On various modes of testing for albumen and sugar in the urine : two lectures / by George Johnson.

  • George Johnson
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: On various modes of testing for albumen and sugar in the urine : two lectures / by George Johnson. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    boiled with caustic potash, forms a most delicate test for glucose. I added some picric acid solution to a boiling specimen of diabetic urine, which had been previously mixed with liquor potassse, and found, to my surprise, that the liquid at once assumed an intensely dark colour. I was not then aware of the fact that this reaction of picric acid with grape- sugar had been obseiwed by Braun, a German chemist, nearly twenty years ago (‘ Ueber die Um- wandlung der Pikrinsaure in Pikramminsaure, und liber die Nachweisung der Trauben-Zucker.’ C. D. Braun, Zeitschrift fur Chemie, In this paper, it is shown that grape-sugar, when boiled with picric acid and potash, reduces the yellow picric acid to the deep red picramic acid, the depth of colour depending on the amount of sugar present. I am not aware that hitherto any attempt has been made to utilise this as a qualitative clinical test for sugar in the urine, or as a means of accurately estimating the amount of sugar in a saccharine solution. I think, however, that, after having been the subject of much hostile criticism, the value of the test for both purposes has been completely proved and established. I take a fluid drachm of a solution of grape-
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