CHAP. IV.] SPECTRUM OF PETTENKOFER'S REACTION. 



299 



spectrum 



When a solution in which Pettenkofer's reaction 

 been developed is examined spectroscopically, if 

 reaction. 1 - 2 ' 3 tne concentration be great the whole of the violet and 

 blue rays are absorbed and a marked absorption band 

 is seen occupying the interspace between b and E and extending 

 beyond E towards D ; the centre of this band is about A 527 ; a 

 much fainter shade may be seen on the refrangible side of D, the 

 centre of which corresponds approximately to A 585. If, by the 

 addition of alcohol, we dilute the liquid, or if we examine a thinner 

 stratum, as the absorption of the more refrangible end of the 

 spectrum diminishes, a band on the violet side of F is seen, the 

 centre of which corresponds approximately to A 487. It is the 

 two absorption bands, near E and near F which characterise the 

 secretion. See Plate II. (Spectrum 6). 



The products of decomposition and the means of determining 

 glykocholic acid in the bile will be considered in the sequel 



Properties. 



Hyoglykocholic add, C^ 



This acid is characteristic of the bile of the pig, in which it exists in 

 combination with sodium and was first investigated by Gundlach and 

 Strecker 4 and afterwards by Strecker 5 ; by these observers it was desig- 

 nated hyocholic acid 6 . 



Method of Decolourised pig's bile is saturated with crystallised 



separation. sodium sulphate, which precipitates the sodium compound 

 of hyoglykocholic acid. The precipitate is washed with saturated solution 

 of sodium sulphate, dissolved in alcohol, precipitated with ether, and the 

 ethereal precipitate, after solution in water, is treated with hydrochloric 

 acid, which causes the separation of the bile acid. The process may be 

 simplified by directly dissolving to sodium sulphate precipitate in water 

 and adding hydrochloric acid to the solution. 



Hyoglykocholic acid has not been hitherto obtained in 

 the crystalline form ; it is a white resinous body insoluble 

 in water, slightly soluble in ether, but readily soluble in absolute alcohol, 



1 Koschlakoff und J. Bogomolofif, ' Unterschied zwischen der Pettenkofer'schen 

 Gallensaure- und Eiweiss-reaction ' (aus d. klin. Laborat. d. Herrn Prof. Botkin in 

 St Petersburgh). Centralblatt d. med. Wusenxchaft, 1868, p. 529531. This paper 

 gives an accurate description of the spectrum of Pettenkofer's reaction. A second 

 paper by Bogomolofif, ' Ueber die Spectraleigenschaften der Gmelin'schen Reaction 

 der Galle, der Gallensaure Chromogene, und der Pettenkofer'sche Probe' (Centralblatt, 

 1809, p. 529), is full of erroneous statements concerning the spectrum of Pettenkofer's 

 reaction. 



2 J. L. Schenk, 'Die modificirte Pettenkofer'sche Gallenprobe. ' Anat. phytiol. 

 Untersitchungen von J. L. Schenk. Wien, Braumiiller, 1873. Abstracted in Maly's 

 Jahreabericht, Vol. n. (1874), p. 232. 



3 C. A. MacMunn, 'Studies in Medical Spectroscopy. ' Dub. Journ. Med. Science, 

 1877, and The Spectroscope in Medicine, London, 1880, p. 165. 



4 Gundlach und Strecker, ' Untersuchung der Schweinegalle.' Liebig's Annalen, 

 Vol. LXII. (1847), p. 205232. 



5 Strecker, ' Beobachtungen iiber die Galle verschiedener Thiere. ' Annalen, Vol-Lxx. 

 <1849), p. 149197. 



6 From uy, pig, and \o\-n, bile. 



