Evening star., 1939-07-20
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henri.

PARIS, July 20.-Discovery of bridge
of life where plant may change ir-
reversibly into an animal has just been
reported to the French Association for
the Advancement of Science by DR..
Andre Lwof of the Pasteur Institute.
He has been able in his laboratory to
bring about the change by which a
sngle-celled water plant loses progress
sively the green pigment which enables
it to absorb carbon dioxide from the air
and is forced to vegetable diet in or
der to survive.
This transition in nature, more than
half billion years ago, may have been
the most important event in the evo-
luton of life on earth, making possible
eventually the higher animals and man
rather than planet on which the only
life was vegetation.
In the microscopic world, DR.. Lwoff
explains in his report, most of the or
dinary distinctions between plants and
animals disappear The one which per-
sists and forms supposedly insur-
mountable barrier between the two king
doms of life, is the possession by plants
OF the pigment chlorophyll. This is the
green" OF nature. BY means of it a
plant can breath carbon out of the air
and, through the energy of sunlight,
combine it with hydrogen into the
starches and sugars which constitute
the fuel of all animal life.
No animal has the power of doing
this. Consequently all animals must eat
plants, either directly or in the form of
other animals which have eaten them.
The plant then must have come first
since they can exist without animals but
ANIMALS cannot exist without them At
some time plant must have changed
into an animal.
DR.. LWoff found the bridge between the
two Kingdoms in a very common, free
moving water organism which is dis
trlbuted all over the earth-the euglena,
IL Is relatively large single-celled plant
as much as a tenth of millimeter in
length and just on the verge of being
visible to the naked eye. 1t reproduces
Itself, in common with other one-celled
1orms OF life, by splitting in two, each
nan becoming an independent plant,
Scattered through its protoplasm are
tiny plaques, each colored bright green
with chlorophyll. Ordinarily at the time
OF division each plaque splits in two,
half OF each going to both of the new
plants.
Now, DR.. Lwoff reported, when this
ic
occasional specimens are found with
coiorless plaques. They have no chloro-
phyu. The plaques themselves, however.
seem to possess the chemical precursor
OF the green pigment and are able to
absorb and transform carbon dioxide,
although rather inefficiently.
Some of the microscopic plants have
lever plaques than others. Very rarely
specimen is found with only one It is
sui, however, plant capable of getting
It's carbon from gas in the atmosphere.
But at this point a curious thing NAV
happen. The chances are vastly against
it, but DR.. Lwoff has seen it happen in
the laboratory and at some time or other
II PROBABLY happened in nature
The process of cell division gets of
its very precise time schedule. The
protoplasm of the cell divides faster than
the single chlorophyll plaque The result
is that one of the new individuals is left
without any means Of absorbing and fix
Ing gaseous carbon. 1t has become an
animal-the most primitive sort of ami
NAL conceivable and must find entirely
new ways of feeding itself
DR.. Lwoff can produce, he reported,
the transition from plant to animal in
from three to six months and can con-
tlnue the animal line. The transforma-
ton must always be in one direction
from plant to animal. There is no turn
ing back to the comfortable vegetative
state where life is without sensation or
adventure.
Henceforth the creature must live by
burning the starches and sugars it's
plant ancestors have manufactured. For
this 1t must evolve digestive apparatus
and then, through millions of gener-
atlons, nervous system and brain.
One OF the striking changes, Dr. Lwoff
explains, is the need for vitamins. During
the last few years, he says, numerous
one-celled creatures have been found
which, like men, require minute amounts
of these chemical substances in their
food-chief1y vitamins and Gin order
to survive
His studies demonstrate, DR.. Lwoff
says, that there is constantly existing
intermediate state between the plant
and animal kingdoms out of which ami
NAL life emerges usually to perish on
the other side unless it can find a niche
for itself which is not occupied by exist
ing animals with whom it would be
unable to compete.