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12
Medical Officers of the Ministry of Health in the pros ana cons of the matter of
preliminary fumigation and subsequent precautions against the change from the danger
of the living poison of the plague bacillus to that of hydrocyanic acid fumes. This
preliminary fumigation would appear to have been nearly successful in exterminating
the particular vermin concerned in Plague spread on board, both fleas and rats. In
connection with the fleas, it is to be noted that they are more susceptible to the poison
than rats, being killed in a shorter time and with a lesser lethal concentration of
hydrocyanic acid in the atmosphere.
Between the Friday fumigation and the starting of work on Monday there was an
ample airing of the ship, but Mr. Wilton, of the Fumigation Services, Ltd., whose
expert handling of the fumigant has been of the greatest use to this Authority, carried
out such stringent tests continuously during two days of working of the cargo as
showed that safety had been assured. At the second and complete fumigation, when
the vessel was discharged, only five rats were found. The history of the total rat
population of this ship is shown in the appended list below.
The cargo of the ship consisted of pollards, flour, wheat, linseed, maize and
semetin in bags and wheat and maize in bulk. The number of dead rats found
immediately before the preliminary fumigation, death being attributable to Plague,
was 35, this constituting the definite evidence of mortality.
History of Bat Population.
On arrival 30 caught at sea (reported).
„ 35 found dead—result of search after partial discharge of 'tween decks (bagged
cargo).
1st July. First Fumigation.
4th „ 11 in bunkers. Brought forward 250
66 in holds generally. 9th July 5 in bilges.
22 in poop. 2 in poop.
5th „ 46 in holds generally. 9 in holds generally.
7th „ 1 in bunkers. 11th „ 14 „ „
19 in holds generally. 12th „ 11 in Nos. 4 and 5 holds.
8th „ 6 in poop.
14 in holds (deep down).
Total 291
Carried forward 250
13th July. Second Fumigation.
2 in bunkers.
3 in after-hold.
Total 5
The special points to which I would draw attention are the value of examining
ships on commencement of discharge of cargo as to rat mortality—a routine in the
Port—the value of a preliminary fumigation as a safety measure for workers and
prevention of spread of infection in the Port, and the suitability of hydrocyanic acid
for preliminary fumigation in selected cases. This ship and her circumstances
constituted a favourable case for preliminary fumigation and successful results
therefrom.
Some suspicion fell on three grain ships arriving subsequently from the South
American coast, and special precautions were taken, including a preliminary
disinfestation on two of these; the suspicion was not confirmed.