30 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



and purify by repeated solution in alcohol and reprecipitating 

 with water. 



Properties. Biliverdin is amorphous, but it .has occasionally 

 been obtained as green rhombic plates with tunicated ends. It 

 is insoluble in water, ether, pure chloroform, benzol, but 

 readily soluble in ethyl alcohol, methyl alcohol, glacial acetic 

 acid, and in chloroform containing alcohol. It dissolves in 

 alkalies, yielding a brownish-green solution which is precipi- 

 tated by acids, as well as by calcium, barium, and lead salts. 

 Solutions of biliverdin exhibit no definite absorption-bands 

 with the spectroscope. An absorption occurs from the red 

 toward the violet end of the spectrum. 



Cholesterin, C 26 H 44 + H 2 0. 



Preparation. Powdered gallstones are first boiled with 

 water and then repeatedly boiled with alcohol. The solution is 

 filtered quickly through a heated filter, and the cholesterin 

 separates out in a fairly pure condition as the filtrates cool. 

 The crystals are washed with cold alcohol and then boiled 

 with an alcoholic solution of caustic soda, which saponifies 

 the fats present. After the evaporation of the alcohol, extract 

 the cholesterin from the residue by means of ether, which 

 dissolves the cholesterin, but not the soaps; filter and evap- 

 orate the ether, and purify the cholesterin by recrystallization 

 from a mixture of alcohol and ether. 



Properties. Cholesterin crystallizes from anhydrous ether 

 or chloroform as needles containing no water of crystallization, 

 but from alcohol as rhombic transparent plates whose sides 

 and angles often appear broken and whose acute angle is 

 76 30' or 87 30', with 1 mol. water of crystallization. It melts 

 at 145 C. when free from water of crystallization. Cholesterin 

 is insoluble in water, dilute acids, and alkalies. It is readily 

 soluble in boiling alcohol; also in ether, glycerin, chloroform, 

 and benzol, as well as the volatile and fatty oils. Its solutions 



