BILIRUBIN, BILIVERDIN. 433 



green biliverdin. Then follows a blue coloring-matter which HEINSIUS 

 and CAMPBELL call bilicyanin, and STOKVIS calls cholecyanin, and which 

 shows a characteristic absorption-spectrum. The neutral solutions of 

 this coloring-matter are, according to STOKVIS, bluish-green or steel-blue 

 w r ith a beautiful blue fluorescence. The alkaline solutions are green 

 and have no marked fluorescence, and show three absorption-bands: 

 one, sharp and dark, in the red between C and D, nearer to C; a second, 

 less well defined, covering D; and a third between E and F, near E. 

 The strongly acid solutions are violet-blue and show two bands, described 

 by JAFFE between the lines C and E, separated from each other by a 

 narrow space near D. A third band between b and F is seen with dif- 

 ficulty. The next oxidation step after these blue coloring-matters is 

 a red pigment, and lastly a yellowish-brown pigment, called choletelin, 

 by MALY, which in neutral alcoholic solutions does not give any absorp- 

 tion-spectrum, but in. acid solution gives a band between b and F. On 

 oxidizing cholecyanin with lead peroxide, STOKVIS 1 obtained a product 

 which he calls choletelin, which is quite similar to urinary urobilin, to 

 be discussed later. 



Bilirubin is best prepared from gall-stones of oxen, these concretions 

 being very rich in calcium bilirubin. The finely powdered concrement 

 is first exhausted with ether and then with boiling water, so as to remove 

 the cholesterin ^nd bile-acids. In order to remove the mineral con- 

 stituents it is better to use 10 per cent acetic acid instead of hydrochloric 

 acid (KUSTER 2 ). A green pigment is now removed by extraction with 

 alcohol, and the choleprasin is extracted with hot glacial acetic acid. 

 After washing with water it is dried, and extracted repeatedly with boil- 

 ing chloroform. The bilirubin separates from the chloroform as crusts, 

 which are treated once or twice in the above manner. It is then extracted 

 with alcohol and precipitated from its chloroform solution by alcohol, or 

 crystallized from boiling dimethylaniline. Further details are given by 



KtJSTER. 3 



The quantitative estimation of bilirubin may be made by the spectro- 

 photometric method, according to the steps suggested for the blood- 

 coloring matters. 4 



Biliverdin, CieHis^CU or C32H36N4Cg. This body, which is formed 

 by the oxidation of bilirubin, occurs in the bile of many animals, in 

 vomited matter, in the placenta of the bitch (?), in the shells of birds' 



1 Heinsius and Campbell, Pfliiger's Arch., 4; Stokvis, Centralbl. f. med. Wis- 

 sensch., 1872, 785; ibid., 1873, 211 and 449; Jaffe, ibid., 1868; Maly, Wien. Sitzungs- 

 ber., 59. 



2 Zeitschr. f. physiol. Chem., 47. 

 Ibid., 59. 



4 See also Herzfeld, Zeitschr. f. physiol. Chem., 77 and 78. 



