Evening bulletin. [volume] (Honolulu [Oahu, Hawaii]) 1895-1912, 1901-09-05

,
surprise to find that a solution of bi.
cllUride of mercury sufficiently strong
to kill all micro-organisms, or germs,
ate ted the larvae slowly. some being
alive at the expiration of twenty-four
hours. In weaker solutions they lived
Indefinitely. 1t would be unsafe under
any condition to use this dangerous
agent in ponds. etc, which are fully
exposed: this may also be sa.d of car
bOlic acid and other agents expert.
mented with. Permanganate of potas
sium. which has been strongly recon-.
m, nded for the destruction of larvae,
produced but little effect. except in
very strong solutions, During these
te,ts the marked superiority of petro-
lenm oil soon became manifest.
There seemed to be no special ad.
vintage of one petroleum product over
arcther. The Lima oil which was used
in petrolizing the stagnant pools and
rain barrels. etc. Is n crude petroleum
with a minimum amount OF naptba,
One cubic centimetre of this added To
o,Dtn cubic CentlmetrGS of wafer cons
tanning larvae killed then in ,nree or
iour hours. This is eouiyalent IN about
twenty drops of oil in n gallon of wa
ter. As a matter of fact tins result
was usually obtained nv less than this
amount OF oil. Whether the destruc.
tive action of the oil on the larvae is
dine to some specific oua,itv or wbetber
II obstructs respiration I am NOT at
present able to saw However am in
clined to believe II 10 tho ,atier. fpr-
IN, rmore emapations from tho oil or
its odor. or both. are particu,orIy
rerugnant If not dangerous TO the fuIl
grown mosouito. There IL no doubt
that the hest effect of the oil Is gained
by introducing IL to n considerable
depth under the water. In this way Il
is more surely brought i'm direct con-
tact with the larvae. particularly IL
the water is agitated."
The small amount of petroleum re-
auired to spread death among the
colonies of larvae is inaeed one OF the
most satisfactory results. It is certain
that a solution OF twenty drops of
petroleum to a gallon of water will not
be destructive to the vegetation of our
own rice and taro fields which are I'M
auestionabiy the PRINCIPAL local breed
ing places of this nest. Every time the
MOSQUITO problem comes M tor dis
cussion the point is raised that in Or
der to be rid of the nest there must be
a sacrifice of this important agricul-
tural industry. These experiments of
Or Doty prove this idea to be a false
oae. Under the local system of irri.
cation it ought to be possible to mix
TIE petroleum with the water as 1t
passes from the artesian well pipes,
mus securing the iloodIpg OF all ne,ds
at one time. II such a scheme were nc.
con.panied by general SPRAYING OF the
grass and rusnos bordering ON tng
acids. the great centers of mosouito
breeding could be covered in a day.
WITH this pest as every other DR..
Uoty found It to be absolutely neces.
sary that operations for determination
must not be confined to a single pond
The work must be general to be eff
fective. Clearing one pond accom-
plishes little unless those adjoining are
deal. with.
At the conclusion of his report DIR
| Doty makes a statement that seems
entirely reasonable, and knocks into a
cCcked hat the local idea that mos.
quitoes can be destroyed by the propa
/