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pre-bait of sausage rusk with poisoned sausage rusk at a
concentration of 0.025% and build each point up to 100 grams
of the dry mixture.
The thirteen stations comprised 24 of such points, with
one or more points at each station according to demand. The
cardboard bait trays were secured to the wood floor by press
pins. The stations were visited each succeeding day save
holidays, the consumption of bait recorded and each point
restored to 100 grams.
It was on the fifth day that the first dead or moribund
rats were found on open spaces. Thereafter more were found on
various floors and on the roof. The size and sex of those
recovered was recorded and after 11 days the poisoned baits
were lifted.
It is noteworthy that of the rats recovered from this
operation, ninety per cent were females and ten per cent of
these were not more than two months old.
After three days a tracking dust was laid,and this indicated
that a substantial residue of the rat colony still remained.
What of this residue? This operation had taken two -weeks
and resulted in the recovery of thirty seven rats, although it
is probable that many may have died in obscure harbourages or
among the stored cargo. To avoid any more damage to cargo it
was decided to try extermination of the remaining rats with "1080"
"1080" As a check on the value of "Compound 42", under the
stances in this warehouse, twenty points, each of one fluid ouna
of poisoned water at a concentration of 0.25% were distributed
over the top floor only and left for five days without being
replenished, although some containers were dry on the third day.
Each day the dead rats lying on open spaces were collected and
checked.
On the fifth day, the entire warehouse of four floors was
treated with liquid "1080". One hundred and fifty points were
laid and left for five days. Ihen the one-ounce containers
were collected, they were dry, the poisoned water having been
consumed by the rats, only a small amount having been lost by
evaporation. Tracking dust was again laid on the top floor for
two days and only one rat run was found.
Summary "Sorexa" at 0.025% laid for 11 days at 24 stations on top floor
Rats recovered from various floors 33 Females)
4 Males )
"1080" poisoned -water 20 points of 1 oz. laid on top floor
Rats recovered in 5 days:- 51 Males )
25 Females )
"1080" Poisoned Water150 Points laid through to clear.
Rats recovered in 5 days 41 and 24 Mice
" " " 8 " 70 " 24 "
Total rats "SOREXA":- 37
" " 1080" 146 and 24 Mice
(16)