The Columbian. [volume] (Bloomsburg, Pa.) 1866-1910, 1875-08-27
The Mission of the House Fly,

The fly when it alights rubs its hind legs
together; then each hind leg is passed over
a wing; then the same operation is perform
ed with the fore legs; and then, if you will
observe closely, you will see Mr.. Fly pass his
trunk or probocis over his legs and about his
body as far as he can reach. The trunk ter
| inmates in two large lobes which spread out
| when the insect begins a meal, and is capa-
BILE of being drawn back rapidly; but though
| thus constituted it is not fitted for licking,
but simply for grasping and drawing up food.
What the fly does by flying around and then
alighting and going through the man@uvers
described has at length been successfully in
vestigated and decided by an English chem
&st named Emerson, who carried out his work
by the aid of 4 powerful microscope. He
relates that when he first conceived the idea
of making the investigation he captured
fine specimen and glued its wings down to a
microscope slide. On placing the slide un-
der the instrument he found to his disgust
that the fly appeared to be covered with ver-
min. He tried several others, which were
likewise covered with lice, and this curious
coincidence led him to still further investi
CATION. Why were the flies thus afflicted, or
was it an afiliction? Watching one of the
flies fastened on the slide more closely he OBJ
served the creature extend its probocis and
sweep it over its body, as ifit had just alght-
cd. Wherever the lice were the trunk went
they were disappearing within its recesses;
the fly was actually eating theml At first
he thought this vermin the hy's progeny, but
further investigation dissroved this.
Mr.. Emerson took piece of white paper,
on which two flies had alighted and were
licking themselves, and putting it under the
instrument found some of the little creatures
had fallen ofl-crumbs from the table, 50 to
speak. lie then took the paper, went into
tho kitchen and waving it round his head
taking care that no flies touched it during
the operation, went back to the microscope
and there found animalcule3 the same as
those found on the flies. Here he had some
thing definite. They were not the prog
eny of tho fly, but animalcules floating in
LHS all ihC bpul Vi tiS ny II NONClcu WIN
coarse long hair, and its quick motions
serve to take them up, as the hairy mouth of
the whale takes up the animalcules of the
sea. When he gets the net full the fly re-
tires to his favorite recess on the window sill
or in quiet corner, and then proceeds to de-
deyour his least of soft-shell crabs. Mr..
Emerson continued his investigation in va
riety of places, and the more dirty and filthy
the place and the more fGtd the odor per-
vading it, the richer the harvest he found the
flies had made in the animalcule line.
While the flies captured in such filthy
places were usually fat, and plethoric, and
happy, the flies found in clear and well-ven-
tilated apartments were so lean and misera-
BILE that when a spider caught one Of them in
his "parlor" he Immediately kicked it out as
not fit to eat. Wherever filth existed, evoly-
ing germs that might generate disease, there
Mr.. Emerson observed the flies were most at
tracted, and there they covered themselves
with the minute organism which they greed |
lily deyoured. From this can be deduced
the conclusion that while the mission of
house flies is one of immense Importance to
man, their presence in immense numbers,
while it indicates unhealthy exhalations, also
guarantees Immunity from disease to some
extent. OF course the house fly which has |
penchant for bald heads, and lights on the
skin only to punoture it and draw blood is
not here taken into account Such flies
should not receive any credit, even if they
deserve it.