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Although cow-dung is present in most of the houses in this "Ward there are a large
number of houses whose interior lining is of wood, koba or cement, corrugated iron. These
substances do not require to be treated with the same strength of the solution. The
plague organism has feebly resistant powers to weak solutions of the Perchloride.
Provided that these materials are well scrubbed of all superficial dirt, a weak solution
would serve every purpose of disinfection. I would therefore advise a dilution of "the present
original solution when it is applied to substances other than cow-dung, earth and bamboo.
Cow-dung is known to possess a fair amount of albuminous coagulable material which
gives it that resistant and adherent property when spread over earth and dried. When the
sublimate is poured over a cow-dung floor, a tough resistant coagulate is formed as a pro-
tective covering to any further action of the germicide, on the material beneath. But the
very germicidal action of Perchloride of Mercury depends on its power to precipitate albumea.
By coagulating the protoplasm of the plague microbe, it kills the organism. As the
Hydrochloric Acid is the solution used it acts as a disintegrator and pulverizor, it is important
to use sufficient solution for the quantity of cow-dung to be acted upon.
Thus, in order to efficiently disinfect cow-dung it is necessary to bring every part of it
into close and intimate connection with the solution. To effect this a superabundance
of the solution should be constantly used. Further, it has been shown by experiment, that
10 cubic centimetres of a 1 in 725 acid solution effectively disinfects against plague 0'7
gramme of cow-dung, as O7 gramme -of cow-dung is the amount that can generally be
recovered from four square inches of a floor of a native dwelling, it follows that the floor
of a room measuring 10 ft. by 10 ft. ( a very small room ) would require 8 gallons of the same
solution. 8 gallons is over 3 bucket fulls.
The disinfection of a floor of a room of that size is manifestly costly.
Ke-infection is by far the most frequent in cowdunged earthen floored houses, for where-
ever cow-dung is found, there also are the following. ]
(1) Badly constructed houses, with ill ventilation, insufficient sunlight, improper drain-
age, and overcrowding.
(2) Abject poverty bringing filth and dirt in its train.
(3) Low caste people, who seem to be more susceptible to plague and have less
powers of resistance.
(4) Eats—With earthen floors, rats gain ready admission, and become free boarders.
They act in their turn as the hosts of
(5) Flea and vermin.
Cow-dung when old becomes very dry, and cracks, and fissures make their appearance.
From one of these about 2^- ft. long I turned out what appeared like several families of the
pédicule of course, one does not need to dig to find them, for they are as readily found some-
where much nearer within their hosts. But, while clothes, &c., are constantly being sub-
jected to the action of sunlight and water, the fissures in cowdunged earthen floors
harbour old and permanent guests, whose hosts are both man and rat. It is well known
.that diseased rats are often literally covered with vermin. I believe that plague bacilli have
been found in the intestines of a plague infected flea, and a bite from one of these would be
followed with just as certain results as would be expected from an actual artificial ino-
culation.
It -would be a wise measure to compel all huts to be floored with koba or even some kind
of rough cement. Such a measure is practicable, and I am confident, that when it is
established in Bombay, our disinfection would be more rapid, easier, cheaper and more
certain. Bamboo comes next in importance as regards liability to harbour dirt and filth.
It is a cheap article and is therefore always found in improperly constructed dwellings. It is
used chiefly in the construction of partitions of rooms and in the flooring of attics. It is now
a well recognised fact, that ground floors and attics have constantly shown a greater
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