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Corporation of London.
Public Health Department,
Guildhall, E.C. 2,
2Ath February, 1920.
The Worshipful the Chairman and Members of the Sanitary Committee.
RAT REPRESSION IN THE CITY.
Gentlemen,
I have the honour to report as follows on the subject of rat repression
in the City :—
(1) For the past eighteen months the rat problem has been the subject of special
investigation work in the City. This work has been in charge of Mr. Mayne, who
was appointed Temporary Inspector for this particular purpose. Your Worshipful
Committee have been provided with several pamphlets which have been published on
this subject, and the present Report, therefore, need not discuss, except in the briefest
possible manner, such points as natural history, the damage done by rats and the dangers
of rats to the community. In this latter connection I may recall the work of
Professor A. G. R. Foulerton on "The Protozoal Parasites of the Rat," which was
carried out on your behalf. The details of his research were printed and circulated
among interested persons and societies.
(2) NATURAL HISTORY AND HABITS OF RATS.—The two types of rats
found in the City are the black rat (rattus rattus), known also as the house rat or ship
rat ; and the brown rat (rattus vorveyicus). The City seems to house either rat
without special selection of district. Each type has been found in the Central area and
also in the districts nearer the docks. The two rats, however, differ considerably in
their mode of life and existence, and it is important to know the habits of the two
varieties in making inspections of the districts. The black rat is seldom found to enter
premises by drains or basements and does not as a rule burrow. It generally establishes
itself in walls, between floors and ceilings and in roofs. It is an expert climber and
not only gets to the roofs of houses and window ledges by means of stack pipes
attached to the walls, but travels long distances on overhead electric and telephone
wires. These rats may be seen on a bright night in the City crossing overhead from
street to street by these means. They enter premises by way of chimneys, windows,
roof ventilators and any other openings, and only a very thorough system of rat-proofing
will protect a building from their invasion.
The brown rat is always to be found in sewers and drains, and generally enters
a building through a defective drain or an unprotected area window. It is also a good
climber, but is not a "Blondin" like the black rat. It frequently burrows from a
defective sewer or sewer connection under the footpaths and works its way along until
it finds a weak spot in a basement wall or the brickwork of a coal-shoot where it gnaws
through and obtains entrance. It frequently breeds under the pavements, and many
nests of young rats have been found when flags have been lifted on the City side walks.
When recently examining a rat-infested house in Aldgate, it was found that
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brown rats had burrowed to such an extent in the basement that nearly half a cartload
of earth was heaped on the floor from their burrow.
These facts emphasise the necessity for keeping the sewers and connections in
sound conditions and the basement walls and floors thoroughly rat-proof.
At night, numbers of rats are always to be seen running about the streets. Some
of these gain entrance to buildings through unprotected area gratings, defective
basement lights and windows, and frequently through doors which have been left open.
In some cases where the entrance pavement has been laid with a slope in order to avoid
the necessity of a step, the doors, when closed, have a wide space underneath which
rats readily avail themselves of as an easy means of entrance into an otherwise fairly
rat-proof building.