Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-05-03
SPONTANEOUSL|FE
DENIED BY DROPLET
Physical Society Given Yer.
sion of Start of Living
Organism.
BY THOMAS r. HENRY.


could have been an accident
Such was the implication of profound
mathematical and physical considera-
tions presented before the American
Physical Society at its closing meeting
yesterday afteroon by DR.. N. Rashevsky
of the Westinghouse Research Labora-
tories. DR.. Rashevsky's mathematics
led to the supposition that at least an
introduced physical system must have
marked the start of the infinite sue
cession of cell divisions that has con-
stituted the flow of life through time
from the appearance of the first bit Of
living matter to the highly complex
organisms of today.
DR.. Rashevsky described the behav-
for of hypothetical drop of liquid,
discrete system, in a liquid of similar
composition and specific gravity. The
drop and the liquid surrounding would
interact. The drop would absorb from
the surrounding medium and grow. AT
the same time 1t would undergo the
process Of dissolution at its surface.
Similarity of Behavior.
Now DR.. Rashevsky showed, under
appropriate conditions, this drop would
behave in a manner very similar to a
cell, which Is the unit OF all living
things. The cell Is approximately such
TRENT substances from the blood stream.
When it reaches a certain critical size
1t breaks in two, each half becoming
complete cell and undergoing the same
process in its turn. The one-celled
plants and animals reproduce in this
way. This also is the method of in
crease of body cells. DR.. Rashevsky
pointed to the similarity of the behavior
of cancer cells, as shown in recently
taken moving pictures to that OF MS
hypothetical liquid drops.
The liquid drop is naturally spherical
IN shape On its outside surface 1t Is
dissolving into the surrounding medium.
This dissolution Is going on all over the
surface and nowhere else. While 1t dis
solves here it Is growing from the inside
due to the material which has been alb
sorbed Now the smaller the drop the
greater the surface area where the dis
solution is going on proportional to the
amount Of the internal material where
the growth is going on. If the proper
ton is such that the rate Of dissolution
is greater than the rate Of growth the
drop simply will disappear as dis
crete system and become part OF the
surrounding medium. If the reverse Is
the case it will increase. A big drop
grows and little one declines.
Discrete Physical System.
Thus, DR.. Rashevsky pointed out, in
the beginning Of chain Of diviStSH
and formation of new droplets tf.efe
must be a drop, constituting a diScrete
physical system, big enough to grow In
stead of diSap2esS:. Now mathematical
considerations show that such system
appearing spontaneously would neceS-
sarily be so small that 1t would be dis
sipated by dissolution from the surface.
1t would be necessary TO nave drop
readymade big enough to keep on
growing.
But when It keeps on growing the
drop, due to certain physical condi-
tions inherent in its makeup, reaches
a critical size where 1t will split in two
Each of the daughter drops will then
go through the same process.
when such system" DR.. Rashev-
sky said, "interacts chemically with the
surroundings in such a way that the
mass Of the substances Of which the
system Is constituted slowly increases,
the system will possess, under very gen.
eral conditions, properties remarkably
similar to those found in living organ
isms. Thus it is found that such sys-
tenn may have certain positive rate
Of growth when its size exceeds q GER
tain critical one. Below this critical
size the rate Of growth Is negative.
Such system, therefore, can never be
formed spontaneously, although all
substances necessary for its formation
may be present. Under certain very
general conditions the system will, un-
der the influence Of osmotic and other
forces, divide into two halves when
reaching certain size. In many cases
the system will possess very definite
Eeometrtcal form which will tend to
be restored when the system Is de-
formed by some external disturbance"
Models of Phvsical Life.
Or. Rashevsky emphasized that his
hypothetical liquid droplets, not actu-
ally produced by experiment, but formu-
lated only on the paper OF the mathe-
n1atician, must be considered only as
models and not as actual pictures of
possible physical life units as they exist
in nature.
Nature, 1t was emphasized. might in
troduce factors which are beyond the
skill OF the mathematical physicist in
constructing models Of what might have
happened. But the mathematical nod
els show how the life stream might have
e.arted mechanically. Chemists and
biologists have postulated a start of
life due TO the accidental chemical COM
bination of the substances which enter
into protoplasm, but DR.. Rashevsky
showed that this could not have hap
pened the start was anything like
the start Of the artificial growth and
reproduction stream Of his models.
The paper was the outstanding con-
tribution TO a symposium on colloidal
physics