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The total number of persons cleansed during the year was 5,287 ; the total cleansings numbered
6,927. This shows a considerable increase over the figures for the previous year, which were 4,029
and 5,658 respectively.
The clothing worn by persons on their visit to the medicinal baths is disinfected, together with
such other articles of clothing as the patients may bring. Altogether 16,031 articles were so dealt
with and, in addition, 449 blankets and sheets, and 357 articles of night clothing.
Of the 4,337 school-children cleansed at the medicinal baths, 534 were compulsory cases ; the
remainder attended voluntarily.
Disinfestation.
The activities of the public health department in regard to disinfestation may be divided into
two branches. The first is the treatment of vermin-infested houses, and the second the treatment
of verminous furniture.
Treatment of Verminous Dwellings.
For some time past the officers of the department have been actively engaged in the search for
a method of house disinfestation which would be cheap and successful, but safer than the application
of hydrogen cyanide. Various substances have been experimentally applied, and a highly effective
method of treatment has been evolved with the use of a substance known as washed heavy naphtha.
This substance is a complex mixture of aromatic hydrocarbons with their associated bodies, and
the major constituents are pseudocumene, mesitylene, tetramethyl-benzene, cumarone and indene ;
small amounts of naphthalene, thiopen and methylpyridenes are also present. The constituent,
or mixture of constituents, which is lethal to the bed-bug is not at present known. Pathological
tests carried out at the University College Medical School indicate that danger to man from the
use of the substance is not to be apprehended.
Washed heavy naphtha is simple to apply, and the method adopted for house fumigation is
briefly as follows :—The house is pre-heated by means of portable primus stoves. The windows,
fire-places, etc., are sealed with a stout paper. Then, in order to counteract any loss of vapour
by diffusion through the fabric of the structure of the dwelling and by absorption in building materials,
screens of cotton fabric are fixed right round the rooms of the dwelling. Furniture is brought away
from the walls and the whole of the cotton fabric thoroughly wetted with the naphtha, which is
applied with a knapsack spray. The house is kept sealed for 24 hours, and then ventilated. The
rate of desorption of the vapour is rapid, and the rooms are fit for habitation after being ventilated
for a few hours.
The number of premises treated with naphtha during 1937 was 373, the total number of
rooms being 1,069. Ninety-four borough council houses were treated with naphtha.
The results appear to be satisfactory, and only in 27 cases was a second application necessary.
These failures occurred chiefly in the early days, while the technique was being perfected.
The council's clearing house at Seymour King Buildings was used to re-house temporarily
families displaced while their houses were being treated with naphtha. Altogether, 101 families
were temporarily re-housed in this way.
The treatment of slight infestations.
The council do all in their power to help persons who find that their houses are slightly buginfested,
and the council's workmen treat such premises either by burning sulphur or, more
frequently, by applying a light contact spray. In some cases a small spray apparatus charged with
insecticide is loaned to poor persons, and instruction is given in its use. During the year 494 premises
were treated with sulphur or with a light spray, 832 rooms in these premises being affected; and
1,024 articles were taken to Wood Lane to be treated in the steam disinfectors.
Treatment of houses to be demolished.
When houses are demolished the woodwork frequently finds its way, either as firewood or for
repair purposes, into other houses, and thus vermin may be carried unsuspectingly from condemned
houses to houses hitherto free. To avoid this possibility all infested houses are disinfested by
thorough application of " Keritox " prior to demolition.
The Disinfestation of Furniture, etc., with Hydrogen Cyanide.
The method introduced in the borough in 1934 to prevent the transference of vermin from old
vermin-infested houses to new housing estates continued in operation throughout the year.
All families who are allocated flats under rehousing schemes are notified that fumigation of
their furniture must be carried out before they can take up occupation of their new homes.
On the day of removal a specially constructed steel van arrives at the old home about 8 a.m.
when all furniture and effects are loaded into the vehicle, which then goes to the council's Wood
Lane depot. Bedding is removed from the van for disinfection by steam, after which hydrogen
cyanide is applied to the contents left in the van. The gas remains in contact with the furniture
for two hours and the process of extraction is then put into operation for four hours. Tests are
made to ensure that all the hydrogen cyanide has been extracted, after which the furniture and
bedding are transferred to the new home. The entire process of removal and fumigation is
completed during the same day so that the family experience no inconvenience. There is an
exception, however, in the case of upholstered articles, which are retained overnight in a warm,
well-ventilated room ; this is done because it has been found difficult to render these articles
entirely free from all traces of hydrogen cyanide in four hours.