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out with a mixture of othodichlorbenzine and carbon tetrachloride, with results
which appeared to be highly satisfactory.
Any gasesous disinfectant is unlikely to be satisfactory for use in the
disinfestation of a timber framed hut, when the timbers are warped and the
inside lining is broken, and it was for that reason that this mixture was used,
carbon tetrachloride being extremely toxic to the bed-bug. The number of
huts so treated was 7.
(II) Procedure in Routine Disinfestations—
(a) Sulphur Dioxide.—More use has been made of this chemical than any
other, and the methods used, which briefly can be described as gaseous disinfection
plus cleansing, have been successful with one treatment only in 84 per
cent. of all cases.
(b) Orthodichlorbenzine.—In the report for 1933 I referred to experimental
work carried out with this chemical which promised well. Briefly its fumes are
so irritating to the bed-bug that it leaves its resting places much in the same
way as rabbits are bolted by ferrets. Further experience has shown that
ODCB is a valuable adjunct to our armamentarium against the bed-bug. Our
knowledge of its efficiency justifies a more detailed scientific investigation of
its action as it has been used only in an empirical manner up to now. So far
we have only used it in empty houses but it has been used in other areas in
occupied rooms as well. The method we have followed is as under :—
(1) Space between floor and skirting, and wall and skirting, are cleared
of dust and dirt by putty knife or similar tool;
(2) Visible openings at architraves and mouldings are enlarged with same
knife;
(3) Built in cupboards especially those next to fireplaces, are carefully
inspected and a similar procedure is carried out where this is possible.
(4) Openings are made into any obvious cavities such as window frame
pulley boxes, and other cavities such as are sometimes found around chimney
breasts between the latter and the trimming and trimmer joists.
(5) The room is now ready for spraying. In doing so the general idea is
to endeavour to dislodge the bed-bug from his hiding places by means of the
fumes and then to drive him on to an open surface, where he is accessible to
orthodichlorbenzine concentration. Following out this idea, the cupboards,
the obvious and other cavities, the edges of the architraves and all mouldings,
and the floor next the skirtings are sprayed with orthodichlorbenzine. When