-9- 
temperatures as low as -20°F. The War Departments specifications for 
DDT spray have been revised to require the inclusion of this substance. 
—Anon* ( 35 ) • 
The solubilities of pure DDT, m.p. 107-108*^ in nine organic sol- 
vents (acetone, benzene, carbon tetrachloride, chloroform, dioxane, 
ether, ethanol (95%), petroleum ether (30-60°), and pyridine) at 0°, 7,2°, 
24 , 45 , and 48°C. were determined. At all temperatures except 0°C. 
the solubility is greatest in pyridine, and at that temperature it is 
greatest in acetone. Benzene is the most efficient stripping solvent for 
pure DDT at room temperature.— Gu nth er ( 193) . 
Methylene ohloride is an excellent solvent for DDT and can be used 
as an auxiliary solvent to make it more soluble in Freon-12 (dichlorodi- 
f lu or om ethane) • Dimethyl ether and methyl chloride are good solvents 
for DDT .—Goodhue et al. (181 ). 
The following solvents for DDT were used in tests upon houseflies 
and cockroaches: Deobase, acetone-Deobase, toluene, Deobase^mineral oil, 
and cyclohexanone.— Goddin and Swingle (179 ) . 
At room temperature the solubility of DDT in some of the common 
solvents is as follows: 
Solvent Grams per 100 ml . Solvent Grams per 100 ml . 
Cyclohexanone ••••• 100 to 120 Kerosene, crude .. 5 to 8 
Xylene •••• 56 Kerosene, purified 2 to 4 
Ether 29 Ethyl alcohol.... 1.5 
Diesel oil No. 2... 10 
Calif. Agr. Expt. Sta. (101 ). 
EFFECT OF SOLVENTS FOR DDT ON ITS TOXICITY TO INSECTS 
Laboratory tests conducted at Beltsville during the winter of 1944- 
1945 indicate that the nature of the solvents used with TOT has an impor- 
tant bearing on its toxicity. Some solvents, such as kerosene, evaporate 
quickly (a matter of minutes), leaving needlelike crystals that are very 
durable, the toxic effects lasting from 3 to 6 months under outdoor 
weathering. These tiny crystals may penetrate the footpads of "the insects 
and possibly enter the pores in the 6clerites of the body. Velsicol AR-50 
(a mixture of mono- and di-methylnaphthalene) produces similar crystals, 
but these require a day or more to form. Heavy solvents, such as Diesel 
oil, remain tacky for days and leave a deposit that is not so persistent 
as that resulting from kerosene. On the other hand, these tacky or 
viscous films kill several times as quickly.— Craighead and Brown (125) • 
