CONTROL WITHIN THE HOUSE
Many minor plans have been proposed for obviating or alleviating the
perils and plague of invading fly swarms; several such plans may be well
carried out on a private domestic scale, but one cannot expect any of
them to be adopted universally. In domestic methods people will prefer
some one plan, some another, whilst some will not personally aid in the
work of fly destruction in any single way perseveringly. This latter
circumstance emphasises the necessity of a dominant control by local
authority for the safeguarding of all inhabitants, including the
delinquents themselves in spite of themselves.
The plan, as detailed in the last chapter, of enticing breeding females
to lay their eggs within depositories of discarded food remnants and
garbage, can be practised on a smaller scale with great advantage
everywhere. Kitchen refuse of many kinds, not neglecting potato and
turnip parings, cabbage leaves, or even tea leaves, should all be
collected in brown paper bags, which should be left open for a few days
in suitable places round about the house for the free access of gravid
female house-flies. Every such collection should he cremated on the
third day. In a paper, read at a recent congress of the Royal Sanitary
Institute, on "Destruction and Prevention of Household Pests," Dr. Gay
advised rich and poor, in every household, whether or not a sanitary
dust-bin was in use, instantly to _wrap up in paper_ all such
fly-breeding materials in readiness for cremation. However, to do so
would be missing the much more effectual course of applying my
"egg-trap" plan of collections in exposed _open bags_ for cremation on
the third day.
For indoor use insecticide methods are more suited; and the best of
these are immensely more effective than some popular devices, which make
a remarkable display and sell well, but which the purchasers soon become
neglectful to keep in constant use. Traps in the form of wire-gauze
cages, and glass non-return bottles belong to this latter class of
contrivances; when seen crowded with struggling victims, the employment
of such articles captivates many observers; but their real efficiency
will be found to fall far short of general expectation. The explanation
will be apparent when the use of the wire-cage trap is contrasted with
the success of a good fly poison. Given, say, a dwelling room on a
midsummer day containing ten female flies and ten idle dancing male
flies; in such cases not more than half the females and one quarter of
the males will get imprisoned within four or five hours by the
employment of the wire-cage trap, but with a good method of setting
poison nine-tenths of the females and half the males may be killed
within the same period. In the case of poisoning, the dead have to be
swept up, whilst fly traps have the advantage of collecting the victims;
but, unless the inmates are carefully destroyed, a few will manage
sometimes to escape from the traps, especially as side window light
changes and daylight fades. In these fly traps it is only the
perseverance of the prisoners in struggling towards outer light which
prevents their exit by the entrance aperture.
Stickfast adhesive papers and suspended tapes and strings look very
effective when seen crowded with accumulated captures; but, again, these
"exhibition" appearances are as deceptive in suggestions of real
efficiency as are the crowded cage traps last mentioned; moreover,
sticky messes are not commendable or convenient articles for placing
where most wanted. Truly, suspensory strings are attractive resting
resorts for dancing males, but the worst agents of Beelzebub are the
females, which have a keener appetite for food and for pestering
humanity.
There remain for consideration insecticide poisons. A great choice of
materials can be supplied by the chemist's shop, and various methods of
using them have been recommended. In old times country people prepared
decoctions of _Amanita muscaria_, the fly toadstool, a large
orange-scarlet, or crimson, mushroom-shaped fungus commonly appearing in
autumn in woods where birch trees abound. Strange to say, such decoction
will poison flies of many kinds, although they, and many different
creatures, feed with impunity on other fungi which are more deadly
poisonous to mankind.
Effective poisons are such good exterminators of flies, that the main
consideration is how to safely and most suitably employ them. There are
some people who have an invincible aversion to the mere thought of
poison purposely administered by way of food or drink, though possibly
they do not have an equally strong repugnance to the use of insecticides
used for stifling. However, one cannot help running counter to much
misplaced sentimental humanitarianism in some people on some subjects;
reasons and arguments will not move them, for they do not wish to think
otherwise than as their prejudices influence them. The house-fly is
itself a poisoner of our food, and it, or rather she (the offender being
nearly always female), is a more dangerous and a more subtilely baneful
enemy than, for instance, the human flea, which even the Brahmans or the
disciples of Buddha may kill.
