View report page

72
I am indebted to Messrs. Walton & Sons, professional rat-catchers, for the information
that, during the year, they caught 26,713 rats in the City. It is, of course, impossible to
estimate the number of rats destroyed in the City area during the year ; the impracticability
of giving even an approximate estimate was pointed out in a special report I presented to
the Sanitary Committee on the 26th September, 1922.
Rat-catchers and poisoners are engaged on contract in many of the multiple tea-shops,
restaurants, hotels, and business premises; several vacant building sites in the City were
dealt with under the supervision of the Department, and all necessary information was
given to representatives who called for advice.
The attached Table shows that of the 1,044 buildings visited during the year, 412 were
found to be rat-infested, and in these rat-proofing work was carried out at 341. This work
chiefly consisted of wiring area gratings, ventilators, roof openings, and the stopping of rat
holes in walls and floors. Other necessary work, such as the removal of wooden floors from
basements and substituting concrete, the stripping of internal walls of the woodwork, such
as matchboarding, wainscoting and panelling—behind which rats nest and breed—the
cementing of walls and the removal of ceilings in certain cases could only be done to a very
limited extent, because it would not be considered a reasonable request to ask an occupier
to carry out this expensive work in a building which he does not own.
Rat Week.—No special efforts were put forward during Rat Week. Rat repression
work in the City being continuous, it is difficult to see what advantage can be gained by
distributing circulars to firms who are doing their utmost (in their own interests) to deal
adequately with the rat nuisance. Moreover, in previous years some of those firms have
expressed their irritation on receipt of those circulars.
Virus.—There has again been some little controversy as to the use of Bacterial preparations
in the City. It has been the practice of this Department not to encourage the use of
these preparations in City premises, the reasons for which I have set forth in detail in my
previous reports.
Varnish Traps.—Varnish traps continue to be used throughout the City with very
great success. It has been found by experiment that the most effective bait for these traps
is wholemeal bread.
There are very few firms now that are not acquainted with the use of these traps, and
many users prefer this method of destroying vermin.
Break-back Traps.—Break-back traps also are in general use, and bread again is found
to be the most satisfactory bait. A good method of using this trap is to fix a small screw
ring in the end of it furthest from the bait, and to suspend it on a nail driven into the skirting,
with the bait an inch or so from the floor. Rats at night frequently run round the skirtings
of a room, and are not accustomed to find a trap in this position ; frequently the trap is
found snapped off and the rat lying dead a little distance away.
Poison.—The poison chiefly recommended is Red Squill Extract. Pieces of bread
about 1 inch cube are soaked in this and placed about in rat runs. Some authorities have
estimated the number of rats killed by the number of baits taken, e.g., if 1,000 baits have
been taken, it has been presumed that at least 300 rats have been killed. Many instances
in the City have frequently shown the fallacy of this method of calculation. Baits have
been laid and counted, and the following morning most of the baits, or perhaps all, of them
have disappeared. A few days later the majority of the baits have been discovered behind
packages or stores in the building, moved there by the rats. One rat will frequently remove
numbers of baits. Piles of poison bait are often found under floors. A liquid bait is therefore
preferable to a solid or semi-solid one, which can be carried away.
I think it can be safely said that the number of rats in the City is being kept down, but
the species R. Rattus, or the Old English black rat, appears to outnumber R. Norvegicus,
the so-called sewer rat, by at least 3 to 1.
Old City men have said that thirty or forty years ago they were unable to enter their
office in the morning until the rats had been cleared out. We hear of nothing so alarming
nowadays. These rats were probably of the brown variety, for in those days very few
black rats escaped from their attack. They were practically exterminated. Now that the
sewers and drains of the City have had so much attention, the brown rats have been greatly
reduced in numbers in them, and they have been poisoned and trapped unceasingly. This
and overhead travelling facilities, electric cables, etc., have given the black rat his chance,
and being a wonderful climber, no place is secure from his invasion. Newly-constructed
buildings which are of solid construction offer no difficulty of access to these black rats,