On urobilin / by Archibald E. Garrod and F. Gowland Hopkins.

  • Archibald Garrod
Date:
[1896]
Catalogue details

Licence: Public Domain Mark

Credit: On urobilin / by Archibald E. Garrod and F. Gowland Hopkins. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    26/42 (page 134)
    tioD, drying of the precipitate upon the filter and extraction with alcohol, we have obtained results practically identical with his. Normal urines so treated yielded weak solutions of urobilin like those obtained by our process, but from very many morbid urines solutions were obtained which showed a much more intense urobilin band, and which, on the addition of hydrochloric acid gradually acquired a red or pink colour, and showed, in addition to the urobilin band, a shading extending towards the red, and terminating in a comparatively narrow band in green. The fact that the extra band agreed in position and breadth with that of urorosein, which also produces a shading of the whole of the green part of the spectrum, suggested that the observed phenomena might be due to the presence of urorosein as an impurity. Urorosein is one of the pink pigments which is produced from colourless chromogens present in urine by the action of mmeral acids. It was first described by Nencki and Sieber^ and has been made the subject of a somewhat exhaustive study by Kosin^ who was enabled to isolate its chromogen in the form of colourless crystals from the urme of horses, in which it is abundantly present. It is greedily extracted from its solutions by amylic alcohol, and is stated by Nencki and Sieber and by Rosin also, to be insoluble in chloroform, or at any rate to be incapable of extraction by chloroform from the urine in which it is developed. This latter fact, which we can completely confirm, seemed at first sight opposed to the view that this pigment is responsible for the extra band in Eichholz's pathological specimens, seeing that the substance which yields the extra band goes into chloroform with the urobilin. We found, however, that in the presence of alcohol chloroform takes up urorosein readily, and that the alcohol may be washed out of the chloroform, leaving the pigment in that solvent. Under such conditions, i.e. in alcohol-free chloroform, the band ^hows a displace- ment towards red, just as the extra band of the Eichholz product does under similar circumstances. . , . , u It was found, moreover, that when a urine rich in the chromogen of urorosein was saturated with ammonium sulphate the cbromogen wa. to a large extent precipitated, and that in the alcoholic solution of the precipitfte thus obtained, from a specimen of urme poor m urobihn, there was developed, on the addition of hydrochloric acid, a pink colour, and a Tpectrum^^^^ of the pathological urobilin of Eichholz, save that the urobilin band was narrow and very faint. 1 Journ. f. vnikt. Chemie [2] xxvi. p. 333. 1882. a Deutsche med. Wochemchrift. xix. p. 51. 1893.