The Van Buren press., 1903-05-23
HOUSE FLY CARRIES DISEASE.
,,ex,,ratIou by Illinois Normal
school students Proves mis-
CJuclusiyeIy.

The house fly appears as a dangerous
and vicious insect, il the light ot the
Investigations aHd experiments when
have been made by Miss Eva May Shoe
maker and Alvin Waggoner, two stu
dents of the eastern Illinois state nor
nal school, working under the Gree
ton Of W. II. Manwaring, Of Johns
Hopkins university.
Their experiments seem to prove
the charge against the fly that
it is a carrier of disease. They have
shown how the fly, captured about
houses and in the open air, carries bac-
terra and how it can spread disease, re
ports the Chicago Tribune.
Their endeavor was to determine the
part the fly plays in the transmission
of bacteria.
To do this they constructed piece
Of apparatus consisting Of box dl-
,Ged into TWO compartments. In the
first compartment they exposed food
material infected with an easily rec
ognizable species of bacteria-narm-
| less bacteria, Of course, being used
| and in the second compartment they
placed an open Petri dish containing
sterile nutriment-agar. a culture me
dunn for bacteria. Flies were placed
in the first compartment, and as soon
| as number Of them had been seen to
walk upon or eat the infected mate
rial they were allow ed to pass through
a small door into the second Compart-
mcn;, where they had a chance 10 come
into contact with the agar in the Petri
dish. Bacteria, deposited on the sur
face of the agar, multiply there and
| form characteristic colonies.
In the preliminary experiment, per
formed July l6, yellow bacteria was
used. Molasses mixed with a growth
of this bacterium was spread on
| plate in the first compartment, and a
dozen flies put into !Le apparatus.
Half an hour later tEe door between
| the two compartments was opened and
tn. flies allowed TO pass through, As
|
come in contact with the agar in the
| Petri dish the dish was covered and
put away TO develop. A few days later
there had grown on the agar over a
hundred colonies Of yellow bacteria,
They repeated this experiment with
red and violet bacteria. and obtained
characteristic red and violet colonies
TO prove that the germs from which
| these colonies grew came from the in
fected material in the first compart-
meut and not from accidental sources,
control experiments were made with
| other groups Of flies, but with no in
fected material in the first compart-
mcut In no case, however, did the
Petri dishes used in these control eX-
perimeuts develop yellow, red or violet
colonies. TO prove that the flies were
the only means Of transmitting the
| bacteria, experiments were made with
| infected material in the first COmpart-
| mcut, but with no flies in the appara-
| tus. The Pctri dishes from these eX-
| perimcutS also developed no colonies.
The germs that grew into colonies in
| the first experiments, therefore, came
from the infected m&tcriaI ia the first
| compartment and were carried TO the
dishes by flies. From these results
they drew the more general conclu-
sion that flies are capable Of carry
ing bacteria from one place toauother
| If they have a chance 10 come in con-
tact with material coutainiugfhcSe or
ganisms,
They next undertook to determine
"whcthcr flies in nature actually do
| carry bacteria with them" "To de.
terniue this, test tubes Of sterile agar
| were melted and then cooled TO 40 de-
grces C., temperature a little above
that Of the human body, At this tenn
peraturc the agar still remains liquid,
| but H. not hot enough 10 Nil bacteria.
| Flies were caught with sterile forceps
| and washed in this melted agar, The
agar was then poured out into sterile
| pctri dishes, where it SoIidihed, ,, 1t
| is reasonable 80 suppose that If hac-
terra were present ON the flies some Of
them at least would be washed uN by
this process into the agar, where they
would multiply and form colonies
The dishes obtained from these eX-
pcrimcuty varied greatly but all Of
them developed colouic, ranging from
30 TO over 1000 Flies in nature, there.
fore, pnubuuly always 90 carry bac'
terra with them,
From the standpoint of public by
giruc these conclusions are sigrih-
cant; for, admitting that flies can
carry harmless bacteria, there seems
10 be no reason why they cannot carry
disease producing bacteria as well In
| fact. II has been a genera, belief among
scientists for number Of years that
| they are active agents In the trans
mission ~ many diseases, Recent
studies by Dr. h. o, Howard on the
breeding habits of these insects fur.
uish good evidence that they OCCASION.
ally play an important role In the
transmission Of typhoid fever, II is
probable that they c0u, and do, carry
the germs ~ any disease which offers
them an opportunity TO come in con.
tact with infected material
Sudden Drop.
"Ncp," said DUkota Dan, resting his