807 



Physiology. - '"The idcntijication of traces of bilirubin in albu- 

 minous jluuUy liy Prof. A, A. Humans van den Bergh 

 and J. J. DE i;A Fontaine Schluiter. (Communicated by 

 Prof. H. J. Hamburger). 



Several investigators have tried to demonstrate the presence of 

 slight quantities of bilirubin in albuminous substances, for instance 

 in normal human bloodserum. Most of them did this by adding 

 various oxidizing substances, either directly (o the serum or to an 

 alcoholic extract of the latter. The tirst oxidation-stages of bilirubin 

 having a green or a blue colour, the presence of bilirubin was 

 regarded as established if an addition of these oxidizing substances 

 gave rise to a green or a blue colour (Obermaijer and Popper, Steiger, 

 Gilbert^) and others). Auche^) employed a much more reliable 

 method based on the fact that bilirubin, in alkalic solution in the 

 presence of oxide of zinc, is changed, by careful oxidation with 

 iodine, into a substance with a characteristic spectrum. This reaction 

 had already been described by Stokvis, but Auché, who mentions 

 Stokvis' Avork, owns the merit of having stated accurately the con- 

 ditions required if the reaction is to take place with absolute cer- 

 tainty, so that it may be used to demonstrate the presence of bilirubin. 



undoubtedly the reaction of Stokvis- Auche can be used with success. 

 Only the spectrum-line is very slight in the case of the small amounts 

 of bilirubin dealt with in this treatise : if the presence of bilirubin 

 is to be demonstrated in normal human serum by means of this 

 method, the layer of fluid intended for spectroscopic investigation is 

 to have a thickness of ten centimetres. And even then the result is 

 not always a positive one. For quantitative determinations this method 

 cannot be used. 



BiFFi extracted the serum at once with chloroform and carried 

 out his reactions with this ^). 



The reaction of Ehrlich has supplied us with an excellent means 

 of tracing bilirubin in bloodserum and other albuminous fluids and 

 of determining it quantitatively "). The ciiaracteristic difference in 

 colour between an alkaline and an acid medium increases its relia- 

 bility, whilst the reaction is an extremely sensitive one. It must, 



1) Obermaijer u. Pcppf:R. Wiener Klin. Wochenschr. 1908. 



Steiger. Dissert. Zurich 1911. 



Gilbert. See for his works the bibliography in: Cliniquc médicde 1910/1911, 



~) AucHÉ. Compt. rend. Acad. d. Sciences 1908. 



8) BiFFi. Folia Haematolog. 1906 III. 189. 



+) Humans van den Bergh and Snapper. Deulsch. Arch. f. klin. Med. 1913. 



