The San Francisco call., 1905-08-24

/ Sir Patrick Manson, who has just de-
livered a course of Lane medical lee
J lures in this city, has taken a great
/ deal of interest in the problem of pro-
( tecting San Francisco and Asia
from the introduction of tropical
diseases that may come from
the various countries that are in
close commercial relation to 1t. Sir Pat
rick is q director of the School of Tropi-
cal Medicine In London and is adviser
of the British Government on all ques-
tions relating to the sanitary condition
of the colonies Furthermore, he is the
discoyerer of the fact that a certain class
of mosquito carries disease and helps to
spread epidemics. He, therefore, speaks
with the highest authority in urging the
necessity of making here a close study
of tropical diseases. He fears the dan
ger of yellow fever being carried to
Asia when the Panama canal is COM
pleted is very great
In discussing the question for The Call,
he said:
One OF the most important factors in the
diffusion OF disease IS the intercommunication
of peoples. whether this be by trade, by travel
by pigrimages, by wars or otherwise. So long
as a community remains Isolated and cut on
from the rest of the world, SO long is ii spared
many Of the diseases of the rest OF mankind,
Once a community begins 10 rise in impor-
tance or be united in any way with the rest
trouble begins. There are various kinds Of
isolation. Geographical isolation. as by a
broad sea lofty mountain range. for ex-
ample. In primitive times there was nothing
more effectiveS but when men began TO navi-
gate the seas, and to make roads over or
through the hills. the protection afforded by
these natural barriers was broken down. and
diseases hitherto localized became difused and
almost general Thus cholera and smallpox
and doubtless many other deadly diseases of
the old world carried 10 the new and
70 less extent the diseases Of the new world
were carried TO the old.
AS TO YELLOW FEVER.
One sometimes wonders, in thinking of the
great American disease, yellow fever, why
there has not been a similar reciprocity; why
this disease has not managed to get itself es-
tablshed in the Eastern Hemisphere. That II
is capable Of successful expectation has been
proved over and over again by epidemics
great and small, which from time to time
have broken out in Europe, more especially in
Spain and Italy Nevertheless. yellow fever
has not succeeded in establishing itself per-
nanently in that part of the world. Why?
Reed and his colleagues have supplied, par
TALLY al least the explanation. The stego-
myia mosquito is not a perennial feature In
these countries. Apparently the chances of an
infected stegomyia. bridging the winter season
and then successfully inoculating the germ,
are small that the disease is killed out for
good during the first winter Yellow fever has
managed TO establish itself in West Africa
where the conditions are more favorable for
its special kind Of mosquito.
But, you may. say, although yellow fever
has been failure in Europe, why has Ii not
succeeded IN tropical ASIA ana its great con-
tnent and islands, countries with teeming pop
ulatons, stsgomyia in abundance dor this
mosquito is one Of the most widely diffused
and hardest of the tropical species). and,
moreoyer with q climate in many places al
most identical with that Of the fayorite haunts
OF yellow fever in America? Why, then. has
yellow fever never appeared there? Why has
il never shown Itself IN the Philippines, for
example. or in South China. or in the Eastern
Peninsula, in the great Malay Archipelago, or
in India, or in East Africa? The answer is
an interesting one particularly % at the pres
ent juncture. for 1 believe this happy state of
immunity is about 10 pass away, or, rather, is
in Imminent danger OF passing away.
LIKELY TO SPREAD.
Hitherto there has been little or no active
direct or rapid Communication between the
home Of yellow fever tropical America) and
Asia Such trade as there has been has fol-
lowed a circuitoue route and any yellow fever