made. The chemical work of these Investigators and their 

 conclusions are given here in some detail for the sake of 

 completeness. 



Khittel's Investigation. 



The first attempt to find the poisonous constituent 

 was made by Khittel in 1857, His work was published in 

 Wittstein's Vierteljahrresschrift for praktische Pharmaoie , 

 VII. 348-359 , Khittel obtained 37-l/E oz. of fresh leaves 

 of poison ivy from the botanical garden in Munich, dried 

 them, and got a residue of 9-1/2 oz. which he analyzed, 

 lot detecting anything to which the poisonous qualities of 

 the plant could be attributed, he made another series of 

 experiments which^as he thought, showed that a volatile 

 alkaloid is the poisonous constituent. It was obtained 

 by the following process: "3 oz, of the powdered leaves were 

 Infused with hot distilled water, after three days strained, 

 expressed, the liquid evaporated to 3 oz. , and with the ad» 

 dition of potassa^ carefully distilled to one-half. The 

 clear, colorless distillate had an alkaline reaction, and an 

 odor resembling henbane or hemlock. It was saturated with 

 sulphuric acid, evaporated and treated with a mixture of 

 equal quantities of alcohol and ether which left sulphate 

 of ammonia behind, the solution was evaporated spontaneous- 



1. A free translation of thi^; paper ij given in Amer, 

 Jour. Phanri. for 1558, p. 542, 