Fumigatory insecticides, though occasionally useful, may be left out of
consideration in discussing the rival merits of means in a warfare
against the house-fly.
A liquid or moist food poison employed in a safe and effective way will
excel every other weapon of warfare within the house. One of the newest
recommended substances is formalin, which has the advantages of being a
disinfectant, a strong fly-poison not avoided by flies, and not
dangerous or attractive to domestic animals. A tablespoonful of (40 per
cent.) formalin should be mixed with one half pint of milk and water;
this, when exposed in saucers or shallow dishes, is said to be an
attractive and a fatal bait. It would be evidently dangerous and
objectionable to use some other commoner poisons in the same way; but it
is the opinion of some users that formalin and milk is not sufficiently
alluring.
Contrary to a generally prevalent idea a powerful odour is not required
as an indoor allurement for the common house-fly; again, a saucer or
shallow dish with liquid contents is not a good _method_ of presenting
the fatal bait. Placed on a table, or on a window sill, or on a shelf, a
saucer is liable to be tipped up and its contents spilt; moreover, the
form of such receptacles is radically faulty by reason of the strenuous
walking habits of the fly on the level. Out of many flies walking over a
table ten or twelve may pass by, or round, an overhanging saucer's rim
to one fly that will mount the same and sip inside. However, let such a
saucer or plate be placed on a table upside-down, and let a slightly
moist substance be placed in the shallow central depression, which
ordinarily is the base, then the said ten or twelve flies will all mount
and sample the moist substance, even though it be not apparently
attractive in smell; an inclined plane is ever an irresistible
invitation to mount and prospect the summit.
It is another great mistake to suppose that an extra tasty food material
is desirable as a bait. The same kind of mistake is made by people
baiting a mouse trap with toasted cheese, whilst a bit of dry bread, or
better still, a green pea, would much better entice a common mouse.
Strong smelling and saccharine foods immensely attract the blue-bottle
and the wasp, which are thus enticed indoors and induced to become
occasional visitors to our tables; but the house-fly requires little of
such lures; indoors she is an inquisitive prospector, who will never
pass by any moist material without testing its quality. Moreover, the
use of poisoned milk, or even jam, should be rather avoided for fear of
injury to dog or cat; furthermore, it is dangerous to place a piece of
bread in a saucer of liquid fly-poison, as is sometimes done, to serve
as a sop and as a standing stage. However, there is one good lure well
worth mentioning; it is beer-dregs with or without a little sugar;
moistened yeast is good, and the advantage of beer-dregs with just a
little sugar is due to the mild yeast-like odour of slow fermentation,
which may fail if formalin be the insecticide ingredient.
The handiest and safest preparation of fly-poison is that sold in the
form of a dry flypaper, which is said to contain arsenic as the deadly
ingredient. A very small piece of one of the sheets ordinarily sold
should be placed on the summit of an inverted saucer; a mere spoonful of
water now and then will suffice to moisten the same; there is little or
no advantage in sprinkling a little sugar thereon, unless beer-dregs are
added. This plan of using moistened poison paper is clean; it is safer
than using a more fluid bait, and the ingredient is certainly efficient;
the slightest taste thereof by an inquisitive fly ensures its speedy
death. Another poison which has been recommended is a strong decoction
of tea-leaves, to which a little sugar and beer may perhaps be added.
It is said that the smell of geraniums is odious to the house-fly, and
so pots of these plants may be grown beneficially on window-sills.
Certain other odours and scents are believed to be likewise more or less
fly deterrent, but their use is not effective warfare against fly
propagation. Paraffin painted on window-sills is said to be very
efficient.
Flies may be easily prevented from entering the open windows of any
room, which has windows only on one side, by the use of venetian or
louvre blinds or shutters, or of many kinds of screens, although the
apertures thereof may allow of ample room for flies to pass to and fro.
If, however, there be windows on two sides of a room, then venetian
blinds and the like will be useless, and window screens must have very
close meshes to be effective. The house-fly will pass through netting
only when there is light shining on the further side. A knowledge of
this fact is very important in the planning of hospital wards. In a sick
room, if there be windows on two sides, one in summer time should be
darkened when the other is open for ventilation.
The protection of the larder and the screening of food should never be
neglected, but what is of even greater importance is the prevention of
access by flies to fæcal matter, or to purulent and all unhealthy
discharges from the sick room.