toxicodendrin, 



OZIDATIOl OF THE PURIFIED TAR 7/ITH HITRIC ACID. 



When the purified poisonous material (p. ^ 



extracted with 5O70 alcohol, only a small quantity was dis- 

 solved as was stated above. The insoluble residue was 

 treated with fuming nitric acid. Violent reaction took place 

 at once v/ith copious evolution of red fumes and heat. ^en 

 the reaction was over, a sticky red gummy mass was left 

 which was slightly soluble in warm alcohol. The ?/ater ex- 

 tract was yellow, and the alcoholic solution was red. That 

 the water extract contained picric acid was shown by the 

 following experiments: 



(1) A portion was gently v/armed with a few drops of a 



strong solution of potassium cyanide and two drops 

 of sodium hydroxide. The red color of potassium 

 isopurpurate was formed. 



(2) A portion of the water solution v/as heated v;ith 



glucose and a few drops of sodium hydroxide. 

 The deep red color of picramiinic acid was pro- 

 duced. 



(3) A few drops of an aramoniacal solution of copper 



sulphate was added to the water extract. A 

 yellow-green precipitate was formed. 



(4) The water extract dyed silk, but did not dye 



cotton cloth. 



-51- 



