The Washington times., 1901-10-13
WAGING WAR ON MALARIA
Known Facts About Mosquitoes
as Carriers of Disease.
what the Scientists Hope to Accom-
pIish Toward Erndicating n Great
Evil A Novel Theory Advanced
Regarding Camps of Laborers.

| BOSTON, Sept 2S.-A paper of much
popular interest, soon to appear in the
Journal of the Massachusetts Associa-
ton of Boards of Health, upon the reIa-
ton of mosquitoes TO malaria, has been
prepared by DR.. Theobald Smith of Har-
ward University, who, under the direction
of the State Board of Health has given
considerable attention to the disease as it
has prevailed in Massachusetts during the
past six years. Through the kindness of
the officers of the association, it has been
made possible to present in advance some
1 of the more important passages of the
| paper. Though it aims only to present
a brief connected survey" of recent dis
| coveries regarding malaria and mosqui-
toes, it nevertheless brings out a num-
Der of points which will be entirely novel
to the general reader Coming at time,
/ too. when the seasons vigorous cam
paign against the mosquito Is closing.
with the advent of cooler weather Dr.
Smiths article may be taken as a re-
sumo of what has been done, and what
may be done, in the warfare against ma
| laria-especially what may be accom-
! plished by smaller communities and by
| individuals when mosquitoes and malaria
| come round again another year.
| DIR. Smith, it will be remembered. was
| the uiScONeTeT OF lit ulIItTtuCe between
the bovine and the human bacillus of tu-
berculosis, as has recently been pointed
out in connection with Dr. Koch's address
in London. In the matter of malaria too
whatever he may say in regard to the ma
ture and transmission of the disease has
more than usual interest from the fact
that the present knowledge of human ma
laria is largely based upon the investiga-
Of a a1ar ri Tul,f h.
took, with the assistance of F. L. Kill
borne, some ten years ago, and which re-
suited in the discovery that the tick
was the intermediate host" as it is
called, or general medium, as 1t may be
less technically termed, which carried
from diseased to healthy cattle the So
called Texas fever that has so often raw
aged the herds of the great Southwest.
The paper begins by pointing out that
malaria and the part of the mosquito in
spreading II have been studied by four
classes of men. The first step was the
study of the disease itself from the stand
point of the physician; the second the
study of the malarial parasite. to which
the medical biologist and the zoologist
have devoted themselves; the third the
study Of the mosquito, undertaken by the
zoologist and entomolOgist; and the
fourth, the investigation of the best way
to get rid of the mosquito, which is the
work of the entomologist and the sani-
tary engineer. The fact which is well es-
tablished, and on which the whole war
fare against the mosquito depends, that
the germ of malaria develops partly in the
red corpuscles of the blood, and partly in |
the stomach and the stomach walls of the |
mosquito, so that both mosquito and man !
are required to enable it. to complete its |
life cycle, was the discovery of many men, |
each working on knowledge supplied him |
by others. By one investigator or another |
it was found also, as DR. Smith points out /
in an interesting paragraph, that malarial |
parasites live in the red corpuscles of |
frogs, turtles, lizards, and snakes; that |
birds-crows, pigeons, finehes, and sp4r-
rows-in different parts Of the world are |
also affected with malaria; and that the
parasite occurs In mammals other than
man, as cattle, sheep. and dogs-in ali Of
which it produces severe and destructive
diseases.
Man, accordingly, was not the only one
affected with malaria, the same disease
was general in animal life. Nevertheless.
all efforts to prove that the parasites of |
were able to infect the human |
subject or that the human maiarial par
q failure. Only one thing carried the par
asites of human malaria, and that was
the mosquito. Moreover. although it was
found that the CuieX mCsuuito carried |
the malaria of birds only the Anopheles
mosquito could carry that of human
beings. Regarding the mosquito in gen
zral and the Anopheles t--squito in par
ticular, DR.. Smith says:
I'm consideration of the large number
1f species which occur III most localities
It is said that there are not less than 80
na.gaHaa slaaaN faHnH~ Nass.V 4.
entire world-it is, of course a problem
1f the greatest Importance to find out /
which species cause malaria and which |
10 not. In solving this problem perhaps
10 one has done more than a certain Ital-
an zoo!ogist. Grassi, who studied the |
of the mosquitoes in Italy. !
He found-and his >2rk has since that
line been conhrmed-that Of the twa |
great genera of mosquitoes that are
commonly found in various localities, |
culeX and Anopheles. Anopheles is the
'neethat carries malarial parasites
by making careful comparative studies
With Infected CuleX and by allowing pa
lents to be stung by Anopheles, he
cached the conclusion that the genus
Anopheles is the one which transmits hu-
nan malaria, and that Culex has nothing
o do with it. From this position Koch
Nssented several years ago, when he ]
studied he disease in Italy and he | :
# Culex transmit the disease. But | |
I'M not aware Of any further statement |
Il his upon the subject. and l think we
must rest cOntented with these state ! ,
nents for the present, since the Italian ! :
clentISts have made personal and very | {
horough Investigations into this subject"
with the life history of the mosquito | {
tudIed as 1t has been, the theory that
he mosquito Is the only agent in trans | |
hitting malaria is believed to be scien-
lhcdlly proved. The only difficulty has
'een TO explain the conditions under
which malaria appears Wien large pub
&c works are undertalSen-cana dug.
abroad cmbankmeuts built, or drinking ,
yater and sewerage introduced. Here
here Is Simply the ovcrturning Of the
oil, on which the epidemic of malaria
oHows. The old theory, says DR. Smith
hat the mdlarial organism lives in the l
oil for untold ages until 1t is turned up | s
s utterly ridiculous and cannot longer 4
e entertained, 50 that the question arises .
S TO how 1t is possible to account for
ldlarla appearing tnder such cirCum-
tances. For undolBbtedly- It nearly al
rays does appear. Dr Smith answers +
he question thus. b
There are seVerssl conditions that we | =
hou.d take into account In the first !!
lace, all such work Involves the tenn !
orary formation Of inequalities of the |
Iil. the interference with the natural | !
aeddins OF the water from the soil and o.
Ne consequent formation of puddleS In | q,
hlch mosquitoes may bred. Then in the | N
cpnOnllc conditions which prevail today | :
has been customary, in order 90 get -
FORK done. to import laborers in large +
GmncGS from different places to keen | al
hem near the work and this has given | -
se TO the formation Of Iaborers' camps +
'hese camps have generally been near a h
purc' OF water, because proximity to al
'atcr was "A necessity for camp life
Omctimes this water was running some !
m,s IT was Stagnaut. Then "A third C'
1nd,ton was the iHtrodUction Of individ- l.
dis who had probably been through a II
umber Of malarial tpido mics ia other =
d f~ys yg-fef fra ba.r "a |