434 THE LIVER. 



eggs, in the urine in icterus, and sometimes in gall-stones, although in 

 very small quantities. 



Biliverdin is amorphous; at least it has not been obtained in well- 

 defined crystals. It is insoluble in water, ether, and chloroform (this is 

 true at least for the artificially prepared biliverdin) but is soluble in 

 alcohol or glacial acetic acid, showing a beautiful green color. It is dis- 

 solved by alkalies, giving a brownish-green color, and this solution is 

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

 Biliverdin gives HUPPERT'S, GMELIN'S, and HAMMARSTEN'S reactions, 

 commencing with the blue color. It is converted into hydrobilirubin 

 by nascent hydrogen. On allowing the green bile to stand, also by the 

 action of ammonium sulphide, the biliverdin may be reduced to bilirubin 

 (HAYCRAFT and SCOFIELD *). 



Biliverdin is most simply prepared by allowing a thin layer of an 

 alkaline solution of bilirubin to stand exposed to the air in a dish until 

 the color is brownish-green. The solution is then precipitated by hydro- 

 chloric acid, the precipitate washed with water until no HC1 reaction 

 is obtained, then dissolved in alcohol and the pigment again separated by 

 the addition of water. Any contaminating bilirubin may be removed 

 by means of chloroform. KUSTER has shown that the biliverdin is only 

 formed by the oxygen of the air from bilirubin under certain conditions: 

 The presence of 2 molecules caustic alkali with the addition of water so 

 that the solution contains 0.2 per cent and, a temperature not above 5 C. 

 HUGOUNENQ and DOYON 2 prepared biliverdin from bilirubin by the 

 action of sodium peroxide and a little hydrochloric acid. 



Choleprasin is a green pigment isolated by KUSTER 3 from gall-stones, which 

 is soluble in glacial acetic acid but insoluble in alcohol. It differs from the other 

 bile-pigments by containing sulphur. On distillation with zinc powder it gives 

 the pyrrol reaction, and on oxidation with chromic acid, KUSTER could not 

 observe any formation of haematinic acid. 



Bilifuscin, so named by STADELER. 4 is an amorphous brown pigment soluble 

 in alcohol and alkalies, almost insoluble in water and ether, and soluble with great 

 difficulty in chloroform (when bilirubin is not present at the same time). Pure 

 bilifuscin does not give GMELIN'S reaction. This is also true fof the bilifuscin 

 prepared by v. ZUMBUSCH, S which is more like a humin substance, and the formula 

 of which is, CeJIg'eNyOu. Bilifuscin has been found in gall-stones. Biliprasin 

 is a green pigment prepared by STADELER from gall-stones, and is generally con- 

 sidered as a mixture of biliverdin and bilirubin. DASTRE and FLORESCO, 6 on the 



1 Centralbl. f. Physiol., 3, 222, and Zeitschr. f. physiol. Chem., 14. 



2 Hugounenq et Doyon, Arch, de Phyisol. (5), 8; Kiister, Zeitschr. f. physiol. Chem., 

 59. 



3 Zeitschr. f. physiol. Chem., 47. 



4 Cited from Hoppe-Seyler, Physiol. u. Path. chem. Analyse, 6. Aufl., p. 225. 

 6 Zeitschr. f. physiol. Chem., 31. 



6 Arch, de Physiol. (5), 9. 



