BlLIRUBINE. 77 



will, after extraction of the bilifuscine, also yield bili- 

 rubine, but in very small quantity only. 



3. Human bile or ox bile will by putrefaction deposit 

 bilirubine. See Bile, 19. 



4. Saturate some very dilute aqueous solution of 

 ammonia witli bilirubine in excess, and filter quickly. 

 In this solution nitrate of silver produces a precipitate 

 of neutral monohydrated cholophgeinate of silver 

 C 9 H 10 AgN0 3 . In the same solution chlorides of 

 baryum and calcium produce red precipitates of the 

 half-acid salts, sesqui-cholophseinates, which contain 

 three atoms of cholophseine, two atoms of water, and 

 one (didynamic) atom of metal, yielding the formula 

 C 27 H 29 M''N 3 8 . 



5. Dissolve some cholophseine in excess of am- 

 monia. To this solution add chloride of calcium or 

 baryum, and observe the formation of dark red precipi- 

 tates of the neutral salts of the formula C 18 H 20 MISr 2 6 . 



6. Dissolve some bilirubine in caustic or carbonated 

 alkali, and expose to the air for some days, frequently 

 shaking the solution with air. Observe that the red 

 solution becomes purely green. Then precipitate by 

 hydrochloric acid, wash the green flakes by decanta- 

 tion, and dissolve in absolute alcohol. The latter on 

 evaporation will leave pure biliverdine C 8 H 9 N0 2 . 



7. Add to an ammoniacal solution of cholophseine 

 concentrated nitric acid drop by drop until a blue 

 precipitate is formed. Isolate quickly by filtration, 

 and after washing dissolve in alcohol. This blue solu* 

 tion of cholocyanin has the following spectrum : 



