1867.] 



Extractive Matters of Urine. — -Part I. 



79 



ing their chemical or physical properties. The experiments of Alois 

 Martin *, the results of which were made known soon after those of Heller, 

 led to the same conclusion, viz., that in some diseases the urine on being 

 mixed with mineral acids deposits in considerable quantity a dark-coloured 

 sediment, consisting of two colouring-matters, one of which is blue, the 

 other red. Regarding the former, which he calls urokyanine^ Martin 

 states that it is insoluble in water and caustic alkalies, but soluble in alco- 

 hol and ether, that it is dissolved by concentrated sulphuric acid, the solu- 

 tion becoming blue on dilution with water, and that when heated it yields 

 violet-coloured fumes like those of iodine. Although these observations, 

 however incomplete, were no doubt correct, very little importance was 

 attached to them by chemists in general, and their accuracy was even 

 questioned by some. Berzelius characterizes Heller's statements as un- 

 certain and unsatisfactory. Lehmann says, " Heller's experiments were 

 so incomplete that the very existence of such pigments as uroxanthine and 

 urorhodine is still doubtful." Golding Bird was of opinion that Heller had 

 described as crystals of uroglaucine uric acid merely tinted by the changed 

 colouring-matter, and he adds, *'This error is an important one, and 

 throws much doubt on many of his conclusions." When a few very 

 simple experiments would have sufficed to prove the accuracy of the obser- 

 vations referred to, or to have shown in what respect they were erroneous, 

 such criticisms as these can hardly be considered fair ; and I think that 

 Heller's claims as the discoverer of the artificial formation from urine of a 

 blue and a red colouring-matter of definite character cannot be contested. 

 Golding Bird certainly claims to have been the first to observe the forma- 

 tion of a red or pink colouring-matter, supposed by him to be identical 

 with that of the so-called pink deposits, by the action of hydrochloric acid 

 on healthy urine ; but, without deciding the question of priority, I will 

 merely remark that his experiments must have been of a superficial 

 character, or the simultaneous formation of a blue colouring-matter would 

 hardly have escaped his notice. On the other hand, when it is considered 

 that the blue pigment occasionally deposited from urine had, as mentioned 

 above, been proved to be indigo-blue by several of the earlier observers, 

 and that at the tim-C when Heller and Martin gave an account of their 

 experiments the properties and products of decomposition of this colouring- 

 matter were well known, it is surprising that these chemists should not 

 have suspected the identity of uroglaucine, urokyanine, and indigo-blue. 

 A few comparative experiments would have proved their identity, and have 

 thus led to the discovery of one of the most important and interesting 

 facts connected with the chemistry of this subject. How far Heller was 

 from understanding the true nature of his blue colouring-matter will be 

 seen by the following extract from his last memoir. He says, "If a 

 pale yellow urine, rich in uroxanthine, either originally alkaline or alkaline 

 through standing, be kept in a well-corked flask, the violet-coloured sub- 

 * Heller's Archiv, 1846, S. 191, 287. 



