Evening star., 1935-05-28

An animal doesn't "die altogether, Z"
it is shown py experiments conducted
at the Department of Animal Biology
of the Carnegie Institution of Wash
ington.
Some parts of an organism may be
alive three or four days after the crea-
ture is dead 1t all depends on the
vitality of different cells. Some kinds
have much more tenacity of life than
others. and there may even be differ
ences between cells of the same type.
The experiments. as described by
Dr. George L. Streeter. director of the
laboratory, were based on the differen-
tial staining effect on dead and living
cells OF a dye known as neutral red.
Every living creature may be consid-
cred as vast and extremely intricate
organization of billions of these cells
in an aggregation somewhat compar-
able to city or State.
IF alive" says DR.. Streeter, the
cells take up neutral red in their
granules and vacuoles. and the cypto-
plasm and nucleus remain unstained.
When dead the granules and vacuoles
DO not take up the dye. Instead, the
whole cell stains diffusely. there is a
change in the texture of the nucleus
and the nuclear membrane becomes
distinct. BY means Of these criteria 1t
was determined for wide variety Of
cells how long they remain alive after
the death Of the animal.
I'm these experiments the duration
of survival depended on how we'll each
type of cell, in its chemical and physi-
cal makeup, was fitted to live under
condition of death of the organism.
Large macrophages and kidney epi-
thelium in small fragments of tissue
kept in neutral solution at room tenn
perature lived as long as l20 hours.
Fat cells and intestinal epithelium
under the same conditions survived
only Is hours.
"In studying human aborted speci-
mems. where the embryo is commonly
retained several weeks after death, one
finds evidence of survival Of some cells
and tissues over others, thus altering
the astrological picture. For instance.
one finds surviving endothelial cells
leaving the walls of the vessels and
migrating into the degenerating blood
mass. Disparity in survivorship IS
still better seen in tissue cultures,
where some cells can be kept alive
almost indefinitely"
Dwarf Stars-much smaller than
the sun and far too faint to be seen
over great celestial differences-must
predominant in the heavens, accord
ing to a Carnegie Institution OF WASH
ington census of the bodies within is
light years, or approximately l00,-
OOO, ,000, ,000, 900 miles, of the sun.
There are 36 known stars within
this distance. Not one is giant"
Four are somewhat brighter than the
sun. Three are white dwarfs." a
type of star having high temperature,
small size and great density. The
% others are faint red dwarfs. One
of them has a luminosity only a
thirty -thousandth that of the sun. The
nearest giant is the great star Arc
turus. nearly 40 light years away.
The faintest stars, says DR.. Alfred
H. Joy, Carnegie astronomer, "can be
seen only in case they happen to be
near us. The brightest stars are not
always the nearest, for it is easy to
see that a giant at great distance
will appear to be only as bright as
a nearby dwarf OF the l,500 bright
est stars in the sky only 100 are
dwarfs. and of these only Is are
less luminous than our sun.
But when we consider only the
stars close to the sun we find a very
different result. Nearly all the stars