19 



acid. The black precipitate which separated from the watery solu- 

 tion on evaporation was washed, and upon adding hydrochloric 

 acid, changed to a red color, but remained insoluble in all ordinary 

 solvents. There was not a sufficient quantity for analysis, but 

 doubtless was the same substance which is formed as often as 

 the lac is oxidized and henceforth will be designated as oxyurush- 

 in. Its presence in the water solution was due to the acetic acid, 

 which is an excellent solvent for the unoxidized lac. 



One hundred grammes of the lac was placed in a flask and 

 steam passed through the lac for several hours. The distillate 

 was covered with a thin oily film, which was removed by shak- 

 ing out with ether and evaporating. The residue was not volatile 

 or poisonous. Besides this the distillate contained acetic acid. 



A portion of the alcoholic residue was dissolved in ether 

 and repeatedly shaken out with one per cent solution of sodium 

 carbonate. The carbonate solution was at first green, 

 then brown. This was heated on a steam bath to remove the dis- 

 solved ether, and acidulated with hydrochloric acid, when a small 

 quantity of reddish brown precipitate appeared. This was wash- 

 ed and dried. Only a small part of it was soluble in ether, the 

 remainder being insoluble in any of the ordinary solvents, and is 

 evidently oxyurushin. ,. .,.,. 



The ether solution which was separated from the carbonate 

 solution was next shaken out with one per cent potassium hy- 

 droxide solution. The resulting solution was very dark green, 

 changing later to brown. It was treated exactly as in the case 

 of the carbonate solution and with the same result, i. e. a sepa- 

 ration of the same insoluble oxyurushin. 



The ether solution then received attention. It was shaken 

 out with 5% potassium hydroxide, producing a black precipitate 

 which floated in the ether solution. The alkaline solution was 

 again of the same dark green color changing to brown, and 

 when acidulated produced the same insoluble oxyurushin. The 

 black precipitate was removed from the ether by filtration and 

 the ether shaken with more alkali with the same result. By re- 

 peating the operation a sufficient number of times, the entire 

 substance could be removed from the ether. The black precipi- 

 tate formed by potassium hydroxide was washed free from alkali 

 and heated with dilute hydrochloric acid, washed, dried and pow- 

 dered ; a very small part of it was soluble in ether but this became 

 insoluble on evaporation. The powder was reddish brown and 



