PROC. ENT. SOC. WASH., VOL. 21, NO. I, JAN., 1919 17 



all ages and conditions after '2 hours' immersion it could be used 

 for a two-hour preliminary soaking of clothing followed by the 

 usual dry cleaning process. If this proves to be the case it will 

 provide what we sought, namely, a washing process which is 

 effective in itself without depending on high temperatures of the 

 tumbler. 1 



The method of soaking in kerosene and then washing in gasoline 

 as suggested by Mr. J. E. Fox was tested under varying labora- 

 tory conditions. Eggs were immersed for periods of from 2 to 5 

 minutes, then partially dried between blotters. Twenty-one 

 and one-half hours later they were immersed in gasoline for If) 

 minutes. They were also soaked in kerosene for 24 hours and 

 then immersed in gasoline for 2 hours. The following table 

 includes for comparison one record of immersion for 15 minutes 

 in kerosene followed at once by 15 minutes in gasoline: 



Kerosene Followed by Gasoline Rinse. 



Number of Age at Number Percentage 



Treatment. eggs. treatment. hatched. hatched. 



Immersion in kerosene 2 minutes 



and after 21 '/-> hours soaked 



in gasoline 15 minutes 300 5-7 days 150 50' , 



Kerosene 5 minutes then after 



121' '-, hours soaked in gasoline 



15 minutes .. 150 5-7 days 40 26. (!' ,' 



Kerosene 15 minutes then rinsed 



at once in gasoline 15 minutes. 460 5-7 days 215 46.7', 



Kerosene for 24 hours then rinsed 



at once in gasoline for 2 hours 5 Id 5-7 days 225 44 . 1 ' , 



In another series of experiments with the 52 Baume gasoline- 

 kerosene mixture, similar results were obtained; that is, the 52 

 oil alone was effective in 15 minutes, but when this 15 minutes' 

 immersion was followed by rinsing in gasoline, from .'}().(>% to 

 57.7% of the eggs hatched. It seemed to make no difference 

 whether the gasoline rinse followed at once or after an interval of 

 24 hours. On the strength of these laboratory tests, therefore, 

 we are of the opinion that a preliminary 24-hour soaking in either 

 52 Baume mixture or in kerosene will not render the washing 

 process entirely effective in destroying eggs. 



Gasoline-Soap Emulsion. 

 Grubbs' gasoline-soap emulsion, mentioned above, was de- 



1 Further experiments, completed since the above was written, show that 2 

 to 4 hours' immersion in benzol is entirely effective in destroying eggs, and 

 subsequent washing and rinsing in gasoline does not neutralize this effecl 



