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

Alfred Henry Allen

Date:: 1895

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

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$POTASSIUM INDOXYL-SULPJI ATE, Urinary Indigogens. Normal urine contains traces of the potassium salt of indoxyl-sulphuric acid, CsHi^N.SO4H. This body is derived primarily from indole, C8H7N, which by oxidation yields indoxyl, C8H5(NH).OH. By reaction with the elements of sulphuric acid this is converted into an ethereal salt, the potassium com- pound of Vvdiich is the substance in question. Potassium Indoxyl-sulphate, C8H(jN.S04K, has received the unfortunate name of “ urinary indican, from a supposed identity with plant-in dican, the glucoside from which indigo is obtained. The only similarity between the two bodies is that both yield indigo-blue as one of the products of their decom- position.^ Potassium indoxyl-sulphate crystallises from hot alcohol in colourless lustrous tables, readily soluble in water but only sparingly in cold alcohol. When boiled with dilute acid it is decomposed into indoxyl and acid potassium sulphate, but is not attacked by alkalies. When the crystals are heated, indigoti]i (indigo-blue) sublimes, and the same substance is found quanti- tatively when the acidulated solution is warmed with ferric chloride. For the detection of indoxyl-sulphuric acid in urine, Jaffe {Pjiilgers Archiv., iii. 448) first separates any albumin by boiling the liquid, and treats the filtrate with an equal measure of hydrochloric acid. A dilute solution of bleaching powder is then cautiously added, until the blue colour no longer increases. On ’ Iiidoxyl-sulpliui'ic acid is described by some writers as indoxyl- s u 1 p h 0 n i c acid. The latter name would be applicable to a body of the constitution CjH4(S03H)(NH).0II. This would be isomeric with indoxyl- sulphuric acid, and would not exhibit the readiness of the latter in hydro- lysing into sulphuric acid and indoxyl (page 6). ® Decomposing urine occasionally forms a bluish-red pellicle, and ultimately deposits microscopic crystals of indigo-blue. A calculus of the same nature has been described.$