stances associated with it in the plant were first identified; 

 the scope of the work was therefore extended to an investiga- 

 tion of the other conctituents of the plant, and it was hoped 

 that a knowledge of Ihe properties of these constituents 

 would suggest a more economical way of getting the poison 

 than the method of fractional precipitation. 



The crude material for thia work was prepared "by Messrs. 

 Parke, Davis and Co., of Detroit, Ilich. according to special 

 instructions submitted to them: 67~l/2 lbs. of fresh leaves 

 and flowers of poiaon ivy were collected near Detroit and 

 carefully inspected by a competent botanist. This material 

 was thoroughly macerated and put into ten-liter bottles with 

 ether. The mass was thoroughly shaken, water being added 

 to msike it more mobile. The ether was then separated off 

 and the extraction was repeated three times in the same way 

 to insure complete ranoval of the toxicodendrol. The ether 

 extracts were combined, thoroughly dried with anhydrous sodium 

 sulphate, and the ether was distilled off, the temperature 

 being kept below 40 C during the entire distillation. The 

 residue after the removal of the ether was a thick, blaok, 

 tar-like mass, weighing 3 lbs. 11 oz. In extracting the 

 plant, about twenty-four gallons of ether were used. It is a 



significant fact in regard to the volatility of the poison 

 that during the process of preparing this material none of 



the employees engaged in the work were in any way affected, 



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