Experimental investigation of the reactions of various copper salts with grape sugar : some new and reliable tests for sugar in urine / by George Hay, M.D.

  • Hay, George, M.D.
Date:
[1885?]
Catalogue details

Licence: Public Domain Mark

Credit: Experimental investigation of the reactions of various copper salts with grape sugar : some new and reliable tests for sugar in urine / by George Hay, M.D. 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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    [RErRINT FROM THERAPEUTIC GAZETTE, MARCH, 1885.] Experimental Investigation of the Reactions of Various Copper Salts with Grape Sugar —Some New and Reliable Tests for Sugar in Urine. BY GEORGE HAY, M. D. WITH the object in view of finding out experimentally some ready method of ascertaining beyond a doubt the presence of grape sugar in the urine, I have for many months been making experiments. When the results of these experiments are looked into it will be seen that I have adhered to one systematic method of investigation, that be- ing, in my opinion, the only way to arrive at satisfactory conclusions. Some years ago I pointed out,in the Phil a'.'Medical Times, The Fallacy of Trommer's Test, the precise dates being July 21st, 1877, and October 27th, 1877. Since that time my opinions regarding Trommer's test have not altered in the least degree, and I am now more than ever con- vinced that Trommer's test is utterly unreli- able as usually applied, and is, in point of fact, no test at all. When applied to a solu- tion of grape sugar in pure water, Trommer's test will answer very well, but wflen applied to diabetic urine, the results are far from being satisfactory. Sugar will apparently be found when none is present, and, conversely, no sugar will be found when it is really present. The importance of knowing the presence or absence of sugar in the urine is too manifest to require any remark. I shall therefore without further introduction detail my experi- ments as shortly and concisely as may be done'consistently with being intelligible, and I shall avoid all attempts at theorizing, although that is a much more easy thing than real experimentation. I shall detail the re- sults in the exact order in which I made the experiments under the headings of the various copper salts. § ISt. CHLORIDE OF COPPER. a. Chloride of copper, gr. j; dissolve in water f. 3 ij. in a test tube. Add solution of caustic potash in excess. Precipitates blue hydrate—protoxide of copper. Heat. Pre- cipitate becomes black protoxide. b. Chloride of copper, gr. j., dissolve in water f. 3 ij. Add aqueous solution of grape sugar gr. \, then add caustic potash in excess. —an intense blue solution. Heat. Solution becomes yellow, afterwards there forms a beautiful red precipitate of suboxide of cop- per. Heating continued—precipitate Decomes a dirty brick red, unchanged by continued heating. c. Chloride of copper, grs. ij., in solution: add to urine f. 3 ij. containing grape sugar gr. i—greenish-grey precipitate. Add caustic potash in excess—greenish-grey precipitate becomes dissolved to intensely blue fluid. Heat. Fluid becomes first nearly black. Afterwards, fluid red by transmitted light. Upon long continued heating red color disap- pears and fluid contains yellowish-red precipi- tate of suboxide of copper. Let settle. Re- duction and separation very slow. d. Chloride of copper, grs. iv., in solution. Add to urine f. 3 iv. containing grape sugar, gr. f. Greenish-grey precipitate. Heat. Fil- ter. Divide filtrate into two equal parts. To one part add caustic potash in excess—blue solution. Heat. Same changes occur as in c., but much more rapidly, and precipitate separ- ates sooner and is of a distinctly orange color. To the other portion of filtrate add a little Rochelle salt, then potash in excess—blue solution. Heat. Precipitation and reduction very much retarded by presence of Rochelle salt and the precipitate not nearly so charac- teristic as when the Rochelle is omitted. Takes several hours to precipitate. § 2nd. SULPHATE OF COPPER. a. Sulphate of copper saturated solution, gtt. xv. Water f. 3 ij. Add potash in excess —precipitate blue hydrated oxide of copper. Heat. Precipitate becomes black protoxide. b. Sulphate of copper saturated solution, gtt. xv. Water f. 3 ij. Solution of grape sugar, gr. \. Add potash in excess—blue solution.