The sun., 1909-02-21
DISEASE And THE MOSQUITO
SIR PiTRICK MANSON TELLS
or MS DISCOVERIES.
Methods by which scioice Has Demon
strated That MaiarsA. Yellow Fever
and Other Diseases Are spread by
Blood sucking Insects-WarninE.


Blood SUCKING Insects Warning
loNpDN. Feb. io.-Science never had
better exponent for the layman thar
Sr Patrick Manson. tho man to whom
above all others Ia due the credit Of dis
covering the secret Of the spread Of many
-:trascS through the medium OF mosaui-
"vcs and other insects. In q luminous
speech at a gathering in his honor the
other day he told the whole wonderful
story Of his Investigations in language
simple enough for the man In the street
10 understand. Sir Patrick's subject
was My Personal Experiences Of the
Mosquito" and he said:
In 1874 came To London, and there
for the first time heard that Timothy
Lewis had discovered that in the blood
Of proportion OF the inhabitants In GER
tain districts Of India there was to be
found an organism which he called the
Fiiaria sanguinis hominis. This IL a
microscopic animalcule. eel shaped and
enclosed in a loose sac or sheath, within
vhich it wriggles about in the blood very
actively. 1t Is sometimes present In
enormous numbers-hundreds in every
drop OF blood. These parasites Lewis
had found. in more than one instance,
phantoid diseases.
ION my return to China in 1870 endeav-
ored 10 ascertain il these parasites oc-
cured also in China. | discovered that
they were present in some districts in
u per cent. Of the population; in Other
districts in 50 per cent; while In some
places they we're not found at all.
Tine problem natul ally suggested it
81. How does this pai asite for such 1t
IS contrive to pass from one human being
- another? Now it occurred to me
that II it could not pass by virtue Of its
own onort from one human body TO
another some other agent must inter-
vtne and that that other agent must be
capable Of piercing the skin OF the
human body. and must absorb the blood
Of the human body and with the blood
the little wriggiing parasite which it
contains. Vow, the agent which occurred
to me as being the most likely TO erect
this necessary step in the translation Of
tie fiaria vas the mosquito.
ANIGHTLY wASDERRB.
/ found that the filaria was not always
resent in the blood near the surface Of
tho body. and further found that II had
'o,uliar habits as regards its appearance
aud disappearance there l found that
~ ordinary conditions OF health filarie
c,me into the blood just about sunset.
rradually increasing in numbers toward
',jdnight, and then gradually decreasing
% numbers toward morning. 1t looked
- if this. what | call fiarial periodicity,
vas an adaptation of the habits Of the
Elaria TO the nocturnal habits Of the
mosquito.
Thus encouraged. to test this mosquito
doctrine l persuaded q Chinanan for a
mall consideration to sleep below what
/ called a mosquito house that is to say,
n large framework covered with mosquito
netting big enough to accommodate
led. This was erected in roop in
which mosquitoes abounded.
The Chinaman went in there in the
evening and kept the door Of the mosquito
house open for half an hour. until plenty
{ mosquitoes had entered it, Then he
,losed the door md slept as comfortably
H~ he could until l.iorning. Next morning
] entered the house and found dozens
"r mosquitoes gorged with blood clinging
go the walls of the house. These trans
tered to small bottles and examined
ZEN serially at intervals Of a few hours
NJ few days endeavoring TO find out II
rne filaria was ingested with the blood
nich the mosquitoes had imbibed. and
Z ingested what changes might occur
~ the way Of development. OF perhaps
% the way of digestion.
EARLY LIFE OF THE PARASITES.
1 shall not easily forget the first mos
onto | dssected so charged. / tore of
b., abdomen and by rolling q penholder
from the free end OF the abdomen to the
.-gerel end succeeded in expressing the
it2nd the stomach contained. Placing
= + under the microscope ] was gratified
- ind that so far from killing the filario !
digestive juices Of the mosquito seemed
'' have stimulated it TO fresh activity;
Now j saw a curious thing. The |
ilA sack or bag enclosing the filaria
8 rich hitherto had muzzled II and pre-
'"H'"i il from penetrating the walls OF
no blood vessels in the human body was |
oxen through and discarded. The blood |
8 hen il enters the mosquitoes stomach |
20 ter which 1t contains becoming alb
."'pei. Ii acquires terlike consistency.
DHls now tarry fluid seems TO cling TO the
."ck in which the filaria lies.
The filaria seems to be conscious OF
',l, and vigorously butts at one end OF the
* until il succeeds in breaking its way
~oIgh When this is effected the Filaria
"rICges away in a definite direction. as II
l search Of something.
When | saw this for the first time be-
loved | had stumbled on an important
'gct with distinct bearing on human
'llhology. followed it up as best could
"tn the meagre appliances at my dis
al and after many months OF work.
following up false scents, ultimately
sInn ded in tracing the filaria through
.l' stomach wall into the abdominal
"tyity, and then into the thoracic muscles
z the mosquito.
Later. probably influenced by discov-
'rIcs IN connection with malaria. ] set to
work again-this time in England-with
'egter appliances, to see II | could trace
lore precisely the exact route by which
the little animal left the mosquito. i OBJ
llned infected insects from DR.. Ban
,r,ft Of Australia and l set Dr.. Low to
."ction' them at the London School OF
Tropical Medicine.
DIR Low succeeded In making beauti-
'nl sections which clearly demonstrated
hat the flaria, after il leaves the stomach
and reaches the thoracic musclcs Of the
Mosquito. continues after certain period
IN which il increases IN size, its journey
toward the probcscis; that for q time II
lies in the head Of the insect that then IL ,
CreepB down the labium or sheath Of the