A contribution to the study of the yellow colouring matter of the urine / by Archibald E. Garrod ; [communicated by Sir Alfred B. Garrod].

  • Garrod, Archibald Edward, 1857-1936.
Date:
[1894]
Catalogue details

Licence: Public Domain Mark

Credit: A contribution to the study of the yellow colouring matter of the urine / by Archibald E. Garrod ; [communicated by Sir Alfred B. Garrod]. 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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    C. Tichborne* (1862) threw down most of the colouring matter of a large quantity of concentrated urine upon a basic copper precipi- tate, and extracted the pigment from the precipitate by means of cold dilute sulphuric acid and alcohol. In this way he obtained a solution which, on evaporation, left a brown residue, very hygroscopic and smelling of stale urine, solutions of which yielded, according to the degree of concentration, the various tints of normal urines. The pigment was soluble to almost any extent in water, was in- soluble in ether, sparingly soluble in absolute alcohol, and more readily in rectified spirit. It was precipitated from solution by basic lead acetate. The results of elementary analysis led Tichborne to think that it was derived from hippuric acid by the subtraction of water, the per- centage composition obtained being C, 67'80 ; H, 4 23 ; 1ST, 8'56; 0, 19-41. It is extremely doubtful whether combustion analyses of such sub- stances are calculated to materially advance our knowledge, in the absence of any of the ordinary guarantees of the purity of the sub- stance analysed; and so simple a process as that employed by Tich- borne could only be expected to yield a product of a moderate degree of purity. Thudichumf (1864) obtained from normal urine by a variety of processes a substance to which he gave the name of ui’ochrome, and his researches which have extended over a long period form the most elaborate contribution yet made to the subject. In the second edition of his work on the urine, J in which his later researches are embodied, he gives four methods for the isolation of urochrome in which phosphomolybdic acid and the neutral and basic lead acetates are employed as precipitants, and sulphuric acid, sulph- uretted hydrogen, &c., for the extraction of the pigment from the pre- cipitates. Great pains were taken to obtain the pigment in the highest attainable degree of purity. Thudichum describes urochrome as forming yellow crusts when its solutions are evaporated, as dissolving very readily in water, fairly readily in ether, and least easily in alcohol. It was precipitated from its solutions by lead acetate, silver nitrate, acetate and nitrate of mercury, &c. On heating with mineral acids the aqueous solution became red, and resinous flakes were thrown down from which three definite substances could be obtained, which were minutely studied, and sub- jected to ultimate analysis. These substances were a red pigment, * * Chemical News,’ 18G2, vol. 5, p. 171. t Loo. cit, I ‘ Pathology of the Urine,’ 2nd Edit., 1877, p. 217.