3
The quantities of acid required to be carried in operations such as these were
against this process, but the action is distinctly rapid. The house was then left
undisturbed for 6 hours.
In each cart were also a number of powders marked " For disinfecting,"
these consisted of 280 grains of perchloride of mer-
Disinfection by spraying. cury (HgCl 2 ) with sufficient salt, to render the mercu-
rial salt soluble in water on being added to the pails used. These powders con-
taining 2 gallons, gave a solution of 1 —1,000. By means of these the thorough
disinfection of houses and contents was carried out. One ounce of the salt will
disinfect over 3,000 square feet at a small cost. On a case of plague being re-
moved the bedding and any other garments soiled by discharges, &c., from the
patient were burnt in the street and the remainder left in the house. The whole
interior and contents were then thoroughly washed down and soaked with the
perchloride of mercury solution by means of Chinese wooden hand-pumps,
which gave an efficient spray of considerable force, and being made of wood,
were not acted on by the salt or mercury. As, at the time it was impossible to
procure wooden pails and the mercury from the perchloride was deposited on
the metal, corroding it and also rendering the solution inert, the interior of the
galvanized iron pails used were coated with a layer of white paint which entire-
ly obviated this difficulty. In some instances a 5 per cent. solution of carbolic
acid was used, the crude acid being made mixable with water by the addition of
soft soap. This was the method chiefly adopted in the Cantonment; but of the
two processes the perchloride is undoubtedly the one mostly to be relied upon,
being more cleanly to use, easier to work, and less expensive. All that is neces-
sary is to have the powders containing the perchloride ready mixed with some
chloride, such as sodium chloride, the least expensive ammonium chloride, &c.,
which renders it soluble, and the powders are thrown into the water and used
at once. The wet method by spraying over the gascons has the advantage,
that every nook and cranny can be reached by the solution, which is thrown
with considerable force, all articles being soaked by it are penetrated and the
germs destroyed ; whereas in fumigation the more resistant germs, and those
not freely exposed, lurking among the folds of cloths, behind partitions, &c., are
not reached by the gas. The objection of having to close up the house and
render it air-tight is also obviated. In the class of house in Poona where the
floors are chiefly composed of cow-dung, the penetration through the floor is
considerable, although some of its effect may be lost by contact with organic
matter throwing down an inert precipitate. The proportions suggested by the
Local Government Board are ½ oz. of mercuric chloride, 1 oz. of hydrochloric
acid and 5 grs. of commercial aniline blue in three gallons of water, costing
about 3d. At first this was the basis of the solution used in Poona, but it
was found inconvenient to carry the hydrochloric acid and so a chloride was
substituted, which answered all requirements.
II.—Lime-washing.
All houses after disinfection were thoroughly lime-washed inside, and for this
a mixture of half quick-lime, care being taken to use
Lime-washing. only the best, and half chloride of lime, was used.
An effort was made to lime-wash all the houses possible in such a large area
(four square miles), and especially those which had been shut up on the in-
mates fleeing the city and which, there being no means of telling, were possibly
many of them, infected houses, the cases having been removed. On return o£
the people there was danger of re-infection from this cause.
There were organised three divisions of lime-washers of ten parties each,
a party consisting of one European and three Native Sappers, under an officer
and with an equipped transport of 30 carts. A daily list of houses to be lime-
washed was supplied to the officer in charge, and the parties worked a day
behind the search parties and disinfectors.
All rubbish found in the houses, especially old rags, numerous in every
house, were burnt, but no property of any value was destroyed, except under
the directions of a Medical Officer. After carefully lime-washing the interiors
the floors were dug up for a depth of four inches and saturated with a solution of
chloride of lime in water ; all privies attached to the houses were similarly treated.