88 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



with 6 g. of the oxidizing mixture and test for sulphuric acid 

 in the fused mass (see chapter on Milk, page 7). 



Detection of Cholesterin. 



Cholesterin is present in the alcoholic-ethereal fluid, 

 together with the salts of the bile-acids still remaining in solu- 

 tion. Allow the greater part of the ether to evaporate by 

 letting the alcoholic-ethereal solution stand in an open dish, 

 remove the rest of the ether and alcohol by evaporation on 

 the water-bath, dissolve the residue in water, shake the mix- 

 ture with ether, remove the ether and evaporate the ether 

 extract. Try the cholesterin reaction with the residue (see 

 Chapter IX, Examination of Biliary Calculi, page 90). 



II. MUCIN OF THE BILE. 



On the addition of acetic acid to 100 cc. of bile there is 

 formed a resinous precipitate, which is ordinarily called bile- 

 mucin, but whose exact nature is still doubtful. The pre- 

 cipitate also contains glycocholic acid, which may be removed 

 by extraction with alcohol. 



III. PREPARATION OF TAURINE. 



Heat 300 cc. of bile in an evaporating-dish on the sand- 

 bath with 100 cc. of hydrochloric acid until the resinous 

 mass, which separates at first, the so-called choloidic acid, is 

 converted into dyslysin (anhydride of cholic acid). This 

 point may be determined by drawing out the resinous mass 

 in threads with a glass rod. These should solidify at once 

 and should then be quite brittle. It may then be assumed 

 that all the taurocholic acid is decomposed. Decant from 

 the dyslysin and evaporate until sodium chloride begins to 

 separate, filter, evaporate on the water-bath to a small volume 

 (the salt which separates is to be removed by filtering again), 

 pour the fluid remaining into about fifteen times its volume 



