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paranitrophenal had been added as a mould inhibitor were left down 4-7 days before clearance
and 38"takes" (2 complete, 7x¾, 19x½ and 10x¼) were recorded, 10 bodies being recovered.
A heavy rainstorm occurred mid-day on the first day of examination after the baits had been
down 4 days.
The comparable poison control of the second series produced 91 "takes" (14 complete, 17 x
¾, 26x½ and 34x¼), 28 bodies being found. The similar control of the first series was 87
"takes" (8 complete, 7x¾, 39x½ and 33x¼) and 52 bodies were recovered.
The build-up in the interim period prior to this series was 52% less than in the comparable
period between the first and second series and the decrease in poison acceptance and the
number of bodies found followed a similar pattern.
The result of the second control was 25 "takes" (2 complete, 4x¾, 17x½ and 2x¼) of
411 manholes baited and 5 bodies were found. The weather was ideal and the baits were in
good condition when examined.
The comparable result of the similar control of the 2nd series was 45 "takes" (25 complete,
8x¾, 11x½ and 1x¾) and that of the first series 60 "takes" (11 complete, 7x¾, 18x
½ and 24x¼) and 14 and 34 bodies respectively were found.
For the third control 402 entrances were baited, the recorded result being 11 "takes"
(8x½ and 3x¼) and 3 bodies were found. The weather, with the exception of a few dry periods ,
was very wet, and 49 baits were recorded as washed away. The comparable results in the
previous series was 31 "takes" (7 complete, 5x¾, 3x½ and 16x¼) and 18 "takes" (4 complete,
4x¾, 8x½ and 2x¼).
The final control of the third series was applied in March, 1960, when 402 entrances were
baited and the recorded result was 43 "takes" (1 complete, 23x½ and 19x¼ or less) and 5
bodies were found. The result of the comparable treatment of the second series was 29 "takes"
(8 complete, 3x¾, 9x½ and 9 x ¼ or less) and that of the first series, 17 "takes" (4 x \
and 13x½).
The annual overall test baiting was applied 21 days after the completion of the series and
the baits comprising soaked wheat were left down four days. On examination 41 "takes"
(38 complete and 3x¾) were recorded and 410 sewer entrances were baited. There was, during
three nights, prolonged rain and although only four baits were recorded as washed away there is
a possibility that others were similarly affected.
The comparable test result on completion of the first series was 27 "takes" (15 complete,
9x¾, 1x½ and 2x¼) and that of the second series 21 complete "takes".
A total of 25 dead rats were found during this' series as against 52 for the second and 110
for the first series making a total of 187 for the series comprising 12 treatments with Fluoracetamide.
During the former series which comprised 17 "direct" poison treatments with Sodium
Fluoroacetate 319 bodies were found, and when combined with those found as the result of the
Zinc Phosphide "direct" controls, and the pre-bait treatments prior to the institution of the
"direct" method the sum is 1,092. It is emphasized that this figure refers only to those found
by the Rodent Operators near the baiting sites at the base of the entrance shafts or nearby in
the flows, when examining the baits, and does not include any subsequently found by the
sewermen during their routine work.
Assessing the relative values of Mono Sodium Fluoroacetate ("1080") and Fluoracetamide
("1081") in light of the detailed information collated, close observation of the treatments carried
out in the varying seasons, and making due allowance for the vagaries of the weather,
during each treatment, it does appear that the results achieved with the former can in similar
conditions be obtained with Fluoracetamide, thus providing an alternating control as at present
carried out in the City.
These conclusions, reached as the result of this work under practical conditions, are
confirmed by the Scientific Officers, Infestation Control Division, as a consequence of controlled
laboratory and field trials. This information is contained in the Ministry circular P.D.P./196Q/3
approving the use of Fluoracetamide and recommending the procedure of application similar to
that applied in the City since 1951.
MASS RADIOGRAPHY
The Mass Radiography Unit of the North East Metropolitan Regional Hospital Board continued
to operate at the Corporation's premises at 20 Golden Lane, London, E.C.I, where 41,853
persons (24,836 men and 17,017 women) were X-rayed during the year. In addition 22,503 employees
of business organisations in the City (13,112 men and 9,391 women) were screened when
the Unit was "mobile", i.e. when operating at the premises of large firms where employees are
X-rayed at their place of work.
Although the Unit is also available to the Boroughs of Finsbury and Shoreditch, the majority
of examinees are employed in the City.
The following is an Extract from a Report received from the Medical Director of the Unit,
Dr. W.D.R. Thompson.
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