, 1884-09-06
THE MOSQUITO
Said to Be a Carrier of the contagica
of Yellow Fever,
And n Factor In h Production OF
OBSERVATION-DISCLOSURES Ex-
Periments of DR.. PfnIay,
OF



lSt. Louis Globs-D emocratl
IL seems, from the observations OF DIR. Fin.
lay, OF Havana. reported in tins Annals OF
the Royal Academy of Sciences OF that
city. that there ART good reasons for supposing
that the musquito Is tho carrier of the con-
tagiun or virus Of yellow fever. He says that
tbs female alone stings and sucks blood, tho
male being Il harmless sort Of body that lives
ON the Juice OF vegetables, thosaof a sweet
character principally. Tn female stings,
not because she likes blood particularly, but
because IL furnishes an amount Of nourish-
ment and heat that is necessary In order that
the egg, she j about to deposit In the water
may hecome matGtcd Those that have sat
isfied themselves with blood lay Eggs in II few
days, while those which have purp1sely bsen
kept 70 they could not reach "A supply OF this
rich food die without ever tepositing any.
Tho blood Of q ersnn with fever is especially
In favor with lii, Insect. as it Is several dc
grees higher ia Temperature than that Of Il
healthy person or animal The larger variety
Of musquito Is able To take enough blood at
une time 10 enable II T. 90 vi with It's egg
laying duty. but tho smaller Oaei are more
vicious and have 10 come back Tor more
blood several times, avon ten or Twelve In
humber.
The singing APPARATUS l. composed OF sew
eral pieces, all coming 10 "a point, surround.
ing OF inclosing tho suction part OF the instru.
mcnt. The entire sting Is thrust through the
skin, when the outer parts are thrust aside,
allowing free entrance from the suction part
OF n drop Of acid, irritating material. This
virus Il injected for the purpose OF rendering
the blood more fluid and consequently more
capable Of being sucked into the stomach Of
the musquito. A part Of this H.. Of course,
rapidly diffuscd into the surrounding parts
and remains there as a gentle reminder Of the
visit. More Of IL remains IL the insect Is dis
turbed at its meal than II 81 Is permitted 10
get its fill.
Microscopical examination of the singing
apparatus shows that some Of the blood dries,
on the outside and another portion ndheres &c
the inside. ready 10 he washed into the next
puncture II makes along with the acid venom
or SILVA 1t injects. IL is easily seen how
the incubation OF a healthy person with
disease germs swarming IN the blood Of a
fever patient might occur, especially IL the
healthy man should be stung soon after the
musquito had been interrupted in Its meal Of
the blood Of Il fever patient.
DR.. Finlay has conducted experiments
which appear to support his theory in II most
convincing manner. He took Imprisoned
mosquitoes 10 the Yellow Fever hospital at
Havana, and caused them 10 sting patients
suffering with the disease. He then caused
people who were u~nacclimnted TO b1 stung
10y these Sanle insects In the frat case-
that Of II healthy person stung by the mus
quito two days aftor It had gorged itself
with blood from a patient in the fifth day Of
the disease-tho person Experimental upon
begun 10 feel unwell on the ninth day, and
had a well-narked attack Of yellow fever,
with iaundics and aibuminurin, which per
s-ied from the third 10 the ninth day OF his
Illness. In three other cases, in which the OK
f+'riments were conducted In the same man
uer, the results wore tho same, except that
he attacks OF fever were still less grave than
IN NhR AWaf IAn enrH LH a.. NU.H.a.NaH ..aaA.na
mated persons, from among whom these four
were selected, showed no symptoms whatever
OF yellow fever during the seven weeks they
were under his care and observation.
II should be noted that the subjects OF thess
experiments were ,tung but once by an in
footed musquito, and that the attacks O
fever were, in each case. remarkably mild
ones. 1t may be that by following this
method a mcans Of protective incubation
has been discovered, as 1t Is known that one
attack, however mild it may be, protects
against future attacks OF yellow fever.
DIR. Finlay calls attention 10 ths fact that
musquitoes are unable TO reach Elevated To-
c~alities because u the weakness OF their
wings, and when thoy are gorged with blood
they are still less able To fly and, besicol,
have no inclination to make any extra
amount Of e~xertion. Also, that they hibor-
nate, 90 10 sleep through the cold weather in
northern latitudes and are not killed. by frost.
IL Is in this way that the species is continued
FROM one season to the next. BayRrd Taylor
states that they are as mpacious on Lake
Ladoga, Russia, nearly within the Arctic
circle, as in India These facts 20 far to OK
plain the occurrence OF yellow fever on board
Of ships that have wintered at the north
after having the disease on board, as soon as
she reaches a warm climate, also that els-
vRted points In the fever region ara exempt
from Its manifestations The celebrated
case Of the United States steamship ply
mouth, - which wintored near Boston and had
two cases of the fever on board as soon as 1t
reached the Bernudas before 10 had revisited
an infected port, is TO be explained on the
theory that she had some fever-laden mus
Ceiitoes on board which had not been injured
by the freezing Of a New England winter
But these musical tormentoTs Of sleepy hui
manity are not alone the strongly suspected
carriers Of Yellow Jack" from the sick to
the well, but DIR, Patrick Manson, Of Annoy,
China, has detected them conveying affection
from man 20 man. 1t should be said, rather,
that II acts as a necessary go-between, than a
direct carrier. The affection Is known under
two different and, seemingly, totally dissimi-
lar forms. In the one IL appears as an enor-
nous overgrowth OF the skin and its underly
ing issues-elephantiasis, or elephant leg;'i
although the same structures In other parts
OF the body may become affected in the same
way.
The second form shows itself by the APP
pcarauce Of innumerable millions OF minute,
thfead-liko worms in the blood-the flarim
sanluinis hominis. They are about one
nineticth Of an inch in length and one thirty
five hundredth inch in thickness. Fifty OF
them could swim comfortably. side by side,
through an ordinary pin hole and never In
terfere with each others movements. They
are about the size of a red blood globule, and
can 90 the round Of the circulation without
clogging any Of the vessels, even the small
est. Their movements are extremely active
and snake-lke, and as many as 100 may be
counted in IA single drop OF blood. They arr
. be seen in myriads during the night, but
they diminish toward morning, aud by S on
y O'Clock they entirely disappear. What be-
comes Of them through the day Is unknown.
These are the embryos or incompletely devel-
opSd worms which. wheo mature, and under
certain circumstances vet to be mentioned.
produce elephantiasis.
The immature worms never go on TO full
development in the blood where they ara
found In such countless hunters. la order
u complete tn cycle OF its growth il must
pas into tie tody Of another animal. Ac-
cording 10 Or. Manson, the musquito Is the
intermediate host. When the female sucka
the blood of "A Ieisnu bearing myriads Of the
hlaria in The circulation, these embryo
worms arr taken into the Insects stomach,
where they have been found ia n larger pro
portion than in the blood Of the person from
whom they have been obtained. This proves
that the digestive juices OF the insect do not
kill the hlaria. Here it goes through IA sec
ond period Of development. which takes up
from four to Nx days BY this time tho
musquito dies and falls into the water; the
worm, which has acquired n boring Rppa-
ratus, leaves the dead insect and is prepared
for further migrations should 1t happen to be
taken into the human stomach along with
drinking water. After reaching the stomach
IL borcs IT. way TO the point which suits il,
which is in the Emphatic system. Herr II
attains full majority, and the disease ele
phantiasis Is established