The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-08-20
MOSQUITOES AND MALARIA.
LEARNED PROFESSORS STUDTIN9
THEIR RELATION.

THEIR RELATION
RosenroNes Show that the Insects Have
Monopoly of the. seed-Ench Variety OF
Mosquito PeddlSs It's Own Kind of
shnkeS-Johns Hopkins Hospital
From ns Baltimore saw.
To prove that mosquitoes convey malaria
is the delicate and painstaking task which
a number of investigators have set them
selves In the Johns Hopkins Hospital labo-
ratories. The scientific investigator avoids
experimentation upon human beings for va
rious reasons. One of these reasons, as
expressed by a doctor, is that such expert
ments are avoided, just as the practice OF
cooking with dynamite. for fear OF i'm
perfect control Of the heat and energy.
However, 1t has been found that birds
Chilli without emotion and are subject to
a type OF malarial fever closely resembling
that in human beings, except that the germ
is slightly different Consequently birds
are used as the objects OF the mosquitoes
incubation with germs Of Shakes
A Frenchman In Algiers discovered the
germ Of malaria in the sos. To this chill
producing miscroscopic object was given
the name Of plasmodium malaria. subse-
quent study has been along the lines OF the
life history and characteristics OF the germ.
Manson and Ross. English investigators
In India, and Grassi. an italian. advanced
the theory of incubation Of the disease by
insects, usually mosquitoes, as being the
most abundant and widely spread pest. 1t
is the work OF these experimenters which
Is being followed up and confirmed in Bal
hu nr1 oh
Eugene l.. opie, at the Johns Hopkins Hos
pital
First catch your mosquito" is the pre-
cept of these Investigators. This Is ac-
complished by the doctors themselves.
Armed with lot OF small glass test tubes
and raw cotton for shoppers, they 30 down
to the marshes OF some river. Their only
bait is human hide, each one exposing
portion OF his body which Is easiest to see
and reach with his right hand. When a
mosquito gets his bill we'll settled into this
tempting bait. a test tube is clapped over
It and the surprised insect springs to the
top Of it's crystal cage. The sportsman
quickly places a bit of raw cotton in the
open end Of the tube, which holds the mos
quito In It's prison. Then the hunter is
ready for another insect victim. Hundreds
of the insects must be caught for a single
experiment.
The other live part OF the experimenters'
outfit is a number Of crows, which In this
region have been found the most suitable
birds for experimental purposes.
The mosquitoes will survive for several
days in their glass cages. but the doctors
do not tarry long before beginning their
experiments. In the first place the mos
quitoes must be inoculated with the ma
Iarial germs. These are supplied from the
laboratory stock. for the mosquitoes are
not generally furnished with the germs
when caught. BY feeding the germs are
introduced into each mosquitoes stomach.
Then commences the delicate part Of the
experiment.
Every two hours. or whereabouts. a mos
quito must be killed and its body prepared
for microscopic examination. This search
the malarial germs are broken up in the
mosquitoes stomach. Each part becomes
impregnated in a little sac or tumor in the
stomach wall. Within this sac minute
formed. and finally the sac bursts without
the stomach, thus allowing the little bodies.
which have the power OF movement. to get
into the circulation OF the mosquito. Once
In this condition they quickly find their
way to the salivary glands OF the mosquito,
where they congregate. BY this time the
mosquito 10 ready for business" and those
Of the insects which have not already given
up their lives to the inquisitive eye Of science
may be used to ipoculate the malarial germ
Into birds or animals.
During this intermediate process in the
body OF the mosquito, the doctors have
learned that the malaria germ is one Of
three varieties. producing one Of three dis
tinct types Of the disease. One form OF
germ, which splits up into from eighteen to
thirty Of the diamond shaped bodies ma
lures every forty eight hours and causes the
every other day chill or tertian variety,
when introduced into the human circulation.
Another form. splitting into fewer bodies,
produces the chill one day and respite for
two, or the quartan variety Of malaria. A
third form develops irreguarly and produces
corresponding irregularity in the time Of
chills recurring.
is bred by distinct variety of mosquito.
The tertian. or every other-day chill, germ
is found only in the mosquito known as the
anopheles claviger. or key bearer"
With his mosquitoes thus loaded" as It
were, with germs, the doctor is ready to
begin his incubation of the crows When
the mosquito uses it's proboscis to suck the
blood OF Its victim, 1t injects from It's sail
vary glands portion Of the fluid which Is
impresnated with malarial germs, OF
blood vessels, travelling from small capil-
laries to veins and arteries. The nrsy OBJ
1ect Of attack OF the little diamond shaped
bodies. bred In the mosquito, Is the red
blood corpuscles. Some CT the tiny bodies
force their way into the corpuscles, al
though. Of course. many OF the corpusclee
successfully resist the attack. Many OF the
little bodies perish In the struggle for ex-
istence."
Those OF the little bodies which secure
resting place within the corpuscles quickly
go about their subdivision method Of propa-
CATION, and at the given time the increased
number OF diamond shaped bodies are ready
to burst forth from the corpuscle. This, oc-
curing at stated intervals. according TO the
time OF maturing Of the particular variety
of germ, causes a chill. as the thousands
of infected corpuscles burst at nearly the
Same minute. In this way a microscopic ex-
animation OF the blood of an infected per-