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3. Garden tanks.—These should be erected according to the necessities
of a garden and not the comfort of the "mali". They should not be sunk in
the ground, and the water tap in connection with them must always be
inspected and show no leakage. They should be built of bricks and concrete,
and plastered all round and should have an opening at the bottom to clear out
all possible traces of water and thus allow of thorough scouring. Fish for these
cannot be advised, nor a wire-meshed netting, as this will soon get damaged.
Putting kerosine on top is no good too, as the wind carries it all to one corner,
and forms blebs leaving a greater part open, in which larvæ do live and thrive.
"Whenever there are more than two such in a garden they should be periodi-
cally dried in the sun every 8 days. Fountains may be stocked with fish of a
suitable kind.
The general measures for garden tanks, fountains, cattle troughs, etc., are :—
A. A license and periodical inspection.
B. Cleaning and occasional drying.
The plot of ground around these should be always kept dry and never be
allowed to get water-logged. These wells and tanks can be rendered innocuous
at little expense and should remain so.
Garden drains.—Of these there should be always as few as possible and
all should be brick-built and well levelled to allow no pools of water in their
course. They should not pass close to a house, The pernicious habit of
allowing a constant flow of water to pass through them and soak plots at
leisure must be steadily discouraged. They should be thoroughly swept out
and allowed to dry (most of these water-logged areas breed Anophelines).
Garden tubs should be periodically emptied and scoured.
Drains and gully traps should be inspected every 8 days and the traps
pesterined.
II When we come to consider the temporary breeding places, the out-
standing difficulty is the insufficient supply of water to every house, and the
consequent necessity of storing it in receptacles according to the means of the
tenant. Gharras, tubs, soda-cooling chatties, flower pots, antiformicas, fire-
buckets, etc , must all be emptied out in the presence of the inspecting staff.
Large sizes should be steadily discouraged. Disinfectants cannot be used.
A. i Supplying taps to every house.
ii Periodical inspection every 10 days.
iii The breeding of larvæ on the premises must be dealt with as an
" offence " and should entail a penalty.
iv Erecting and keeping under control experimental breeding
grounds.
All collection of waste water, round stand-pipes and in hollows of masonary
works of tanks, and around the mouth of wells, should be carefully inspected
and promptly filled up. Solid surface drains should be constructed to carry off:
all waste water.
The killing of the residual adult mosquito appears an entirely unnecessary
measure, provided that a locality far and round is kept constantly under control.
If necessary, as in holds of ships, sulphur should be burnt in a closed space—1 1/2
1b. to every 1,000 cubit feet of space.
Special traps :—It must be remarked that it will not be sufficient only to ins-
pect and cleanse the temporary breeding places of S. Fasciata. There are millions
of adult mosquitoes existing, and as soon as their favourite haunts are abolished
they will seek other suitable locations and in the absence of these, such unusual
places (in Karachi) as wells and garden tanks, cess-pits, etc. This being the
case it will certainly follow that any well, etc., in the neighbourhood if not
already infected will speedily become so. Starting, therefore, with the premise
that the present temporary breeding places are well under control, a special
catch-place, as a tub full of water, should be prepared for them. These should
be located in every group of 50 or 100 houses. They are in no case to be
touched but for the emptying and cleansing of them every eight days. These
will serve to attract the flying adults and induce them to lay their eggs therein.
H 305—6