On the cause of the non-precipitation of oxide of copper in testing certain cases of diabetic urine / by T. Lauder Brunton.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
[1880?]
Catalogue details

Licence: Public Domain Mark

Credit: On the cause of the non-precipitation of oxide of copper in testing certain cases of diabetic urine / by T. Lauder Brunton. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    healthy persons in large quantities, for normal urine will often dissolve ten times as much cuprous oxide as it can itself form by reduction. It is only necessary to add to normal urine measured quantities ot diabetic urine, or weighed quantities of sugar, in order to convince one s self that even when the amount of sugar is increased by one-half per cent., and sometimes even by 1 per cent., Trommer’s test gives a negative result, if one judges by the precipitation of the cuprous oxide. This has hitherto always been the case, and the numerous researches which have been made on the excretion of sugar by the kidneys, after feed- ing with sugar or its injection into the blood, are therefore . to some extent valueless, especially as the experiments have gene- rally been made with dogs, the urine of which animals contaius enormous quantities of the substances which dissolve cuprous oxide. Of one of these substances we can speak more definitely. It is, according to Winogradoff, creatinine, an alkaline solution of which.retains in solution the cuprous oxide which has been reduced by means of sugar in such a way that it is not precipitated by dilute sulphuric acid. Creatinine, however, is in all probability not the only substance concerned iu preventing the precipitation of cuprous oxide in normal urine. In diabetes these substances which precipitate are generally absent, and Winogradoff found in fact, that the excretion of creatinine in many cases of diabetes was diminished or completely arrested. But this is not always the case, for there are some kinds of diabetic urine which allow only a part of the cuprous oxide to be precipitated, and retain another part in solution. Indeed, there are some where the precipitation of cuprous oxide is absent even when the urine contaius x to 1 \ per cent, of sugar. We can readily see that in such cases, when the amount of sugar sinks under 1 per cent., Trommer's test would apparently indicate the entire absence of sugar. “ After many years’ observation,” says Kiihne, “I am inclined to suspect that those substances which retain cuprous oxide in solution are found in those cases of diabetes which run a slow course, and in which, with the exception of the high percentage amount of sugar in the urine, the symptoms of diabetes are abseut or only slightly marked, and the urine retains its normal depth of colour.” In the most typical cases, on the other hand, with excessive secretion of a very pale urine, with a dry skin, and frequently with the formation of cataract, these substances are either entirely absent from the urine or present iu very small quantities. Such cases must, therefore, in addition to the increased formation of sugar, be complicated with another pathological process, which consists in the non-formation or non-excretion of these substances It would be desirable to investigate how far this last process is