

CHAP, iv.] EHRLICH'S REACTION. TRIBROMOBILIRUBIN. 321 



the bilicyanin and choletelin stages of Gmelin's reaction. In 1877 

 Dr MacMunn 1 ^ quite independently of the above researches which 

 were unknown to him, again described with correctness the spectrum 

 of Gmelin's reaction. 



The spectrum of the second stage of Gmelin's reaction is shewn 

 in Plate I, Sp. 3. 



Enriicn's Gmelin's reaction, with slight modifications to be 



reaction. afterwards noticed, is common to biliverdin and other 

 biliary colouring matters. We have now to speak, however, of a 

 reaction, discovered by Professor Ehrlich 2 , which is characteristic 

 of bilirubin and is not exhibited by biliverdin. To a solution of 

 bilirubin in chloroform, is added an equal volume, or twice its 

 volume, of a solution of sulphanilic acid (1 grm. sulphanilic acid, 

 15 c.c. of hydrochloric acid and 0*1 grm. of sodium nitrite dis- 

 solved in distilled water and diluted to 1 litre) and then as much 

 alcohol as is needed to render the solution clear. The liquid, which 

 is of a yellow colour at first, assumes a beautiful red tint. On 

 adding dilute hydrochloric acid, drop by drop, the colour changes 

 first to violet and then to an intense blue. On now carefully 

 pouring into the test-tube a solution of potassium or sodium hydrate, 

 three zones of colour are visible ; near the alkaline solution, where 

 the reaction is commencing, the colour is green; at the surface, where 

 the reaction is still acid, the original blue tint persists, whilst inter- 

 mediate between these two zones is a red, neutral, zone. 



The late Professor Krukenberg published a full account of the 

 spectroscopic characters of Ehrlich' s reaction. The acid azure blue 

 solution exhibits an absorption band between C and E, of which the 

 centre is a little to the violet side of D, and which as the concentra- 

 tion increases extends more and more towards E. For further details 

 the reader is referred to the original memoir 3 . 



The action Both Thudichum 4 and Maly 5 have investigated the 

 n action of bromine on bilirubin. The following account 

 is based on the observations of Maly. When a solution 

 of bromine in chloroform is added very gradually to a solution of 

 bilirubin in chloroform, a play of colours is observed which is 

 precisely similar to that which constitutes Gmelin's reaction, the 

 colours being the same, as well as the order in which they appear. 



1 C. A. MacMunn, ' Studies in Medical Spectroscopy,' Dub.Journ. of Ned. Sc. 1877; 

 see also The Spectroscope in Medicine, by the same author, pp. 160 162. 



2 P. Ehrlich, ' Sulfodiazobenzol, ein Keagens auf Bilirubin,' Centralblatt /. klin. 

 Med., Vol. iv. (1883), p. 721 ; also in Zeitschrift f. anal. Chemie, Vol. xxm. (1883), 

 p. 275. 



3 Dr C. Fr. Krukenberg, 'Das Spectrum der Ehrlich'schen Bilirubinprobe ' in 

 Krukenberg's Chemisette Untersuchungen zur wissenschaftlichen Medicin. Erstes Heft, 

 Jena 1886, p. 77 79. The description is illustrated by drawings of three spectra. 



4 Thudichum, Journ. of the Chemical Society. Ser. n. Vol. xm. p. 389. 



5 B. Maly, 'Untersuchungen iiber die Gallenfarbstoffe,' Sitzungsber. d. k. Wiener 

 Akad. d. Wissenschaft, Vol. LXXII. (1875). A very complete account of this paper is 

 given in Maly's Jahresbericht, Vol. v. (1876), pp. 193198. 



G. 21 



