508 



Mr. Gr. S. Johnson. 



and found that, notwithstanding the preliminary precipitation of the 

 concentrated nrine with lead acetate, a tarry mass is obtained after 

 the H 2 S treatment of the mercury precipitate, which stands much in 

 need of the re-crystallisation from alcohol recommended by Maly, 

 before it will yield distinct crystals. If, however, the precipitate first 

 formed by mercuric chloride in Maly's process be separated by imme- 

 diate filtration, and only the precipitate produced in the filtrate on 

 standing be decomposed by H 2 S, all goes smoothly and well. The 

 preliminary precipitation by lead acetate and the artificial concentra- 

 tion of the urine are quite useless. 



The crystals of the hydrochloride of the reducing base of urine, 

 obtained as above, are quite permanent in the air, and their weight is 

 unaltered by exposure to a temperature of 100° C. 



O3708 gram of the crystals (not re-crystallised) gave 0*3512 gram 

 of silver chloride, equivalent to 0*086881 gram of chlorine, or 

 23*43 per cent. 01. 



The formula C 4 H 7 N 3 OHCl requires 23*74 per cent. CI. 



The crystals are excessively soluble in water, and also to a great 

 extent in alcohol. 



Mixed in aqueous solution with mercuric chloride, there is no pre- 

 cipitate, but on adding solution of sodium acetate, the spherical 

 mercury salt separates out. 



Mixed in aqueous solution with mercuric chloride and potassium 

 hydrate, there is first a whitish precipitate, which dissolves in excess 

 of the potassium hydrate, but the solution becomes turbid again after 

 a few seconds with formatiou of a yellowish precipitate, which imme- 

 diately afterwards becomes black by spontaneous reduction. 



Mixed in aqueous solution with Nessler reagent, a bright yellow 

 precipitate separates out, which rapidly becomes black by spontaneous 

 reduction, a compound ammonia being evolved at the same time. 



When an alcoholic solution of the hydrochloride of the reducing 

 base of urine is mixed with excess of an alcoholic solution of platinic 

 chloride, a yellow crystalline platinum salt is immediately precipitated. 

 These crystals appear dendritic under the microscope. They are 

 anhydrous, and permanent in the air. 



When dissolved in water, and spontaneously evaporated, a fine 

 orange- coloured prismatic platinum salt is formed, which loses water 

 at 100° C, becoming opaque and of a lemon-yellow tint. The same 

 orange-coloured prisms are obtained by spontaneous evaporation of a 

 mixture of the hydrochloride of the reducing base with platinic 

 chloride in aqueous solution. 



The determination of the water of crystallisation in these orange- 

 coloured prisms shows that they contain (on the average) 5*32 per 

 cent, of H 2 0. 



