134 On the Colouring and Extractive Matters of Urine. [Recess^ 



In the preceding review several of the determinations given in Part I. 

 have not been referred to. They are as follows : — 

 Series A, Analyses II., V., VI., VII., VIII. 



E, „ I., III., IV. 



F, „ II., VII. 



Of these A. II. and A. VI. gave numbers corresponding very well with 

 the formula C^^ H^g NO^^, which may be considered to represent a mixture 

 of what may be called the hydrates of urian and urianine, since 



^ 2 H,3 NO,,) = C33 N03,H-C33 H33 NO3,. 

 . A hydrate having the formula Cge H59 NOgQ was once isolated, and its 

 lead compound was submitted to analysis (F. V.) ; but the other was not 

 obtained in my experiments, though Analysis V. Series A gave results 

 agreeing with the formula C33 H^, N02g, which represents a compound of 

 urianine and water. The substance .with which Analysis VII. Series A 

 was made was probably a mixture of oxurianine and glucose, examples of 

 which occurred frequently in the course of my experiments, as I have 

 before explained. The Analyses I. Series E and II. Series F are the only 

 determinations of importance which admit of no explanation, unless it be 

 assumed that considerable errors were committed in making them. 



I maintain, then, that, with the exceptions just named, the numerical re- 

 sults obtained in my examination of the composition of these bodies may be 

 explained by adopting the views which I have set forth, views which, I 

 venture to say, have at least the merit of simplicity to recommend them. 

 Whether they are correct or not I should, however, despair of arriving any 

 nearer the truth by still further multiplying experiments of the kind I have 

 described, and I therefore have brought this portion of the investigation to 

 a close. 



The striking analogy subsisting between the extractive matters of urine 

 and the series of bodies of which indican forms the first member is a point 

 of some interest, to which I shall have again occasion to refer. The rela- 

 tion in which urian and urianine stand to one another is, in my opinion, 

 similar to the one which has been found to exist between indican and indi- 

 CRuine. Then, again, both urianine and indicanine take up oxygen,' and 

 are converted into oxuiianine and oxindicanine, bodies which, in their 

 physical properties, resemble those from which they are derived. It is 

 indeed not impossible that oxindicanine may be actually converted by a very 

 simple process into oxurianine, as will be evident from the following 

 equation : — 



Oxindicanine. Oxurianine. 

 C,o H,3 NO3, + 4 HO = C3, II,, NO3, + 2 CO,. 

 Processes such as the one represented by this equation are constantly 

 going on in the body, and it is therefore quite possible that the indican 

 originally existing in the blood or tissues may be decomposed, and appear 

 in the urine as ordinary extractive matter. Indeed the same process may 

 take place in the urine itself as a result of fermentation and oxidation^ 



