CHAPTER IX. 

 EXAMINATION OF BILIARY CALCULI. 



Powdered gall-stones extracted with ether in a flask and filtered. 



Solution evaporated : cholesterin (A). Residue (B) treated on the filter 



with dilute hydrochloric acid. 



r ~~i 



Solution (C) calcium salts, some- Residue (D) washed with water, 



times traces of copper. dried and extracted with chlo- 



roform : bile-pigments, espe- 

 cially bilirubin. 



Pour on the finely powdered gall-stones 1 (about 2 g.) in 

 a dry flask about ten times the volume of ether, shake a few 

 times, then filter through a dry filter, and evaporate the 

 ethereal solution. 



1. The cholesterin thus obtained, C 27 H 43 OH, is not quite 

 pure, but often contains some fat. It is sufficiently pure, 

 however, for the following reaction : 2 



(a) Dissolve a part of the cholesterin in hot alcohol, let 

 the solution evaporate spontaneously on a watch-glass, and 

 examine the mass of cholesterin crystals resulting under the 

 microscope: rhombic tablets, frequently with re-entering 



1 Mixture of cholesterin and pigment-stones. 



2 To purify it, dissolve in 80 per cent, alcohol, add a piece of caustic 

 potash, warm in a flask, on the water-bath, evaporate to dryness in a dish 

 on the water-bath, take up the residue with water, shake the mixture with 

 ether (free from alcohol), remove, and evaporate the ethereal extract. 



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