PROC. ENT. SOC. WASH., VOL. 21, NO. I, JAN., 1919 19 



25 minutes 29 .5-32 C. ca. 130 5-7 days 64 49 .2% 



30 minutes 29. 5-32 C. ca. 200 5-7 days 2.5% 



Gasoline insecticidal soap 



emulsion, then rinsed in 



water for 2 minutes: 



5 minutes 31 C. 126 4-6 days 81 64 .2% 



10 minutes 31 C. ca. 240 4-6 days 181 75 .4% 



20 minutes 31 C. ca. 185 4-6 days 165 89 .2% 



30 minutes 31 C. ca. 225 4-6 days 91 40 .4 ' , 



Insecticidal soap alone 



followed by rinse in 



water : 



5 minutes 23. 5 C. 90 .5-7 days 42 46.0', 



10 minutes 23 .5 C. 82 5-7 days 47 57.3% 



20 minutes 23. 5 C. ca. 180 5-7 days 150 83.3', 



30 minutes 23 .5 C. ca. 210 5-7 days 201 95.7% 



The results indicate that the gasoline-soap emulsion has little 

 or no effect in destroying eggs of body lice. 



Conclusions. 



1. The open rotary washer system of dry cleaning, when done 

 according to the specifications quoted, is entirely effective in 

 destroying both the active stages and the eggs of body lice and has 

 additional advantages in the cleansing of the garments and absence 

 of shrinkage. 



2. The high temperature required in the drying tumbler was 

 found to be essential for the destruction of the eggs. 



3. The wash and rinse in gasoline are effective in destroying 

 active stages but a large percentage of the eggs will survive this 

 part of the process. 



4. Gasoline itself is of no value as an ovicide, 18.7% of the 

 eggs in one test hatched after 54 hours' immersion in gasoline. 



5. An attempt to find a washing formula which of itself would 

 be effective without depending on the high temperature of the 

 drying tumbler was not successful, although results of one experi- 

 ment with benzol, 30.5 Baume, indicated that the oil could be 

 used for this purpose, if infested garments were soaked 2 to 4 

 hours before washing. 



6. A preliminary soaking in kerosene or in a 52 Baume kero- 

 sene-gasoline mixture followed by washing in gasoline was found 

 in laboratory tests to be ineffective. 



7. Laboratory tests with a series of oils showed that benzol 

 (30.5 Baume) killed after 2-4 hours' immersion; kerosene 

 (44 Be.) killed within 10 minutes; gasoline-kerosene mixtures 



