130 THE BILE. 



cholesterin may be used (Experiment 276). After the 

 cholesterin has been removed decompose with acid and 

 proceed as in the preceding experiment, 281. 



283. Convert a portion of the bilirubin into bili- 

 verdin by dissolving in dilute sodium hydrate and letting 

 the solution stand in an evaporating dish. When it has 

 turned green, precipitate with an excess of hydrochloric 

 acid, filter, and wash. 



284. The biliverdin in an impure state can be obtained from 

 ox-bile by precipitating the mucin with several times its volume 

 of alcohol, then precipitating the biliverdin by barium chlorid. 

 Filter, wash with water, and alcohol, then decompose with hydro- 

 chloric acid. The biliverdin is insoluble in the acid. To remove 

 the fat it must be extracted with ether, then the biliverdin can 

 be dissolved in alcohol, which, after filtering, is left to evaporate. 



285. GMELIIST'S TEST. To a solution of bilirubin in 

 dilute alkali add slightly yellow., concentrated nitric acid, 

 holding the tube in a slanting position and pouring slowly 

 so that the acid flows down under the bilirubin solution. 

 Notice the colored rings : green nearest the top, then blue, 

 violet, red, and yellow next to the acid. The acid must 

 not be too yellow or the pigments quickly oxidize and 

 nothing is seen but a yellow color. 



286. HUPPERT'S TEST. To an alkaline solution of 

 bilirubin add lime-water to precipitate the bilirubin. 

 Filter, wash with water, place in a test-tube half full of 

 alcohol slightly acidified with sulphuric acid, and boil for 

 some time. The bilirubin is oxidized to biliverdin and 

 the alcohol becomes colored green or bluish green. 



287. To a little of the bilirubin solution in a test- 

 tube add a very dilute tincture of iodin so that it floats on 

 top. An emerald-green ring is seen between the liquids. 



