390 



Dr. C. A. MacMunn. 



found. Now as this pigment occurs in the skin of Mullus surmulehis 

 and other fishes, it is not impossible that in some fishes the liver may 

 function in a similar manner to that of Invertebrates, and serve as a 

 pigment-storing organ for surface coloration. 



Detection of Bilirubin, Sfc, in Exudations. — The peculiar series of 

 bands, and the way in which they appear and disappear when solu- 

 tions of the bile-pigments are treated with nitric acid, serve as accu- 

 rately for their detection as can be wished. In a former paper I 

 showed the effect of chlorine in traces on such a solution, and the 

 description of the spectrum thereby produced applies to G-melin's 

 reaction. A band appears before D, then one after D, and one at F ; 

 the second one fades away first, followed by that before D, and that at 

 F is left. This finally also disappears. No other animal colouring- 

 matter behaves in this manner, hence this test is conclusive. In apply- 

 ing it the colouring- matters should, if possible, be got into solution in 

 alcohol or chloroform, and the nitric acid added to the solution. Care 

 is necessary in the case of the alcoholic solution, and it should be 

 diluted sufficiently with water before adding the acid. 



Origin of the Colouring -matters of Bile. — The discrepancies in the 

 statements of physiological chemists as to the identity of hgematoidin 

 and bilirubin probably arose from the fact that deposits of blood 

 colouring-matter, undergoing all stages of decomposition, have been 

 included under that name. The evidence for the identity is given by 

 Hoppe-Seyler in his " Physiologische Chemie " (pp. 311 — 313). I 

 have already shown that the same pigments can be formed from hsemo- 

 globin and bilirubin, but an actual proof of the transformation of 

 haBinoglobin into biliverdin has not, so far as I know, been brought 

 forward until now. 



The liquid* in which the biliverdin was detected had been removed 

 by tapping from the tunica vaginalis testis of a case of chronic 

 epididymitis. Six months before the specimen was removed the sac 

 had been transfixed by a needle in the hope of causing absorption, but 

 without effect ; three months later it was punctured with a trochar 

 and canula, and about two ounces of blackish bloody serum drawn off, 

 but the fluid again accumulated, and at the end of three months tap- 

 ping was again performed. The liquid removed on this occasion was 

 a dark bluish-green. Since it was albuminous, a method had to be 

 adopted, before applying the spectroscopic test, which would coagulate 

 the albumen without altering the colouring- matter, and then extract 

 the latter. The liquid showed, however, without any treatment, the 

 presence of a hEemoglobin derivative, which was proved by appropriate 

 tests to be a body intermediate between metheemoglobin and haematin ; 

 it also absorbed strongly the violet end of the spectrum. The albumen 



* I have to thank Dr. Carter, of Birmingham, for this specimen. 



