white precipitates 

 soluble when the mixture is raised to the boiling temperature. 

 Their aqueous solutions are precipitated by most of the metallic 

 salts, but their alcoholic solutions are not affected by these re- 

 agents. On the addition of an acid to the aqueous solution, the 

 hyocholic acid is entirely precipitated. Neutral acetate of lead yields 

 a white precipitate which does not cake on boiling. 



Hyocholate of potash, KO.C 54 H 43 NO 10 , is in its moist state a 

 white amorphous mass which melts in the water-bath, and dissolves 

 as long as it contains either water or spirit. It does not dry at 

 a temperature under 120, 



Hyocholate of soda, NaO.C 54 H 43 NO 10 , forms when dry a 

 brownish mass, which when finely triturated, becomes of a snow- 

 white colour ; it has a persistent bitter taste without any sweet 

 after-taste, Its solutions are neutral, and are not rendered turbid 

 by carbonic acid. It is precipitated from its alcoholic solution 

 by ether, and from its aqueous solution by soda-salts ; it melts. 



