Evening star., 1941-04-10
Of Stors, Men
And Atoms
Notebook of Science Progress
In Laboratory. Field
And Study
Bu Thomas r. Henry.

By Thomas r. Henry.
Discovery of the source of the dreaded
Jungle yellow fever of Northern South
America has just been announced by
Rockefeller Foundation scientists.
1t consists of two hitherto unsuSpected
mosquitoes which infect monkeys, opos-
sums, ant-eaters, sloths, armadillos, and
those giant rats, the agoutis, pacas and
capabaras. None of these animals even
is made i'll, so far as the Investigators
could determine, by the malady which
is so highly fatal to man.
This new form of yellow fever was
first described about 10 years ago. Hunt
ers and pioneers who went into the
iungles mysteriously sickened and died
1t has been known ever since the ex-
periments of Maj Walter Reed in Cuba
lust after the Spanish War that yellow
fever was spread by variety OF mos
quito, the Aedes aegyptae, which hVeo
only around human habitatons, and
science was we'll on the way to eliminate
the disease from the world by clearing
I'D the breeding places of these insects.
There were none of them in the Jungles.
The new outbreak was of special i'm
portance to the United States because
OF rapid air transportation between the
two continents, and tests by the United
States Public Health Service, which
showed that the population of a large
part of the South was susceptible to
the dreaded yellow jack.
Last year the Rockefeller Foundation
set up a laboratory in Colombia to solve
the mystery.
The first step was to collect every
known form of insect life from the
jungle Each species then was ground
up and systematic search made for
the yellow fever virus.
Only two obscure varieties of mosquitoes
were found to harbor it. The Rocke-
feller scientists then proceeded to trap
more than 1000 animals, representing,
so far as possible, every variety known
in the jungle. Blood tests were made
on each of these and the virus demon
strated in surprising number.
The jungle mosquitoes, they found,
bite these animals as well as man.
They have a strong resistance against
the infection. The yellow jack virus
lives only about four days in their blood.
But so long as it is there it is transmitted
readily to any other mosquito which
bites the infected animal and the in
sect continues to carry it for the rest
of It's natural life, which may be four
months. During this time it gives the
virus to every new animal it bites,
Once bitten an animal develops
strong immunity with the building up
of antibodies in its blood. These can be
detected by tests developed by the Rookie
feller Foundation workers and enables
them to tell what areas have been in
fected.
The population in infected regions can
be protected by vaccination. In the
past. however it has been necessary for
an outbreak actually to occur and prob
ably kill several persons before it vas
known where protection was needed.
Now the wild creatures, trapped sys-
tematically, will serve warning.
There is constant danger that yellow
fever may break through the barriers
of quarantine. The Rockefeller Founda-
ton scientists say, and might develop
into a cataclysm in East Africa, in India.
and even in the Orient to say nothing
of parts of the Americas"
The biggest scare of the year, the
foundation reports, came with an eX
tremely virulent outbreak in the Nubian
mountains on the Anglo-Egyptian from
tier. At first it was feared that this
| was in some way connected with the
movement of troops, but the latest re-
ports are that it was entirely confined
to the native population.
To guard against another development
| of this kind in the African war zone,
250,000 doses of yellow fever vaccine
have been prepared for the British gov
ernment. Vaccine also is being prepared
for the United States Army to use in
case Of an emergency, or for troops in
service in yellow jack countries. 1t is
expected more than million doses will
be in readiness.
The heads of Americans are getting
broader.
They are following the trend of the
more civilized" races of the world, but
perhaps at somewhat accelerated rate.
Such are the conclusions of DR.. Ales
Hrdlicka, curator of physical anthro-
pology of the Smithsonian Institution.
1t is a natural phenomenon. he points
out, with the increasing use of softer
and more concentrated foods. The
chewing muscles are less used, especially
in childhood. Consequently. from lack
of exercise, these muscles, the main one
of which covers the sides of the skull
are less developed. They do not exert
SO much pressure from the sides against
the skull.
The skull is expanding with the de-
veloping brain. 1t follows the lines of
least resistance. With the pressure of
strongly developed muscles in its way on
both sides. the development would be
more 10 the front and back, resulting
in long g-headedness. With this pressure