The Savannah morning news., 1900-07-20
HOW MOSQUITOES WORK.
SOMETHING THAT 1T Is WELL TO
KNOW AT THIS SEASON.
Taste for Blood Acquired-Method
by Which Insects Poison Is In
jected Into Human Beings-Have
Eyes in Abundance.

From the Baltimore Sun.
Scientists have for years been studying |
the disease germs taken by mosquitoes |
from one human being, developed in the
body of the insect and then into another
person to poison his blood with malaria,
but few have given much attention to the
study of the poison generated by the mos
quito itself and injected into the victim /
of his. or rather her, bite. The effects of
the poison are apparent every day in the
blotches, and sometimes slight alterations |
which surround the scene of the mosQui-
to's Understanding visit.
DR.. W 8. Thayer, who at Johns Hopkins
Hospital is engaged in a series of expert
ments which carry out the now accepted
theory that mosquitoes transmit malaria,
said yesterday that he knew of no scien-
tific investigation Of the mosquito poison
which accompanies every bite inflicted by
the insect So widespread are the raw
ages of the mosquito that nearly every |
one is acquainted by personal contact |
with the contents of the poison gland of
the little insect With the bite comes a
singing sensation of greater or less inten- |
sity. according to the susceptibility Of the |
person suffering 1t. Itching follows. which |
is usually alayed by scratching the bite |
Here Is where the damage is done, accord |
ing to some physicians. From the |
scratching finger neil germs get into the |
slight wound and these set up an irrita- |
ton and local Inflammation which may
result in the formation of a little pustule.
Finger Nail Does the Work.
1t is believed that the actual poison of
Il.
only a slight irritating organic poison
which would have no bad effects upon
the human system. it's irritating influence
soon wearing away. But the finger nail |
does the work by introducing germs into
the tiny wound. So minute are the little
poison CLAN and so small Is the amount
of poison secreted by the insect that no
one has taken the trouble to gather 1t in
quantity sufficient for chemical analy-
sis.
The function of the mosquitoes poison
is probably two-fold. Some observers
think it is injected to aid in lubricatins
the proboscis as 1t is inserted in the skin
to secure the insects meal of blood. An
other theory is that the poisonous saliva
serves to make more fluid the blood so
that it may be more readily sucked out
by the mosquito. This seems to be borne
out by the noted absence of irritation
from the poison if the mosquito is allowed
to suck his fill, as then the poison is
probably sucked out also. If the mosquito
is interrupted in his meal the full effects
of the poison are felt
DIR. Fulton Does Not Mind Them.
Dr. John S. Fulton, secretary of the
State Board of Health. SAYS that when
living in a mosquto-infected section of
Maryland he tried not to mind the little
pests, allowing them to have their feasts
off his blood undisturbed. Soon, he says |
he became immune to the poison, and no
longer minded the bites, nor was he in
convenienced by the punctures of the
mosquitoes.
They Do Not Have to Suck Blood.
While Baltimoreens are rising in their
wrath these warm evenings and nights
to smite the pestiferious mosquitoes that
are annoying them in their homes and
yards, they may be interested to know
just what they are shifting or would like
to smlte. In the first place. 1t is the fe-
male of the species that has the blood |
thirsty propensity.
The taste for blood is supposed to be |
largely acquired for it would obviously |
be impossible for all mosquitoes to feed |
on rm-blooded animals. Their regular |
diet is q vegetable one-juices sucked from |
fruits and flowers. Some species have |
been studied which still keep up their |
vegetable habits. OF other species the fe- |
males alone are blood-suckers, while the |
males stick to their vegetable diet. In
rare cases species have been found in
which both sexes prey on the blood of ami |
mails.
! How a Mosquito Bites.
The act OF biting of a mosquito has been |
likened to the sinking of an artesian well |
shaft. Its biting apparatus is the pro-
boscis, which has beep discussed into |
nine parts. One of it's principal parts is
the upper lip, which extends nearly to
the end of the organ, Beneath 1t and in |
a groove is long pointed canula which is |
a sort Of extension of the pharangeal tube |
Through this the blood is sucked. On |
either side are two lancet-shaped pieces, |
mandibles and maxillae, which prepare |
the way for the insertion of the pro-
boscis. The maxillae are more delicate |
and provided at the ends with a number |
Of spike-like berbs, probably to enable |
the mosquito to hold on after 1t has once |
started on Its quest for blood. Beneath all
is a shea IN which incloses the other parts |
except along its upper border when open. |
This is the lower lip. and is somewhat di- |
lated at IT'S end into pair of jointed |
valves These probably have to do with |
the sucking of blood.
When the proboscis is in action it is all |
forced into the skin except the sheath, |
WHICH 10 DeHl IiltO al cOIN vi iOOP, WUitn
becomes narrower as the piercing organ |
penetrates more deeply. Al either side |
of the base of the proboscis is pair of
jointed appendages. maxillary palpi The |
poison Is secreted either in two glands |
which are situated at each side of the |
thorax or in a single gland at the base |
of the proboscE
Their Seeing Apparatus.
The sides and front OF the head OF the |
mosquito are occupied by facetted eyes |
This probably accounts for the ease with |
which mosquitoes escape from impending |
smashing under an uplifted hand. They |
are able to see all around them, and so
are able to get out of danger In some !
species the eyes touch each other in front |
go completely do they cover the head.
over 24O Species.
A recent work on gnats or mosquitoes, |
by Mai George VI. Giles, an English In |
vestigator, names over 240 different spe-
cies OF these the culex varieties COM
prise about ree-fourths. These are dis |
tinKuished from the anopheles. or mals-
ria bearing mosquitoes. With the ex- |
ception of the polar regions 1t IL said that /
not at all extensive land surface on the |
globe is free from mosquitoes. In North |
America there are no less than forty-one |
culex species.
As rule the oulex is soberly colored, |
although under the lens he shows eab-