On certain points connected with diabetes : delivered at the Royal College of Physicians / by F.W. Pavy.

  • Frederick William Pavy
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: On certain points connected with diabetes : delivered at the Royal College of Physicians / by F.W. Pavy. 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.

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    the formation of sugar, or of a substance that, like it, exerts a reducing action on the copper test, from some other constituent of the urine, whether colour- ing matter or not, carried down with the lead pre- cipitate. Schunk has pointed out, and I can confirm his statement, that boiling hydrochloric acid certainly appears to act in this way. No exception, however, can be taken to the use of sulphuretted hydrogen ; and with this agent a better, because a purer and more colourless, product is obtained. The precipitate with a little water is placed in a suitable apparatus and a stream of sulphuretted hydrogen passed through till decomposition is thoroughly effected, which may be known by the uniform production of intense black sulphide. With a moderate amount of precipitate a few hours will suffice for the purpose. Filtration is next performed, and the excess of sulphuretted hydrogen expelled by heat. The liquid is then brought down to a small bulk, either over the water bath or in the vacuum of an air-pump. I have here mentioned the main points requiring to be referred to. Full details upon the whole sub- ject I gave in a communication On the Recognition of Sugar in Healthy Urine, inserted in the ' Guy's Hospital Reports' for 1876. If we take the product that has been obtained, and test it with the copper test a neat reaction is produced [result shown]. Such is the result that we notice, but the question arises—Is this result to be taken as conclusive evidence that sugar is present ? There can be no fallacy arising through the presence of lithic acid, which exerts a certain degree of re- ducing effect with the copper solution, for this prin-