On urobilin. Part II, The per-centage composition of urobilin / by F. Gowland Hopkins and Archibald E. Garrod.

  • Frederick Hopkins
Date:
[1898?]
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Licence: Public Domain Mark

Credit: On urobilin. Part II, The per-centage composition of urobilin / by F. Gowland Hopkins and Archibald E. Garrod. Source: Wellcome Collection.

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    to a formula showing any simple relationship to that accepted for bilirubin, and until experiment has shown by what chemical steps a product strictly agreeing in its general characters with natural urobilin can be prepared from bile pigment it is undesirable to pursue the question of its constitution. We may be permitted to say that we entered upon the analysis of urobilin obtained from natural sources in the hope that our results might help to place upon a firmer foundation the belief, which has prevailed since the publication of Maly’s results, that there exists a sumple relationship between that pigment and bilirubin. This hope has not been justified by the results, and we are convinced that the relationship is by no means so simple as has been supposed. The change from bilirubin to urobilin cannot be a mere question of reduction and hydrolysis, but must necessarily be attended by a removal of nitrogen; of this our analyses leave no doubt whatever. On the other hand we cannot doubt that the one pigment is actually derived from the other, a conclusion which evidence of other kinds appears to us to render unavoidable. It is a well-known fact that in health the bile pigment which enters the duodenum disappears, as such, before the intestinal contents are expelled, and in its place we find in the feces urobilin and its chromogen. When, as in certain cases of typhoid fever, the bile pigment is found in abundance in the feces, the urobilin is greatly diminished in quantity or altogether wanting. When the flow of bile into the intestine is arrested urobilin and its chromogen disappear from the feces, to reappear when the patency of the bile ducts is re-established. Friedrich Miiller! has further shown that when bile is introduced into the stomach of a patient with complete biliary obstruction and whose feeces are urobilin-free, urobilin appears in the stools. It therefore remains to seek further evidence as to the series of chemical changes which the bile-pigment undergoes in the alimentary canal, and especially on the lines of those experimenters who have succeeded in preparing an artificial product resembling urobilin by the action of intestinal micro-organisms upon bilirubin. Of the product so obtained as well as of various other artificial urobilin-like products we hope to speak in a third instalment of this paper. 1 Schlesische Gesellsch, f. vaterland Kultur, Jan. 1892,
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