Circular 21 - Insecticides and Subsidiary Materials 51 
Caution : When working with methyl 
bromide it is necessary to use a gas mask 
provided with a canister that will absorb 
this gas. The chemical is toxic and there- 
fore should not be allov/ed to come into 
contact with the skin. Containers of this 
gas should be stored in a cool, well-vonti- 
lated place outside of inhabited buildings. 
Methyl bromide is obtainable in small 
1-pound cans or in cylinders containing 10, 
50, or 150 pounds net. In 50-pound cylinders 
it sells for 70 cents per pound. 
For manufacturers and distributors 
see numbers 36, 37, and 67 of list at end of 
this circular. 
MrTSIL-\L OIL 
Sprays for the control of bedbugs 
generally consist very lar^:ely of a light 
mineral oil with small additions of pyrethrum 
extract. 
Mineral oil is derived from any oil of 
mineral origin, such as petroleum or shale 
oil, by refining. It is a mixture of liquid 
hydrocarbon which is colorless, oily, non- 
fluorescent, transparent, becoming thicker 
with cold. Mineral oil is used in medicine, 
insecticidal sprays, paints, varnishes, 
lacquers, and as a solvent. 
The containers in which mineral oil is 
shipped are various sized drums, ranging from 
34 to 75 cents per gallon depending on the 
viscosity. 
Available on contract: see Class 14, 
General Schedule of Supplies, Procureiaen^j^^l^Y 
Division, Treasury Department, ^^ AlSlT BOARl^ 
