lo Fractionation of Phosphotungstic Acid Precipitate 



a little alcohol was added to make the lead sulfate more insoluble, 

 the precipitate was filtered off, and the filtrate freed from excess of 

 lead with hydrogen sulfid. This filtrate was evaporated in vaciio 

 at 25 °C., but the residue did not crystallize, The results of the 

 animal experiments are indicated on page 7. 



Precipitation tests were applied to the Solution with the results 

 indicated below : 



Picrolonic acid, -\- 



Picric acid, — 



Gold Chlorid in water, + ; in alcohol, — 



Platinic chlorid in water, — ; in alcohol, -\- 



Mercuric chlorid in water, + ; ii^ alcohol, + 



To the residue alcohol w^as added, and then an alcoholic sol. of 

 mercuric chlorid, tili complete precipitation occurred. The precipi- 

 tate, separated by filtration and washed with alcohol, weighed 3.5 

 gm. 



Mercuric chlorid precipitate. The mercuric chlorid precipitate 

 was decomposed with hydrogen sulfid. After evaporation the fil- 

 trate did not crystallize. The residue was dissolved in alcohol and, 

 after precipitation with alc. platinic chlorid sol., yielded 0.68 gm. 

 of platinum Compound. The filtrate, freed from platinum with 

 hydrogen sulfid and precipitated with picrolonic acid, yielded 1.25 

 gm. of picrolonate. The filtrate was freed from picrolonic acid by 

 extraction with ether. The Solution still contained 0.0317 gm. of 

 nitrogen, estimated by the Kjeldahl method, but did not crystallize. 

 An alcoholic sol. gave, with an excess of mercuric chlorid, a small 

 quäntity of precipitate, but not enough for chemical study. 



Mercuric chlorid filtrate. The liquid was freed from mercury 

 with hydrogen sulfid, filtered and the filtrate evaporated in vacuo. 

 The residue, which did not crystallize, was dissolved in alcohol and, 

 precipitated with platinic chlorid, yielded 1.48 gm. of platinic Com- 

 pound. The filtrate was freed from platinum with hydrogen sulfid 

 and precipitated with picrolonic acid. The resultant picrolonate was 

 more soluble than the product with mercuric chlorid, and weighed 

 0.9 gm. The filtrate from the picrolonate, freed from picrolonic 

 acid with ether, contained 0.0522 gm. of nitrogen (Kjeldahl 

 method). 



