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



vised for the purpose of treating the bodies of infested immigrants, 

 while their clothing and effects were fumigated. Gasoline rather 

 than kerosene was used in this emulsion on the strength of certain 

 published statements (probably Kinloch's) as to the effectiveness 

 of gasoline. Our results with gasoline led us to question the 

 value of the gasoline-soap emulsion. Laboratory tests were 

 therefore carried out with emulsions made according to Grubbs' 

 formula and used under conditions approximating the bathing 

 procedure described by him. The stock emulsion is made of 



Soap 1 part 



Water 4 parts 



Gasoline 4 parts 



The soap is dissolved in water by heating, then after removal 

 from the fire, the gasoline is stirred in until a good emulsion of 

 creamy consistency is formed. Before use this stock is diluted 

 in 5 to 10 parts water. 



We prepared two emulsions, one made with a cheap grade of 

 laundry soap and the other with a so-called insecticidal soap of 

 the formula 



Fuel oil 25.70', 



Paraffin oil 8.57', 



Oleic acid 42.16% 



NaOH solution, 32 Baume 23 . 57% 



In both cases the stock was diluted in five parts water before 

 the tests. The cloth with eggs attached was immersed in the 

 emulsion for periods of from 5 to 30 minutes, all of which are 

 longer periods of contact than would obtain in Grubbs' pro- 

 cedure in which a tank and shower bath followed immediately 

 after spraying the body. In our tests the eggs were rinsed 1 to 2 

 minutes in water after removal from the emulsion, dried between 

 blotters and returned to the incubator. A check was run with 

 insecticidal soap alone. Twenty-five grams of the soap were 

 dissolved in 200 cc. of water and this stock diluted in four parts 

 water. The results are given in the following table : 



Gasoline-Soap Emulsion. 



Temperature of Number of Age at Number Percentage 

 Treatment. emulsion. eggs, treatment, hatched, hatched. 



Gasoline-soap emulsion 



followed by 1 -minute 



rinse in water : 



5 minutes 29 .5-32 C. 122 5-7 days 50 41', 



10 minutes 29 .5-32 C. 02 5-7 days 14 22 .5% 



15 minutes 29 .5-32 C. 180 5-7 days 99 55% 



20 minutes 21) .5-32 C. ca. 220 5-7 days 132 tiO' , 



