Evening star., 1940-07-30
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
By Thomas r. Henri.

1neSe DrOadcaStS are the cause OF
some of the static on earth, especially
when the great conelomeration of stars
is directly overhead.
The source of this static has just been
traced by Drs. Louis G. Henyey and
Philip c. Kennan, University of Chicago
astronomers.
The Milky Way is the mass light effect
of all the stars between the earth and
the edge of the so, 900 900 ,0OO-star galaxy
OF which 1t forms part, looking in
the direction of the center. 1t is almost
empty space in which stars are dis
tributed many quadrillions Of miles apart.
Every time free election travelling
along a straight line in this interstar
space is detected from its course by a
stripped nucleus of a hydrogen ion the
astronomers explain. minute wave OF
radio energy is created. Hydrogen ions
in space are rare, even from an astro-
nomical point of view with only one to
each cubic centimeter. But the cumu-
lative effect of all the impacts and de-
f1ections in thousands of light years of
distance add up to enough to effect
sensitive receiver.
Reinforced jaws for heavy chewers
are among natures inventions.
DR.. Ales Hrdlicka, Smithsonian Insti-
tuition anthropologist. reports finding
curious bone formations, probably in
tended to strengthen the jaws for ex-
cessive mastication. in a study of nearly
5000 lower jaws from skulls collected
all over the world.
He calls them "mandibular hyperos-
toses"
DR.. Hrdlicka describes them as "vari-
Gus grades and forms Of supplementary
hard, bony tissue on the lingual surface
OF the body of the mandible. They
occur as rows of tubercles or low, more
or less vertical ridges, separated by
grooves, as low conical bulges in the
pre-molar region, or in a more or less
knobbed and tumor-like condition
The bone in all cases, he points out.
is hard and compact. None of these
formations ever causes any inflammation
and never ulcerates nor decays They
behave wholly, DR.. Hrdlicka says, as
normal bone. Sometimes, however, they
cause great difficulty in fitting dental
plates and there are instances where they
have fused on both sides to form
pair of shelves" almost joining in the
front of the mouth.
There has been some speculation he
explains, that these growths might be
throwbacks to primitive condition of
man or his apelike ancestors. They
are found neither among the great
apes nor such early pre-human types
as Neanderthal man, however. They
may appear at any time during adult life
and are slightly more frequent and
prominent in men than in women. In
few cases they have been found in
children which, in the light of Dr..
Hrdlicka's hypothesis as to their cause,
is quite significant.
While traces of them are found among
nearly all races they are far more fire.
quent in the north and the south and
reach their greatest frequency among the
Eskimos. 1t is notable that they are
more common in the jaws of the early
Morse settlers in Greenland than in
Scandinavia. These colonists approached
quite closely the frequency recorded for
the Eskimo.
This leads to the conclusion that the
formations must be due to some environ
mental influence. Actually it can be
explained very WE'LL DR.. Hrdlicka said. as
natural response of jaws used exces-
sively for chewing, such as is necessary
for the children of the Arctic with their
diets made up almost exclusively of
tough meat
ut is we'll known to every anatomist," :"
he says, that where there is a material
or prolonged heightening of muscular ac-
ton the bones to which the muscles
concerned are attached respond oy
thickening OF the bone and frequently
its enlargement. 1t is an unquestionable
fact that the demands on the jaws in
the Arctic and sub-Arctic regions is in
the main much greater than that else
where. 1t could therefore be expected
that the jaws of these people would re-
spond to this demand by STRENGTHENING.
AS matter of fact these northern jaws
Eskimo, Aleut or pre-Aleut-are among
the strongest and heaviest of modern
jaws. Even so, however, many of the
mandibles evidently prove not strong
enough for the demands, and bone reacts
to the demands by such strengthening
as it is capable of-and this seems to
include hyperostoses. 1t appears i'm
possible to explain the overgrowths in
any other way"
But according to this hypothesis the
bony growths should not occur except
after years of stress on the chewing
muscles. They are rarely found in small
children who probably have never had
to masticate tough food. This gives some
ground for belief, DR.. Hrdlicka says,
that supposedly purely functional
physical phenomenon may in some way
have gotten foothold in the heredity of
some strains of Eskimo. Nobody knows
how such functional anomaly is thus
perpetuated. At the best there is bare
hereditary trace of it.
The phenomenon was first observed,
DR.. Hrdlicka points out, about so years
ago and has been noted occasionally by
physical anthropologists ever since, but
his own is the first systematic study ever
made of it. If the anomaly actually has
gotten some hereditary foothold in some
races it is too late for it to play any part