126 



Mr. E. Scliunck 07i the Colouring and 



[RecesSj 



II. On the Colouring and Extractive Matters of Urine.-'^ — Part II. 

 By Edward Schunck, E.R.S. Received June 20, 1866^. 



Before entering on a con^deration of tlie analytical details contained in 

 the first part of this memoir, it will be necessary to determine the exact 

 number of urinary extractive matters, the existence of which I am justified 

 in assuming after having brought the examination of their composition to 

 a close. Berzelius, as I have before stated, inferred from his experiments 

 that human urine contained three distinct extractive matters, one soluble 

 in absolute alcohol, another soluble only in alcohol of sp. gr. 0*833, and a 

 third insoluble in alcohol of all strengths, and only soluble in ¥/ater. A 

 similar conclusion would probably be arrived at by any one perusing the 

 account which I have given of my own experiments without at the same 

 time possessing any information regarding the chemical nature of the com- 

 pounds analyzed. Nevertheless this conclusion would be incorrect, since 

 a fev/ simple experiments suffice to prove that the extractive matter inso- 

 luble in alcohol is not a distinct substance, but invariably contains a quan- 

 tity of alkaline or earthy bases, on the removal of which the organic matter 

 with which they were combined becomes soluble in alcohol, and that the 

 extractive matters peculiar to urine are only two in iium.ber, the first 

 being soluble in ether and alcohol, the second soluble in alcohol only. 

 This inference is quite consistent with the results derived from the analyses 

 of the lead compounds obtained on various occasions from the extractive 

 matter insoluble in alcohol, the details of which have been given in the first 

 part of this memoir. 



A specimen of the extractive matter insoluble in alcohol was prepared 

 in the following manner : — Ordinary urine was mixed with acetate of lead, 

 and the precipitate thereby produced having been separated, basic acetate 

 of lead was added to the liquid, and the second lead precipitate was filtered 

 off, washed, and treated with dilute sulphuric acid. The excess of the 

 latter was removed by means of carbonate of lead, and the filtered liquid 

 was evaporated to a syrup, which was treated with alcohol. The latter 

 left a portion of the syrup undissolved ; and this portion, after being washed 

 with alcohol, was again dissolved in v/ater and sulphuretted hydrogen was 

 passed through the solution, which, after being filtered from the precipitated 

 sulphide of lead, was treated with peroxide of mercury and metallic mercury, 

 for the purpose of removing the hydrochloric acid contained in it. After 

 standing some time and being frequently agitated the liquid was filtered, 

 and sulphuretted hydrogen was passed through it in order to precipitate 

 the mercury in solution, and after being again filtered it was evaporated. 

 The residue left on evaporation was dissolved in a little water, and the solu- 

 tion was mixed with alcohol as long as any precipitate was produced ; the 

 precipitate collected at the bottom of the vessel forming a brown glutinous 



* Eead June 21, 1866: see Abstract, vol. xv. p. 1. 



