Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-04-04
SEEKING RAT DISEASE
NOT TO CURE, BUT WITH TIL
IDEA OF EXTENDING 1T.
Scientists Aiming at Rodent Exter-
mination by Means Of an
Epidemic.

DSpot tuCHt VI <ASTlCullufe DeileVS tuSy
have found disease that will spread an
epidemic among rats. This is too large a
subject for them to make any decided
disease germ had been captured, and its
efficacy is only a matter of further demon
stration
Many people may want to know why the
government is anxious at all about pro-
pagating q disease among rats. But II
one stops to think of the millions Of dollars
worth OF damage done by rats each year,
not only to grain stored in granaries, but
to household goods. stocks of all sorts In
stores, the spread of disease and the de-
struction of young poultry-for this. too Is
method of killing of rats wholesale would
be worth an incalculable amount Of money.
Experiments in Australia.
The biological survey has been working
on the problem for number of years.
hunting for an epidemic disease to spread
among rats. and also something that will
kill off rabbits. gophers and other vermine
that bleed the farmer every year. Other
governments are on the trail Of the same
sort Of germs. and the government of Aus
tralia has paid enormous sum to DR..
Dansyz Of Paris to experiment with rabbit
diseases for the next four years, II he does
not succeed in his work sooner. At last ac-
counts it was believed that he had some
was likely to prove success. 1t is easy
to see that If an epidemic can be started
In any locality among the animal pests 1t
beat any sort Of poison or traps for killing
them off.
AS a rule disease that affects one spe-
cies of animal has no effect on another.
But in the present case the disease with
which the department is working was first
discovered among the squirrels. 1t was a
pure experiment to try 1t on the rats, but
it seems to be deadly to them also The
history of the disease is in itself rather ro-
mantle, for it lay dormant in laboratory
for almost decade before it was brought
to light and fresh experiments made
with it.
Germs Preserved for Years.
1t happened about ten years ago that Mr..
s. E. Piper of the bureau of plant indus
try of the department was working out in
Washington and noticed an epidemic among
the squirrels. Nature seems to take this
way Of clearing out an animal colony when
1t gets too numerous and such outbreaks OF
diseases are happening all the time In one
part Of the world another. but 1t is
usually too late when the scientist hears Of
it and gets to the scene OF the epidemic.
But in this case the scientists noticed the
outbreak where they were working, and
while this sort Of thing was not exactly in
Mr.. Piper's line he recognized the value Of
1t and set to work to propagate the germ.
Cultures were made and some experiments
tried and little field work was done, but
not much as the experimenters wished.
Some of the germ cultures were sent to
Prof Theobald Smith of Harvard, formerly
of the Agricultural Department, who want
ed them to work with apart entirely from
their possible value an animal extermina-
tors. When the search OF the department
for q " PiDpr a
brother of the gentleman who had orig
inally discovered the disease, communicated
with Dr. Merriam and DR.. Henshaw, the
scientists of the biological survey and sug-
gested the possibility of tracing up some of
the old germs. OF course the supply Of
the original investigators had long ago been
destroyed but there was a possibility that
Prof Smith still had some, and on applying
to him it was found that he had some Of
the cultures still, having kept them alive
all these years by occasionally transferring
them to new culture media.
Disease germs under these circumstances
largely lose their virulence. But strangely
enough when they are run through the
bodies of few animals and fresh cultures
made they regain their strength. This was
done and it was necessary to put the germs
through six or eight successive animals be-
fore they regained their former strength.
But after this was done it was found that
the disease was just as deadly as ever. 1t
is believed that the disease is contagious
as we'll as infective.
Tried on Rats.
Then it was thought to try the disease on
rats and to the surprise of the scientists,
1t was found to be equally deadly with
them. The experiments along this line have
not advanced very far and there num-
Der of rats under observation in all stages
of the epidemic. Healthy and uninoculated
rats are being kept with some of the sick
ones to see whether the disease Is really
transmitted by contagion.
One thing that has handicapped the work
a good deal Is the scarcity of live rats on
the Washington market This seems almost
unbelievable, but although there are armies
of rats in the city and there are plenty of
dead ones killed in traps and by poison,
healthy live rats have been very hard to Sc
cure. The department has had to pay as
high as 10 cents each for them, but the
price has gone down recently.
1t will take great deal Of experimenting
before the disease, If 1t proves suitable.
will be ready for general use. Many things
have to be guarded against in turning loose
an epidemic Of this sort and every precau-
not only will do its own work, but that it
will not infect domestic animals, as is the
case with some otherwise desirable germ
diseases. However. the officials of the
biological survey believe they the
right trail.