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authority, and this has now been overcome in Tottenham by arrangements
having been made for the County Council to delegate their
powers under this Act to the local authority.
The following is a report made by the Chief Sanitary Inspector
to the Public Health Committee, regarding the first stages of rodent
control in relation to sewers.
INTRODUCTION.
The rat population in sewers, drains and the adjacent
ground is admitted to be the cause of a high proportion of the
many infestations above ground in heavily built up areas.
The type of rat which so infests these places is the Brown rat,
or common rat, often called a sewer rat. Movement to and
from the sewers is probably made through defects in the sewers
themselves or, perhaps, more frequently through fractures in
the drains. This movement can occur in two directions; along
the sewers and drains themselves, where there is normally a
large amount of foodstuffs available, or up into the surrounding
buildings, which may or may not contain food. When the
rats which gain access to the surface find a source of food supply,
more and more are drawn up, and thus infestation of the
premises takes place.
OBJECT AND PLANNING OF THE TREATMENT.
The object of the treatment is obviously then, destruction
or extermination of the greatest number of the rat population
which exists in and/or can be attracted to the sewers, over as
large an area as possible in the minimum of time. This object
has been achieved by placing at given points in the sewers,
foodstuffs which will provide food for those rats which might
normally feed there, and to keep in the sewers those rats which
may normally come up to the surface. This is termed baiting.
This baiting can only be carried out at the manholes, and
therefore the number of baiting points cannot be increased or
decreased according to the degree of infestation, even if this
were known.
The scheme provides for baiting with unpoisoned food to
be carried out for four days, known as the pre-baiting period.
Some criticism may be made that four days is too long, and