Chemistry of urine : a practical guide to the analytical examination of diabetic albuminous, and gouty urine / Alfred H. Allen.

  • Alfred Henry Allen
Date:
1895
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry of urine : a practical guide to the analytical examination of diabetic albuminous, and gouty urine / Alfred H. Allen. Source: Wellcome Collection.

    90/250 (page 72)
    absolutely no reducing action after clarification by the mercury reagent. This implies that an infinitely large quantity of the filtrate resulting from this treatment could be added to a limited volume of Pavy’s solution without the blue colour of the latter being destroyed. But as the reduction of the mer- curic solution with separation of calomel, and the simultaneous oxidation of the glucose, commences after a few minutes’ ebullition, it is conceivable that when mere traces of sugar are present they might be entirely destroyed at this stage of the process, and that the amount found in the filtrate would be merely that which had survived the treatment.^ Eecognising the objections attaching to any process in which glucose is subjected to the action of a hot solution containing fixed caustic alkali, A11 e i n and Gaud {Jour. Pharm. Chem., [5], xxx. 305 ; and Jour. Chem. Soc., Ixviii. ii. 92) have recently pro- posed to employ a strongly aihmoniacal solution of cupric sulphate for determining sugar. The process has been tried in the author’s laboratory, but the reduction was found to occur so slowly that the method cannot be recommended. Glycerol-Cupric Solutions.—In 1870, J. Lowe suggested the use of glycerin as a substitute for alkaline tartrate in preparing an alkaline cupric solu- tion. He gave a recipe for preparing the solution from cupric sulphate, glycerin, and caustic soda, but j)referred to employ freshly precipitated cupric hydr- oxide instead of the sulphate {Zeits. anal. Chem., x. 452). More recently, a glycerol-cupric solution has been advocated by W. S. Haines (Chicago), who prepares it by dissolving 30 grains of crystallised ^ Experiments made in tlie author’s laboratory, to test this point, showed that the oxidation by mercuric acetate of glucose in very dilute solutions (0’06 to O’lO per cent.) was very imperfect, and that 80 to 90 per cent, of the glucose survived boiling with the mercuric reagent for ten minutes.