1867.] 



Extractive Matters of Urine'. — Part I. 



105 



dissolved in acetic acid. The filtered solution was mixed with a large 

 quantity of alcohol, which produced a pale cream-coloured precipitate. 

 This was filtered olF and prepared for analysis in the usual manner. 



I. \'^7^D grm. of this compound gave 0*8 125 grm. carbonic acid and 

 0'2770 grm. water. 



2'0605 grms. gave 0'1175 grm. chloride of platinum and ammonium. 



0*6830 grm. gave 0*5 785 grm. sulphate of lead. 



These numbers lead to the following composition : — • 



C 16-11 



H 2'23 



N 0-35 



18-99 



PbO 62-32 



100-00 



The composition of the organic substance, combined with the oxide of 

 lead, may be expressed by the formula Cgg NO^g, which requires 



Calculation. Experiment. 



, > ^ 



C,, 516 42-68 42-75 



H,, 71 5-87 5-93 



N 14 1-15 0-95 



O,, ^ 50-30 50-37 



1209 100-00 100-00 



It will be seen that the Analyses VII. and IX. of Series A, which were 

 made with compounds prepared in the same manner as this, led to almost 

 the same composition. It must not be inferred from this that these were 

 all compounds of a pure substance with oxide of lead. It is more probable 

 that the oxide of mercury employed in their preparation had simply the 

 effect of removing certain substances from the solution with which it was 

 brought into contact, leaving a mixture of others, the quantities of which 

 stood in a certain unvarying ratio to one another. That the above formula 

 represents a mixture containing glucose is very probable, as I shall after- 

 wards show ; and, on the other hand, it is certain that a great part of the 

 extractive matters entered into combination with the oxide of mercurj^, as 

 the solutions, after being shaken up with the oxide, became several shades 

 lighter in colour. It is also not improbable that oxide of mercury causes 

 tlie extractive matters to undergo a certain degree of oxidation — a conclusion 

 to which the large percentage of oxygen yielded by the analysis just given, 

 as well as the two others, seems to point. In my subsequent experiments 

 I therefore ceased to employ oxide of mercury except as a means of puri- 

 fying the extractive matter insoluble in ether and alcohol. 



The mixture or compound of chloride of lead and extractive matter ob- 

 tained as usual in this experiment was employed for the preparation of a 

 compound containing less chloride of lead, the process being the same as 



VOL, XVI. I 



