The simultaneous use of a DDT solution or suspension in all 
parts of en infested house or outbuilding and the dusting of all 
animals with a DDT powder should relieve a heavy infestation with 
one treatment • Although fleas may be noticed for several days after 
the treatment g the DDT eventually kills them* 
Types of DDT Insecticides 
DDT must be prepared is & suitable formulation before it can be 
wsvd as tn effective insecticide* Several types of DDT formulations 
ara now on the acarket. These include aerosols, dusts or powders, 
solutions, emulsions, and water-die per s it le powders. The quantity 
of DDT in various commercial preparations especially emulsions and 
water-dispersible powders varies widely, therefore for satisfactory 
results, the directions given on the container should be olosely 
followed. 
DDT is a slow-killing insecticide requiring in some instances 
several days to markedly r-aducs an infestation, furthermore, DDT 
powders, «hen applied to a dog for example 9 will greatly stimulate 
activity of the fleas. Since all the fleas may not leave the animal 
immediately, for several hours it is very likely to show signs of 
greater discomfort than before the powder was applied. 
Cautions 
DDT should always be used with reasonable caution, beoause it 
is a poison * On the basis of the toxicity data presently available, 
however / "i? is believed that no appreciable risk is involved in the 
household use of preparations containing the amounts of DDT recom- 
mended in this circular, provided the users carefully observe the 
caution statements recommended by the Insecticide Division of the 
Production and Marketing Administration, which are as follows t 
1, For straight DDT Technical .—DDT is toxic and when in solu- 
tion can be absorbed through the skin. Avoid inhaling 
dusts and mist fr ear spray* Avoid contamination of food- 
2, For petroleum oil solutions containing not more than 25 
percent DDT Technical. —This solution if brought into re- 
peated or prolonged contact with skin can cause toxic 
symptoms. Avoid excessive inhalation and skin contact* In 
case of spillage on the skin wash with soap and water. 
Avoid contamination of foodstuffs. Do not use on household 
pets or humans, 
3, For combustible mixtures .-"Same as Ho. 2 above. Do not 
spray near fire. Do not smoke while spraying. 
