1867.] 



Extractive Matters of Urine. — Part I. 



115 



III. 0-5855 grm. gave 0-4100 grra. carbonic acid and 0-1230 grm. water. 

 0*7835 grm. gave 0-1625 grm. cliloride of platinum and ammonium. 

 0-4300 grm. gave 0-3265 grm. sulphate of lead. 



0-5085 grm. gave 0^0800 grm. chloride of silver, equivalent to 0'0777 

 grm. chloride of lead. 



These numbers lead to the following composition : — 



C 19-09 



H 2-33 



N 1-30 



O 18-39 



PbO 43-60 



PbCl 15-29 



100-00 



The composition of the extractive matter contained in this lead com- 

 pound corresponds with the formula Cg^ H^- NOo^, which requires 



Calculation. Experiment. 



C,, ........ 228 46-24 46-44 



H,, 27 5-47 5-66 



N" 14 2-83 3-16 



224 45-46 44-74 



493 100-00 100-00 



The substance {d) was treated with cold water, which dissolved the whole 

 of it, with the exception of some chloride of lead which was filtered off. 

 Sulphuretted hydrogen was passed through the liquid in order to precipi- 

 tate the lead in solution ; and having been again filtered, it was stirred in a 

 mortar with sulphate of silver, by which means the hydrochloric acid as 

 well as the excess of sulphuretted hydrogen contained in it were removed. 

 Through the filtered liquid sulphuretted hydrogen was passed in order to 

 precipitate the silver in solution. It was then filtered again, agitated with 

 carbonate of lead in order to remove the sulphuric acid, filtered, freed from 

 excess of lead by sulphuretted hydrogen, filtered again, and then evaporated 

 in the air-current to a syrup. This syrup having been dissolved in water, 

 acetate of lead was added to the solution, which after filtration was mixed 

 with a large quantity of alcohol. This produced a precipitate, which was 

 filtered off, washed with alcohol, suspended in water, and decomposed with 

 sulphuretted hydrogen. The filtered liquid was evaporated in the air-cur- 

 rent to a syrup, which was treated with cold alcohol until all the soluble 

 matter was removed. The portion insoluble in alcohol* was dissolved in 



* A part only of tliis v>-as employed in the preparation of the lead compound. Tlie 

 remainder was kept in a flask for a considerable time. It was then found to hare depo- 

 sited a quantity of crystalline matter, which remained undissolved on the addition of 

 cold water, but Aras soluble in boiling water. The boihng solution, after being decolo- 

 rized with animal charcoal and filtered, deposited, on cooling, a quantity of tyrosine in 

 white crystalliue needles. 



