1867.] 



Ea-iraciive Matters of Urine. —V&Yt I. 



81 



priving the latter of the greatest part of the ordinary extractive matter by- 

 precipitation with basic acetate of lead, then adding ammonia to the 

 filtered liquid, and acting on the precipitate produced by ammonia with 

 sulphuric or hydrochloric acid, I succeeded in almost every instance in ob- 

 taining a small quantity of a colouring-matter, which I had no difficulty in 

 identifying as indigo-blue. The cases in which this did not occur were so 

 few and exceptional that I was led to conclude that indican, or some sub- 

 stance closely resembling it, is a normal constituent of healthy urine, and 

 that it is only the presence of an excess of this, just as of any other of its 

 usual constituents, that can be considered a symptom of disease. The 

 blue colouring-matter was generally accompanied by another, which dis- 

 solved in alcohol with a fine purple colour, and which I consider to be 

 identical with Heller's urorhodine. As the indican of plants always yields 

 by decomposition indigo-red as well as indigo-blue, I think it not impro- 

 bable that this red pigment from urine may consist of indigo-red ; but from 

 the difficulty experienced in purifying it, and the very minute quantities 

 which, are obtained, this cannot easily be proved. The urine of the horse 

 and the cow yielded the same colouring-matters even in greater abundance 

 than human urine. My experiments have been confirmed by Carter* and 

 others ; and it is now, I believe, generally admitted that they afford a 

 means of explaining the formation of the abnormal colouring-matters of 

 the urine, and may even throw some light on the processes of decomposi- 

 tion which the proteine substances undergo in the system. In order to 

 prove the complete identity of Heller's uroglaucine with indigo-blue, 

 Kletzinsky f prepared a large quantity of uroglaucine, and ascertained that 

 its properties and composition are those of indigo-blue, and he accordingly 

 ascribes to Heller the discovery of indigo-blue in urine. I believe, how- 

 ever, that Heller's claims on this field of research cannot be allowed to 

 extend so far. What I think must be conceded to him is, as I stated 

 above, the discovery of a mode of obtaining a blue and a red colouring- 

 matter from urine by artificial m.eans. 



The formation of brown colouring-matters by the action of acids on 

 urine was first observed by Proust |:. Having evaporated fresh urine to a 

 syrup, in order to separate the greatest part of its salts, he added concen- 

 trated sulphuric acid to it, and then submitted the liquid to distillation. 

 The distillate contained a large quantity of acetic acid and a little benzoic 

 acid, while the liquid deposited a brown mass of the consistence of pitch, 

 which increased in quantity as the distillation proceeded. This mass con- 

 sisted chiefly of a resinous body, which he found to be insoluble in water, 

 but easily soluble in alcohol and alkaline liquids. In consistence, colour, 

 and smell it resembled castoreum, and it had a sharp, bitter taste like that 

 of arum-root. Proust believed it to be the substance to which the colour 



"'^ Edinburgh Medical Journal, August 1859. 



t Sclimidt's Jahrbiicher d. Mcdicin, B. civ, S. 36, 



\ Annalc« do Chimie, t. sxxvi. p. 274 ; and Annales de Chira. ct de Pliys. t. xiv. p. 262. 



