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135 2. the distribution and penetration of the gas were not somewhat reduced. It was even to be accepted that gas losses through adsorption were especially elevated and that in cold rooms often a significantly greater decrease in humidity on the walls occurred than in warm rooms. In the laboratory on the other hand, the question to be answered was the extent to which the capacity for resistance of bed bugs in all forms of development to prussic acid is increased at low temperatures, and whether at low temperatures required higher grams per hour consumption could be detected through the desired prussic acid concentrations at practical fumigations. The experiments, carried out in both directions yielded the unequivocal corroboration of the opinion grounded in practical observation over many years, that the efficiency of prussic acid and the suitability of the Zyklon procedure encompasses a temperature range that with certainty reaches at least 10° below zero. Finally a question had been answered that first arose in 1925 after
the evacuation of a part of the Reich territory that had been occupied
by the Allies during an especially harsh winter. To be sure, at that
time they still did not have the insight into the dependency of the
poisoning efficacy of gases on temperature and contented themselves
with the statement that after fumigation, the obstacles could not be
overcome due to imperfect efficacy. However, in many cases, it
involved barracks that had been empty for weeks; the internal
temperature of the buildings at the time of the fumigation was
therefore generally not much higher than the external temperature,
which on many days reached -22°.
There was at that time not yet the necessity for and also no
possibility of a thorough examination because there seemed to be only
one special action involved whereas the normal fumigation activity had
its high point in summer and sank to a minimum in the cold times of the
year. Only with mill fumigation and combating other storeroom pests
was there already to be observed a significant difference in the number
of fumigations in warm and cold times of the year, because even some
customers chose the winter as the most favorable time of year for their
purposes. However, even in these cases, winter fumigation with zyklon
prussic acid had for years brought no disappointments. Examination of practical fumigation tasks. After numerous fumigation objects had already resulted in certainty from practical observation about the 100 percent mortification success even at room temperatures to -10°C, the above questions were thoroughly tested in specially designed barracks buildings. Some of the test results are summarized below: Speed of prussic acid from Zyklon. 1. Barracks building A, area 39,183 cubic
meters
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Last modified: October 10, 1998
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