The Leavenworth echo. [volume] (Leavenworth, Wash.) 1904-current, 1909-08-13

strychnia sulphate and distributed ovel
all the ranches at the same time, effect
lively disposed Of the problem. The
experiments also showed that similar
plaques could not alone be wiped out
once they had started, but could be
controlled in the beginning.
On two ranches seven to fifteen men
were employed distributing the poison
with most satisfactory results and with
out the dangers incident to the distrib-
ution Of the phosphorus-poisoned grain.
Il was found the salaries and expenses
Of the men were a mere bagatelle COM
pared to the results accomplished by
their labors in wiping out the pest.
These experiments were undertaken
in January, and by March IS poisoning,
supplemented by the work Of predatory
birds and mammals during the winter
months, had destroyed the mice on
several thousand acres where they had
been most abundant at the height OF
the plague. By May the mice which
remained in small numbers in scattering
centers were found to be steadily de-
creasing, and later in the summer had
practically disappeared from the valley.
The species of mouse responsible for
the plague is the one known locally in
the West as the black mouse" Sci
entists have given it the name Of Car
son field mouse-Microtus montanus.
The Humboldt valley plague shows
where conditions are exactly suited to
their sudden and enormous increase
these mice may at any moment become
the source of great trouble to farmers.
The Biological Survey expects future
and more disastrous outbreaks as the
West is settled and the large areas, on
which the mice are now able to sub
sist, become filed with fields of their
favorite food.
Strychnine, phosphorus, lead acetate,
mercuric chloride, and arsenic in its
many compounds were tried. Every
test gave strychnia sulphate as the best
poison and the most practicable for use
against the mice. Directions for pre-
pairing alfalfa-which was found to be
the best vehicle for the poison, and at
the same time the best bait for the
mice-in strychnia sulphate were given
by the experts of the Biological Survey
as follows:
"Poisons should always be prepared
at a distance from the house, where
stock and poultry are not endangered.
To avoid danger to persons, strychnine
and the vessels in which it is used
should be carefully handled and safely
stored away when not in use. Ordinary
fve-gallon oil cans, for which covers
and wire handles have been provided,
make excellent utensils. A fire hole
about two feet long and foot wide,
over which two iron rods are placed to
support the cans, makes a fireplace
where the solutions can be quickly pre-
pared. Galvanized iron wash tubs are
suitable for mixing the material if grain
be used. For preparing alfalfa on the
large scale usually necessary, a large
metal receptacle which will permit the
mixing of thirty pounds Of hay at once
is required. One or two oil cans marked
in gallon measures, a sprinkling can
and several large, strong spoons com
plete a handy outfit for preparing the
mouse poison.
A single treatment OF alfalfa hay SO
poisoned resulted in the death of from
IS to 95 per cent of the mice in each
field treated. The hay used was fresh
and green rather than bleached, and
was either chopped or the fine material
from the base of the stacks was used.
The formula used was as follows:
Chopped alfalfa hay 30 pounds
Strychnia sulphate ! ounce
Water - or E gals
When properly soaked in the mixture,
and the hay saturated with the solution,
it may be taken up and sacked and
stored away; though results are better
where only enough Of the preparation
is made at a time for the immediate
needs of the poisoning squad.
1t was found to be best distributed
by hand, placing small pinch, say a
near the entrance TO each
burrow, and scattering little here and
there along the surface trails. In cold
when the mice remain most of
the time under ground, it should be
dropped inside the entrances Of the
burrows. 1t is estimated about 40 per
cent of the mice which eat this poison
die on the surface, the remaining 90
per cent perishing in their nests. The
amount OF strychnine in the alfalfa is so
small that danger to cattle is practically
eliminated, and no trouble was expert
enced from this source in Nevada.
In the Carson valley in April poison
ing with green alfalfa was found most
successful. The mixture used there
was as follows:
Green alfalfa As pounds
Strychnia sulphate ounce
Water ------- IL gallons
l