1867.] 



Extractive Matters of Urine. — Part I. 



Ill 



after tlie liquid had been poured off, was dissolved in water, and the solu- 

 tio mixed with acetate of lead and alcohol. The dirty- white precipitate 

 thereby produced was filtered off, washed, dried, and analyzed. 



IV. 0-,5750 grm. gave 0-5355 grm. carbonic acid and 0*2010 grm. water. 



0-7260 grm. gave 0-2595 grm. chloride of platinum and ammonium. 



0-3585 grm. gave 0-1930 grm. sulphate of lead. 



In 100 parts it contained therefore 



C 25-39 



H 3-88 



N 2-24 



28-91 



PbO 39-58 



100-00 



The substance combined with oxide of lead contained, in 100 parts, 



C 42-02 



H 6-42 



N 3-70 



47-86 



100-00 



The results obtained in this analysis approximate to those yielded by 

 Analysis II., Series D. 



The mixture of chloride of lead and extractive matter («) which was ob- 

 tained in this series of experiments was also examined, and a lead compound 

 was prepared from it which was submitted to analysis. The results, how- 

 ever, do not possess sufficient interest to make them worthy of communica- 

 tion. They served to show that the organic portion of the mixture did 

 not differ in composition very widely from the extractive matters, the com- 

 pounds of which had been previously analyzed. 



It was about this time that I made a discovery of some interest connected 

 with the chemistry of urine. I was occupied with the examination of the 

 lead precipitate produced by ammonia in the liquid filtered from the pre- 

 cipitate with basic acetate of lead, and having treated it in the manner 

 above described for the purpose of separating the extractive matters con- 

 tained in it, I obtained an alcoholic solution of the latter, to which I added^ 

 as usual, a quantity of ether, and I observed after some time, mingled with 

 the glutinous deposit produced by the ether, a quantity of crystalline 

 matter. On pouring off the liquid and adding a little cold water to the 

 deposit, the crystalline portion was left undissolved, and after filtration and 

 washing had the appearance of a silky mass of a brownish hue. By dis- 

 solving it in boiling water and adding animal charcoal, the colour was re- 

 moved ; and on evaporating the filtered liquid I obtained a substance, crys- 

 tallizing in white silky needles, which had the properties of tyrosine. It 

 was very little soluble in cold water, and crystallized from the solution in 



