224 CONJUGATED ACIDS. 



cholic acid we cannot, however, consider glycine, as we know it in 

 its isolated state, to be the adjunct of cholic acid, but must rather 

 assume that the true adjunct of cholic acid, as in the case of hip- 

 puric acid, undergoes a change during its separation, by which it 

 forms the body known to us as glycine. If, as in hippuric acid, 

 we regard this adjunct as a group of atoms isomeric with 

 fumaramide, the rational formula of glycocholic acid will be= 

 C 4 H 3 N0 2 .C 48 H 39 9 .HO. 



Combinations. With alkalies and alkaline earths, glycocholic 

 acid forms very soluble salts ; its compounds with the oxides of 

 the heavy metals are, however, insoluble ; the glycocholate of silver 

 alone being soluble in boiling water. 



Glycocholate of soda, NaO.C 52 H 42 NO n , separates from its 

 alcoholic solution, on the addition of ether, in large, glistening, 

 white clusters of radiating needles, resembling wavellite ; it is 

 not crystallisable from its watery or spirituous solutions ; it 

 dissolves very readily both in water and in spirit (1 part dissolving 

 in 2*56 of spirit at 15); when heated it melts, burns with a 

 smoky flame, and leaves an ash containing cyanides. Glyco- 

 cholate of potash behaves in a similar manner. 



Glycocholate of ammonia, H 4 NO.C 52 H 42 NO 115 occurs in crys- 

 tals precisely similar to those of the soda-salt, when it is gradually 

 separated from an alcoholic solution by ether ; it dissolves readily 

 in water, yields ammonia on boiling, and then has a faintly acid 

 reaction. 



Glycocholate of baryta, BaO. C 52 H 42 NO n , is amorphous, has 

 a strongly sweet and slightly bitter taste, is soluble in water and in 

 alcohol, and is not decomposed by carbonic acid. 



Preparation. This acid occurs in the bile of most animals, but 

 it is best prepared from the bile of the ox by one of the two fol- 

 lowing methods. The bile first carefully dried in the water-bath, 

 and subsequently in vacuo, must be extracted with cold absolute 

 alcohol, and ether must be gradually added to the filtered solution, 

 which is thus rendered turbid, and soon deposits a brownish, tough, 

 resinous mass. If the fluid be now only slightly coloured, we 

 must decant it from the semi-fluid precipitate into another vessel, 

 and again gradually add ether; the fluid again becomes milky, and 

 deposits more resinous matter ; after a time, however, glistening 

 star-like tufts of crystals are deposited, which must be washed with 

 alcohol to which a tenth part of ether has been added, and then 

 rapidly placed in vacua, because the crystals, when moist with 

 ether, rapidly deliquesce into a varnish -like mass ; after drying they 



