242 BILIRUBIK 



above all in chloroform. From its solution in the latter it may be 

 separated out by extremely slow evaporation of the solvent in a 

 crystalline form as rhombic plates or prisms. The general shape of 

 these is shown above in Fig. 40; but as obtained from solution in 

 either carbon-disulphide or chloroform the crystals usually exhibit 

 somewhat blunt ends and slightly convex surfaces as first pointed 



FIG. 41. BILIRUBIN CRYSTALLISED FROM CARBON-PISULPHIDE. (Krukenberg.) 



out by Staedeler. As ordinarily prepared it is an amorphous powder 

 of the colour of sulphide of antimony. It readily forms compounds 

 with bases, e.g. sodium, barium and calcium, the latter providing a 

 convenient means for the separation of bilirubin from bile, urine 

 or other dilute solution. 



Preparation, (i) When gall-stones are not available bile may be 

 treated as follows 1 . The bile is slightly diluted with water, some 

 lime-water is added (avoiding excess) and after thorough mixture, 

 as by shaking, a current of carbon dioxide is passed to convert all 

 the excess lime into carbonate. The precipitate thus formed contains 

 the bilirubin as a calcium compound. This is then collected on a 

 filter, washed with water and, after suspension in a little water, 

 decomposed by the addition of a slight excess of acetic or hydro- 

 chloric acid. By this means the bilirubin is set free and may now 

 be extracted by shaking with an excess of chloroform. The chloroform 

 solution is separated by decantation, and evaporated to a small bulk ; 

 the bilirubin may then finally be precipitated by an excess of alcohol. 

 The amount thus obtained is not quantitatively accurate, since all the 

 bilirubin is not precipitated by the lime at the outset and there is 

 a further loss during the subsequent operations, (ii) Since as already 



1 Based on Huppert, Arch. d. Heilk. Bd. vin. (1867), S. 345, 476. See Hoppe- 

 Seyler, Hdbch. d. physiol.-path. chem. Anal 1883, S. 250. Cf. Hilger, Arch. d. 

 Pharm. (3), Bd. vi. (1875), S. 385. 



