HANDBOOK FOR BIO-CHEMICAL LABORATORY. 23 



Glycocholic Acid, C a6 H 4 ,N0 6 , 



Preparation. 1. The precipitate obtained by treating an 

 alcoholic solution of dried decolorized bile with ether is dis- 

 solved in water, and dilute sulphuric acid added until a per- 

 manent and dense turbidity is produced. Allow this liquid 

 to stand a few hours, when glycocholic acid will separate out 

 as fine silky needles. Collect on filter, wash with water, 

 press between folds of filter-paper, and then dissolve in alcohol, 

 using as little alcohol for solution as possible. Add many 

 times its volume of ether, and glycocholic acid will separate 

 out as long silky needles. 



2. Decolorized extract of ox-bile is dissolved in water and 

 the solution treated with a solution of lead acetate. A pre- 

 cipitate of lead glycocholate is produced. Collect on a filter, 

 wash, drain, and mix with alcohol. To this add a solution of 

 sodium carbonate in excess and evaporate to dryness. This 

 converts the lead glycocholate into sodium glycocholate. 

 Remove the sodium glycocholate from the lead glycocholate 

 by extracting the residue with absolute alcohol. Distil off 

 the alcohol nearly to dryness, and evaporate to dryness in a 

 porcelain dish. Dissolve this residue in water, decolorize 

 this solution by animal charcoal, and the glycocholic acid is 

 precipitated from the solution by the addition of dilute sul- 

 phuric acid. The acid thus obtained is purified by crystalli- 

 zation from boiling water on cooling, or by the addition of 

 ether to its solution in absolute alcohol. 



3. Fresh ox-bile is treated with a few drops HC1, which 

 causes the precipitation of the mucoid substances. Filter, 

 and to each 100 c.c. filtrate add 5 c.c. strong HC1. Place in 

 a stoppered cylinder and add 30 c.c. ether for every 100 c.c. 

 bile, shake well, and allow to stand in a cool place. After a 

 time the mixture is found to be converted into a mass of 

 crystals of glycocholic acid. Filter and wash with ice-water 

 until the washings are colorless ; they are then dissolved in 



