BILIARY SALTS. 



445 



the glycocbolate only is acted upon, by the acetate of lead. The glycocholate and the 

 taurocholate of lead are then carefully washed and treated separately with the carbonate 

 of soda, which gives the original salts in nearly a pure state. 



The taurocholate of soda is a proximate principle of the bile ; and it is not necessary 

 to describe fully in detail the purely chemical processes by which it is decomposed. 

 With a little care, the taurocholic acid may be obtained in a state of tolerable purity, and, 

 by prolonged boiling with potash, it may be decomposed into a new acid and taurine. 

 Some confusion exists in the books about the name of this new acid. Strecker calls it 

 choleic acid, and he applies the name of cholic acid to what we have described as glyco- 

 cholic acid. As we have adopted the nomenclature of Lehmann, we shall call it cholic 

 acid. It must be remembered, however, that these substances are formed artificially and 

 are not true proximate principles. They have been described in explanation of the name 

 taurocholic acid, which has been applied to this acid on the assumption that the different 

 biliary acids are formed of cholic acid united with taurine or other basic substances. 



If human bile be treated in the manner just described, frequently no crystalline mat- 

 ter is obtained, and, when it exists, it is in very small quantity. The great mass of the 

 precipitate is composed of the taurocholate of soda. This, when it has been thoroughly 



FIG. 135. Crystals of glycoclwlate of soda; magnified 100 diameters. (Robin.) 



purified, is whitish and gummy, very soluble in water and alcohol, and insoluble in ether. 

 It is melted with slight heat and is inflammable. Its reaction is neutral. It has a pecul- 

 iar sweetish -bitter taste. The proportion of this principle in the bile is always very large, 

 although it is subject to considerable variation. It has very little in common with the 

 salts of fatty origin, either in its general properties or composition, inasmuch as it is 

 entirely insoluble in ether, and its acid contains nitrogen. Another peculiarity in its 



