322 TRIBROMOBILIRUBIN. BILIVERDIN. [BOOK II. 



The supposition that the coloured bodies obtained under the action 

 of bromine were, like those obtained with a mixture of nitric and 

 nitrous acids, products of oxidation, was disproved by the examination 

 of the green biliverdin-like body which is the first product of the 

 action of bromine. It was at once apparent that this body possessed 

 a green colour because of its being a mixture of undecomposed 

 bilirubin and of a beautiful blue substance. This body was prepared 

 in various ways and was found to have an uniform composition, 

 represented by the formula C 32 H 33 Br 3 N 4 6 . According to Maly the 

 reaction in which it is formed may be represented thus : 



C 32 H 36 N 4 O 6 + 3Br 2 = C 32 H 33 Br 3 N 4 6 + 3HBr. 



Bilirubin. Tribromobilirubin. 



Tribromobilirubin is insoluble in water, readily soluble in alcohol 

 and ether, its solutions in which possess a dark blue colour. The 

 addition of pure acid renders the alcoholic solution more intensely 

 blue than before ; this deep blue colour is characteristic of solutions 

 in acetic and glacial acetic acid. Alkaline solutions readily dissolve 

 the body and acquire a violet colour. When boiled with sodium 

 carbonate a green solution is obtained. 



The violet alkaline solutions of bromobilirubin, made with the 

 aid of alkaline hydrates and carbonates, at first assume a blue colour 

 when acids are added to them. After some time, however, when 

 acids are added, the colour changes to a pure green. Chlorine readily 

 bleaches the compound. 



By the action of sodium amalgam, tribromobilirubin is converted 

 into hydrobilirubiri. When digested with solution of caustic soda, 

 dilute sulphuric acid throws down a green body which appears to 

 consist of biliverdin. 



Biliverdin C 32 H 36 N 4 8 . 



To the colouring 1 matter which imparts a green 

 Occurrence. , , , , ., ~ , j ,1 i i 



colour to the bile ot the ox, sheep and other herbivorous 



animals, the term biliverdin was applied by Berzelius, and it is 

 usually assumed, probably correctly, that this body is identical with 

 the biliverdin which results from the action of various oxidising 

 agents on bilirubin. The strict scientific proof of this identity 

 is, however, not forthcoming, no method having as yet been devised 

 for the separation of pure biliverdin from the bile. 



Biliverdin is doubtless the colouring matter found in association 

 with bilirubin in the placenta of bitches ; it likewise may be found 

 in vomited matters and in the contents of the small intestine. 

 Biliverdin is, occasionally, a constituent of gall-stones. It is said 

 sometimes to occur in jaundiced urine ; its presence in urine which 

 has been exposed to the air affords, however, no proof of its having 

 been present in the fresh secretion. 



