264 EXCBETION. 



greatest part is in the 'form of what we know as the tauro- 

 cholate of soda. 



These salts may be readily obtained from ox-bile and 

 separated from each other by the following process : The 

 bile is first evaporated to dryness and pulverized. The dry 

 residue is then extracted with absolute alcohol and filtered. 

 In this part of the process, Dr. Dalton uses five grains of the 

 dry residue to one fluidrachm of alcohol. 1 The filtered fluid 

 is of a clear, yellowish color, and contains fats and coloring 

 matter, in addition to the biliary salts. To precipitate the 

 biliary salts, a small quantity of ether is added, which pro- 

 duces a dense, white precipitate that redissolves by agitation. 

 Another small quantity of ether is again added, and the 

 precipitate thus produced is dissolved by shaking the mix- 

 ture. This process is repeated carefully, adding the ether 

 and shaking the mixture after each step, until the precipi- 

 tate becomes permanent. An excess of ether from eight 

 to ten times the bulk of the alcoholic extract used is then 

 added, the test-tube or flask is carefully corked, and the 

 mixture is set aside to crystallize. Gradually the dense, 

 white precipitate falls to the bottom of the vessel or becomes 

 attached in the form of resinous drops to the sides of the 

 glass ; and in from six to twenty-four hours it begins to form 

 delicate acicular crystals, arranged in rosettes. These are 

 crystals of the glycocholate of soda; and the non-crystal- 

 lizable matter remaining is the taurocholate of soda. 



To separate these two salts, the ether is rapidly poured 

 off, and the crystalline and resinous residue is dissolved in 

 distilled water. On the addition to this solution of a little 

 acetate of lead, the glycocholate is decomposed and precipi- 

 tated in the form of glycocholate of lead, leaving the tauro- 



1 DALTON, Treatise on Human Physiology, Philadelphia, 1867, p. 162, ct seq., 

 and On the Constitution and Physiology of the Bile. American Journal of the 

 Medical Sciences, Philadelphia, 1857, New Series, vol. xxxiv., p. 305, et seq. The 

 details of the processes for the extraction of the biliary salts are taken from 

 Dalton, who has studied this subject very carefully, and whose method is simple 

 and entirely satisfactory. 



