View report page

33
(b) The Assistant Eat Officer's third duty is the examination of shore premises for
signs of rat infestation or rat Plague, paying particular attention to premises adjoining
the berths of vessels from Plague-infected ports. The whole of the Dock area is
systematically and regularly inspected, and specimens of the shore rat population in
all parts of the Port are regularly examined bacteriologically, so that, in the rare
event of Plague infection being communicated to the rats on shore, it should be
quickly detected and stamped out before it has spread extensively. Moreover, when
rat-infestation of premises is reported, the responsible persons are required to take
energetic measures of rat destruction, for rat Plague will spread rapidly in a rat-infested
area, whereas where rats are few it may never spread at all. It is of the greatest
importance, not only from the public health, but also from the commercial point of
view, that the Port of London should be kept free from rat Plague.
(2) Measures taken to prevent the passage of rats between ships and shore:—
The Port of London Authority have made Bye-laws requiring the Master of
every ship to cause all ropes and mooring tackle used for securing ships, either to
the shore or mooring buoys, to be fitted with guards, approved by the Authority, to
prevent rats passing from the ship to the shore, and to cause all empty cases, packages
and barrels to be examined before landing, to ensure that no rats are contained
therein. The removal of rats (alive or dead) from ships without previous consent in
v/riting of the Superintendent is prohibited. Bye-laws also prescribe that, when the
discharge or loading of cargo or the landing or embarking of passengers it not actually
proceeding, one gangway, whitened for a length of 10 feet at the end next the vessel,
may be used as a communication between the ship and the shore, and that the Master
shall not have or allow any other communication with the shore, unless the same be
fitted with guards, approved by the Authority, to prevent the passage of rats.
These Bye-laws are enforced by the officers of the Port of London Authority,
and the Sanitary Inspectors of the Port Sanitary Authority also call upon Masters
to put guards on their mooring ropes. But the well-known difficulties in regard to
the proper application and maintenance of position of rat-guards constantly occur,
and it cannot be said that the mooring ropes of the majority of ships in the Port of
London are at all times so guarded that a rat could not use them as a means of reaching
the shore. There is no doubt that rats very seldom voluntarily run along mooring
ropes, and the view is held that such rats as get ashore do so usually by some easier
means or accidentally in cargo.
(3) Methods of deratisation of:—
(a) Ships. The methods employed for the deratisation of ships are:—
(1) The burning of Sulphur at the rate of 3 lbs. per 1,000 cubic feet of space,
the period of exposure of vessels to the Sulphur Dioxide gas thus generated
being not less than six hours, and whenever time permits twelve hours or
even longer. Roll Sulphur, of good quality, is used, and is burned in large
shallow trays standing in larger trays containing water. Owing to the large
burning surface thus obtained, considerably more Sulphur can be burned in
one container within six hours than is possible when buckets or pots are used.
Cylinders of liquid SO2 (Sulphume) are employed in small compartments
and life-boats.
(2) The generation of Hydrocyanic Acid Gas by various methods. For the
destruction of rats a concentration of 0.2 per cent. of HCN is attempted,
and the minimum period of exposure is two hours. If the fumigation is for
the destruction of insect life, bed-bugs and cockroaches, two or three times
this concentration is employed and the exposure is twelve to twenty-four
hours, according to the time available. The methods of generating HCN
employed are the spraying of liquid HCN, the scattering of "Zyklon 'B'"
or "Celophite Units" and the pouring of liquid HCN into trays (Galardi
process).
"Celophite Units" are thin discs of wood pulp saturated with liquid
HCN. Each unit holds half an ounce of liquid HCN and they are packed
in strong containers each holding 32 discs. They provide an easy and