Circulsr 21 - Insecticides and Subsid iary Materials 57 
slightly poisonous. It possesses a strong, 
nauseating odor resemblin<^ that of moth balls 
which may persist for several days after appli- 
cation. 
Caution : The odor might cause headache 
to one confined with it in an enclosed space 
for an hour or so. In treating infested wood 
overhead, care should be taken to keep the 
liquid from dripping on the body as it might 
burn the skin slightly and would be especially 
painful if it came in contact with the eyes. 
Goggles should be v/orn :md the hands and body 
protected by rubberized fabric or necprene- 
treated gloves and apron. .U.though orthodi- 
chlorobenzerie is pr.ictically noninflaixuable , 
as a matter of precaution it siiould not be 
ato-iized in the air by spraying near a furnace 
while the l;itter is in operation. It shoi'ld 
not be used in the ground near v.ells or springs 
which serve as a source of drinking water. It 
should be kept away iroii exposed food materials, 
Orthodichlorobenzene :;i:iy be obtained in 
tanks, 1000-pouna druius, and 50- and 100-pound 
tins at a price ranging from 53 to 10 cents 
per pound. 
For manufricturerti and distributors see 
numbers 20, 3o, 37, 55, 70, 76, and 104 of 
list at end of this circular. 
oRvus ;;. a. 
Orvus v;. A. is a wetting and spreading 
agent which is used as an emulsifier in place 
of soap to prepare insecticides, because it 
does not form a precipitate as soap does when 
hard v;ater must be used. Like otlier similar 
wetters and spreaders, Orvus ',7. A. is especi- 
ally useful v/hen under certain conditions a 
