The times., 1899-08-27
hALARIAAND MOSQUITOES
The Insects Are Charged With
Transmitting Germs.
BacterioIogists Are BENDING Their
ing the Cause of n Disease Thut
Aiiicts Humanity i'm Low and
Marshy Places-Experiment Made.

| aiSh ny SCIENTISTS ana physicians
with the germ theory of disease is today
being prosecuted with great vigor.. Each
year develops some new line of enquiry
into bacteriology which bids fair to un-
fold secrets of of ihcalcalable Importance
TO the human race.
The latest line of ARCHAEOLOGICAL inyesti-
cation, which is being carried on in va
rIous parts of the world has been inau-
gurated with the view of discovering
something about the causes and the mode
of transmission Of malaria Although
this disease has affected men in different
parts of the world from the beginning o,
medical history very little is known abo 1T
it. 1t has been observed. however, that
it is more prevalent near low and swampy
| been determined
| The Insect Theory.
A theory which has gained much Gre
dence among medical men of late is that
mosquitoes are the media through which
the germs of the disease are transmitted.
! This theory is now being investigated in
this country and in Europe. Along with
the enquiry as to the part the mosquito
plays in transmitting malarial germs, the
germs themselves are being closely stud
led with a view of determining something
concerning their character and treatment
which may render them ineffective. The
mosquito theory has been discussed for
several Years but il has never been proved
that the insects carry the germs of the
| disease.
DR.. A. f. "A. King OF this city, formerly
dean of the medical faculty of Columbia
| University, was one OF the first to adj
vance this theory. 1t was quickly adopted
by other medical men and experiments
have been made at various times.
Frenchman in Algiers is said to have
| discovered the germ of malaria in the SOS.
To this chill-producing microscopic object
was given the name of plasmodium ma
lariae Subsequent study has been along
the lines of the life history and character
istics 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
ttimore by prs. John B. McCallum and Eu-
gene L. Opie. at the Johns Hopkins Hos
phal. -af
Investigators at Work.
First catch your mosquito is the pre-
cept of these investigators. This is ac-
complshed by the doctors themselves
Armed with a lot of small glass test tubes
and raw cotton for shoppers, they go down
TO the marshes of some river. Their only
bait is human hide, each one exposing a
portion of his body which is easiest to see
and reach with his right hand. When
mosquito gets his bill well settled into this
tempting bait test tube is clapped over
it and the surprised insect springs to the
top of its crystal cage The sportsman
quickly places bit of raw cotton in the
open end of the tube, which holds the mos
quito in its 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 mala-
rial germs. Those are supplied from the
laboratory stock, for the mosquitoes are
not generally furnished with the germs
Wien CduSAl- by lStdluE lue SciElS are
introduced into each mosquitoes stomach
Then commences the DELICATE part of the
experiment
Every two hours, or thereabouts, a mos
quito must be killed and its body prepared
for microscopic examination. This search
under the magnifying lenses discloses that
the malarial germs are broken up in the
mosquitoes stomach. = Each part becomes
impregnated in a little sac or tumor in the
ctoy oh Within this
bodies, lenticular or diamond-shape, are
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 is ready for business and those !
of the insects which have not already given |
up their lives to the inquisitive eye of SCI
eDce may be used to inoculate the malarial |
germ into birds or animals.
Types of the Disease.
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
natures every forty-eight hours and causes |
the every-other- day chill, or tertian va
riety, when introduced into the human cir
cuation. 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 irreg-
ularfty and produces corresponding ir
regularity in the time of chills recurring.
Strangely enough, each variety of germ
is bred by a distinct variety of mosquito
The tertian, or every otherday chill, germ
is found only in the mosquito known as the
enopheles 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 its proboscis to
suck the blood of its victim, it injects from
its salivary glands portion of the fluid
which is impregnated with malarial germs
OF course, the germs get directly into the
blood vessels travelling from small capil-
laries TO veins and arteries The first OBJ
lect of attack of the little diamond shaped
bodies bred in the mosquito, is the red
blood corpuscles. Some of the tiny bodies
force their ways into the corpuscles, al
though, of course, many of the corpus
cles successfully resist the attack Many
Of the little bodies perish in the struggle
for existence
Invasion of the CorpuscIes.
Those of the little bodies which secure
a resting place within the corpuscles
quickly go about their subdivision method
Of propagation, and at the given time the
number OF diamond shaped bod
es are ready to burst forth from the cor
ouscles. This, occurring at stated inter-
Fals, according to the time of maturing