Evening star., 1923-12-02
Dealing Death to Mosquitoes
BY FREDERIC ]. HASKIN-

that It imposed a fine of 81 upon any
person convicted of killing bat.
Additional bat roosts were then
erected by the state of Texas at the
Southwestern Insane Asylum, just
outside of San Antonio, and one upon
the campus of the West Texas Mill
tary Academy in the Alamo Heights
section. AS a result. large areas were
freed of mosquitoes.
Credit for the discovery of this
amazingly cheap and effective method
of combating mosquitoes belongs to
DR.. Charles A. r. Campbell of San
Antonio, a specialist In malaria and
typhoid, who has become known as
"the apostle of the bat roost." He
made. his first experiment early in
Mitchell Lake district, 10 miles from
San Antonio. AS this lake receives
the sewage from San Antonio, 1t is
generously supplied with stagnant
water and hence enormously attrac-
had held almost complete possession
of the district, rendering 1t uninhab-
liable to humans. They were so bad
that even the cattle could scarcely
be confined within the fences of the
excellent pasture land Of the district.
But the bats in DR.. Campbell's bat
roost enjoyed themselves Immensely.
After they had developed In sufficient
numbers to cope with the mosquito
hordes these pests were practically
full and the cattle settled down to
quiet grazing In pastures. In short,
the experiment was such an unqualf-
fled success that the city of San An
tonic made the bat roost a permanent
feature of its public health work,
and other cities soon followed suit.
Bats Immune to Mosquito Bites
DR.. Campbelrs attention was direct
ed toward the bat as an anti-mosuui-
to agent because it is immune to the
poisonous bite Of the mosquito. Bats
never contract malaria. This immun-
ity, he believes, is due to the size of
its spleen, which is very large in
proportion to its body. He is con-
vinced that the spleen, the use Of
which has long been a mystery to the
medical fraternity, was developed in
the human body as defensive agency
against malaria. In support of this
theory, he points out that the spleen
contains hormone. a compound hos
tile to the malaria bacillus, which
enables the system to resist malaria.
Besides this valuable immunity, the
bats habits happily coincide with
those of the mosquito, which greatly
increases the strength of its op-
position. Like the mosquito, it rests
in the daytime and makes fits forays
for food at night, and it also hiber-
mates through the winter. so that 1t
Is capable of surviving in q cold cl-
mate.
One Of the interesting discoveries
DR.. Campbell has made concerning
bats Is their striking antipathy to
loud and penetrating noises, Jazz mu-
Gil fa oh hpr
rent to them. and they cannot en-
dure the sound Of a jazz record played
on q phonograph. This dislike is USE
full, for it can be relied upon to rid
the premises Of bats whenever IL be-
comes necessary to do so. When driv-
made. declares this expert, they never
return.
The bat is not the only natural ene-
my Of the mosquito to prove useful in
it's elimination. There is Gamblsia
aitinis. for instance. commonly known
introduced by the United States gov-
ernment In various sections with
great success. The state of Missis-
sippi, especially, is said to have OBJ
tanned remarkable results by the stock
ing. Of its ponds and surface water
with this species. Although q mild and
Insignificant little fish. less than an
inch long, Gambusia has such vo-
racious appetite for mosquitoes that
he has them under what the govern
ment terms "complete control"
In spite of all this valiant effort to
exterminate the mosquito, however, 1t
is by no means becoming extinct, like
many species Of harmless wild AMI
mails. On the contrary, 1t Is very much
in evidence and ready to multiply
lie health autorities relax their vigf-
lance