Evening star., 1909-08-30
New Agent of Disseminating
Bubonic Plague Found.
SUSPICION FOLLOWED UP
Investigation by Surgeon Blue Of
Marine Hospital Service.
DANGERS MENACING HUNTERS
Experiments Tried With Gases and
Poisons for Killing the Little
Disease Carriers.


dying hard and there has now been dis
lowered another agent in the spread OF
the infection that is even more insidious
and difficult TO deal with than the rats
that for a time threatened San Francis
CO and the other large cities. They are
the ground squirrels that seem TO have
become particularly infected in Contra
Costa county. and which, ii given tie
chance, will spread the infe ction through
out the west.
The ground squirrels have long been a
nuisance on the Pacific coast. and at va
rious times have caused considerable dam
age to crops. While some OF their rela-
tives, the field mice, have made havoc in
the alfalfa lands farther west, the squir-
rels have been regarded as good eating
up to recently and there has been
quite trade in Killing them
for market, while in the reg ons wnere
down in large quantities for winter and
have regarded their meat as staple ar
t.cle of dict. 1t was noticed during tie
earlier part Of the crusade against p ague-
infected rats in San Francisco that the
ground squirrel could be infected by the
anne flea which caused the spread of the
bubonic plague among the rats. AS early
as 1908 the case of one man was noted III
Contra Costa county who died of the
plague without having been in any of the
larger towns, but who was known to have
been hunting ground squirrels.
Squirrel Under Suspicion.
Surgeon Rupert Blue of the marine hos
pital service noted this case, and as
other cases developed, suspicion was more
and more directed toward the squirrels
First boy who had been hunting them
and several other men were attacked by
the plague. and finally an examna-
ton was made showing conclusive
ly that the squirrels were the hosts Of
the plague-producing flea. From this
time on a war was waged against the
ground SOU rrel and now regular ship
ments OF them are made to the laboratory
of the marine health service In San Fran
ci co, where they are examined as care
fully as are the rats when there is a
suspicious outbreak OF plague. There
have been a hundred and seventy-eight
infected squirrels d scovered, and this alone
shows the danger that the hunters run in
the specimens. All possible pre-
cautions are taken and the squirrels are
placed In bags, where there is chlofoforln
TO XII or at least stupefy the fieas be-
fore they are put in Theoretically sealed
cans to be shipped to the laboratory The
hunters are also warned Of the danger
they pun and many OF them are provided
W1n an lmnlunizlng serum, which they
nave taken as a precaution against the
d sease, and none of them is ever allowed
to reach down in the burrows after sauir-
reis that have been wounded. They are
provided instead with long-handled hooks,
with which the squirrels arc hauled out.
Killing the Squirrel.
Experiments have been tried with all
sorts of gases and poisons for killing the
anr,a
agents is carbon bisuphide. This Is used
on balls of waste that are showed into
the burrows and the holes closed to allow
the spread Of the gas through all Of the
underground passages.I The LIQUID Is
highly explosive under certain conditions
and cne method of using il is in paper
shells lightly packed with waste and hav-
ing two wires. the ends of which are
placed together like the spark plug in an
automobile. Several of these shells are
placed II different parts of u warren ard
are fired simultaneously by an electri,
current. The shock of the explosion is
almost sufficient to kill the squirrels. while
the poisonous gas completes the work and
also kills the feas. pne objection TO the
use of carbon b.sulpnide Is that it is
rather expensive.
Another agent that has been used Is
hydro Genie acid gas. This is compare
lively cheap. but It Is extremely danger
Gus except in the hands of experts. Small
tins Of sulphur acid are placed in the
burrows, all the entrances but one closed
and then a sma ] paper bag of potassium
cyanide is dropped into the acid to gen
crate the gas. This also kills the f1eas
and in fact anything else that happens
to he in the warren.
Experiments have been made with ap-
paratus to pump poisonous gases into
the squirrel burrows. but nothing thor
oughly satisfactory has yet been devel-
oped. PO son has heen used to large
extent and there have been extensive
squirrel bat.eaus like the rabbit killings
in Australia. and the squirrel population
in this particular county. which covers
about 1GD square mics, has been largely
reduced