The Croonian lectures 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: The Croonian lectures 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 Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    the formation of sugar, or of a substance that, Kke 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 eflPected, 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 ' Gruy'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-