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To protect one’s grain or other property against insect pests 
he must either build his granary or storerooms in such a way as 
to permit effective fumigation, or he must provide a properly built 
room to be used especially for fumigation of infested materials. 
This room may, of course, be of any convenient shape, but it should 
not have more windows or doors than necessary, and it should 
not contain more than fifteen thousand cubic feet of space. The 
walls, ceiling, and floor should be similarly constructed—built, that 
is, of two layers of seasoned, grooved flooring of good quality, the 
outer layer running at right angles to the inner, and with glazed 
building paper between the two. Care must be taken with this 
layer of paper, as it is an important part of the structure. Wherever 
the edges are joined they should be broadly overlapped and secured 
by gluing. The door should be similarly constructed. The in¬ 
terior of the building should have all cracks, crevices, and holes 
closed by putty, after which it should receive a heavy coat of paint 
and should then be lined thruout with linen cloth stretched tight, 
lapped at the edges, and held in place by lathing. This cloth should 
be so placed that the laps do not come at the corners of the room, 
and it should be finally coated with moderately thick carpenters' 
glue, which substance has the great advantage that it is insoluble 
in carbon bisulfid. It must, however, be renewed if it cracks and 
scales off, as is sometimes the case, especially when the lumber is 
not well seasoned. The door should be treated like the walls. It 
should fit as tightly as possible, and clamps similar to those on 
refrigerator doors should be used to batten it. 
THE USE OF COLD AND HEAT 
It is a well-known fact that insects are peculiarly sensitive to 
sudden and extreme changes in temperature, and under storage 
conditions this susceptibility can often be made use of to excellent 
advantage. A zero temperature following upon one of 50 0 or 
60 0 F., and quickly followed again by a temperature of ioo° or 
more, will commonly kill every insect in an infested mill or storage 
room. Where steam heat can be applied, especially in northern 
Illinois, granary pests can thus be readily exterminated. Indeed, 
a temperature of 125 0 to 130° F. maintained for several hours 
by artificial means will itself destroy most insects; but for this 
it is necessary to provide steam radiators near the floor, to use 
direct steam under pressure, and to close down the mill or other 
building for about twenty-four hours. 
Contact Insecticides 
In cleaning up infested places, cracks in the floor, walls, and 
ceiling must often he treated in a way to destroy the insects con- 
