Evening star., 1933-12-17
RESEARCH REVEALS.
'Sk|N COVERS BRAIN
Carnegie Institution Labora-
/. tory Reports Experiments
on "Dura Mater"
The brain has Q rubber skin"

11lC Gill 41do 4ubOSL ohA1'
Discovery of what may be an i'm
portant factor in the mechanics Of the
central nervous system has just been
announced by the embryological labora-
tory of the Carnegie Institution of
Washington.
Brain and spinal cord are covered
with tough, fibrous membrane known
to neurologists as the "dura mater"
Inside this Skin" is the brain, sur
rounded by liquid of about the same
chemical composition as blood, except
+ that it has no red cells.
In experiments with dogs and cats,
Drs. L. B. Flemer J. H Clark and
: l. H. Weed of the Carnegie staff found
snat when the animals position was
changed from horizontal to vertical
the change which man and the apes
lad to undergo in evolving from four
legged to two-legged animals-this dura
mater shows definite stretching which
permits the shifting of the cerebro-
spinal fluid from one region to another
of the brain cavity without change of
volume.
Shows Effect of Age.
1IlNeSllBdJIOu SllOWcQ IlldS
the brain skin will go back to its orig
/ inal shape again when the position is
reversed-in other words, that 1t Is
/ elastic and obeys the physical laws OF
an elastic system. They calculated the
"co-efficient of elasticity for the dura,
when they came upon the surprising
! fact that it grew less the older the
subject.
Thus the discovery shows a hitherto
unsupported effect of growing old,
which may have important associations
with other phenomena Of SeneScence.
When an animal race passed from
the horizontal to the erect posture, the
position of the brain was altered radl-
cally. The investigators suspected TINS
must have been accomplished by de-
yelopment of new mechanismS for pro-
lection of the central nervous system
against the liquid preSSureS OF the
cerebro-spinal fluid. This. apparently,
did not happen. They found exactly
the same co-efhc;ency OF elasticlty IN
the macaque monkey. which hab1tually
stands erect, as n the dog, which ha-
bitually goes on four legs. The same
is considered doubtless true for men.
Probe Rate Of Flow.
DR.. F1exner and DR.. H. Winters
pushed still further their investigations
of the hydraulic system OF the brain
to determine the rate of flow, and prob
able rate of formation of the cerebrO-
spinal fluid itself. This is filtered out
of the blood by mechanism within the
brain and flows through an opening
known as the aqueduct of Sylvius. When
this is plugged up the condition known
as hydro-cephaly, or water on the brain,
develops.
They placed a special flow gauge at
the outlet of this aqueduct of Sylvius
in an enesthetized cat and found that
it was subject to wide variations. There
might be a constant flow for several
hours or an active flow alternating with
periods of rest. Some of these were
not associated with charges in blood
pressure.
Other discoveries during the year, re-
ported in the yearbook of the inStitu-
ton prepared for the annual meeting
of the trustees, tend to throw doubt on
some Of the accepted principles Of neu-
rology. One Of the experiments resulted
in earthWorms that would not burrow
and crawl with their heads up DR.
H. G. Schwartz cut away parts of the
cerebral ganglia Of earthworm-the
foremost mass Of nerve cells in the
worms body which is the basis of the
brain in higher forms of life. He found
that the ganglia tended to regenerate,
butt that connective tissue cells changed
into nerve cells. Hitherto it has been
assumed that nerve tissue could arise
only from nerve tissue. The ganglia
appeared to be completely regenerated-
but the worms could no longer be per-
suaded to follow their ancestral custom
of burrowing. They crawled with the
front parts Of their bodies held up.
Cataract Found Hereditary.
Investigations by members of the
staff of the embryology department, 1t
was reported, have placed another fairly
common heart ailment, eye cataract,
in the class of hereditary diseases.
Study of family showed this defect to
be passed on as a dominant, appearing
in about so per cent of the members
in direct line Of descent. It was de-
termined, however, that the hereditary
factor responsible for the disease re-
quired just the right conditions in
which to show itself. Hence some who
have inherited cataract never actually
have 1t.
Still other experiments demonstrated
that the chromosomes, the microscopic
particles in the cell which carry its
hereditary characters and which are
bundles of still smaller particles. ap-
parently have an independent move
rnent of their own. They act as If they
we're actual living entities instead of
purely the servants of mechanical
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