PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



January 11, 1866, 



Lieiitenant-General SABINE, Presidentj in the Chair* 



The following communication was read i — 



On the Colouring and Extractive Matters of Urine. — Part I.'* 

 By Edward Schunck, F.R.S. Received June 29, 1865* 

 (Abstract.) 



Notwithstanding the labour bestowed by many eminent men on the 

 chemistry of urine during the last sixty years, there are portions of the 

 subject of which we have but a very imperfect knowledge. Of all the 

 properties of urine, none is more obvious, even to the ordinary observer, 

 than its colour ; and yet very little is known concerning the chemical na- 

 ture of the substances to which its colour is due. Our ignorance in this 

 respect may be ascribed to various causes, among which may be mentioned 

 the extremely minute quantities of these substances occurring in the se- 

 cretion, the facility with which some of them are decomposed^ their che- 

 mical and physical properties (which present to our notice very little that 

 is characteristic), and, lastly, the little interest which they possess for the 

 chemist, notwithstanding their importance from a physiological and patho- 

 logical point of view. According to the author, the colouring-matters 

 peculiar to urine may be divided into three classes, viz. — 



1st. Those which are only found occasionally in it^ in consequence 

 either of disease or of some abnormal state of the system. 



2udly. Those which are produced by spontaneous decomposition, or by 

 the action of reagents on substances, either coloured or colourless, pre- 

 existing in the urine. 



3rdly. The colouring-matter or matters occurring in normal urine, and 

 to which its usual colour is due. 



VOL,. XV. B 



