Evening star., 1937-01-01
BY THOMAS r. HENRY,
Stan Correspondent Of The Star.

BY THOMAS r. HENRY,
Stan Correspondent Of The Star.
ATLANTIC CITY, January IA
new bridge between the two main di-
visions of life-the animal and the
plant kingdoms-was described before
the American Association for the Ad-
vancement Of Science here today by
DR.. H. G. du Buy of the University
Of Maryland.
Essentially the same thing which
enables an animal to see Is responsible
for the bending of q plant towards
the light. DR.. du Buy showed. In the
plant the action Is 1000 times slower.
In both cases the Maryland plant
psychologist said. the responsible
agent Is q form of caroline, the red
dish yellow pigment most familiar Is
the coloring matter in carrots and
the reason why 30 many parents in
flict these vegetables on their children.
An ample supply In the system may
be an important element in normal
eyesight.
Sight Of Animal.
Previous experiments have shown,
DR.. du Buy said, that An animal sees
largely by the action of light on visual
purple. a complex substance in the
retina OF the eye which Is broken
down by radiation. 1t IS changed
into q simpler substance. visual yellow,
which rapidly builds up into visual
purple again. One Of the chief con-
stituents of this visual yellow is 4
caroline compound, showing that caro-
tine Is q necessary constituent Of the
essential visual purple.
It also has been shown that certain
plants bend towards the light-liks .
sunfiower. which keeps its face always
turned to. the sun-because of the
action Of light on caroline in the
growing tips. Smithsonian Institu-
tion experiments have shown that the
strength of the sun turning" varies
enormously with the wave length OF
radiation used-certain bands of blue
light being 10000 times as effective
as red light. The curve Of the light
effect Is almost precisely the same
as the curve of light absorption by
the two most common forms OF caro-
tine. Caroline apparently must ab-
sorb light quanta before an animal
can see or q plant bend.
Presence Of Caroline.
DIR. du Buy demonstrated the pres
ehce OF caroline by analysis OF 1
thousand or more tips Of oat seedlings,
which to the eye appear colorless and
perfectly transparent to light. The
great difficulty in placing animal vis-
Ion and plant bending on the same
basis. he said, lay in q mistaken con-
clusion that the action OF light on
the growing end of q plant was con.
tinuous. = product Of duration times
intensity OF illumination. The plant
never seemed to tire while q funda-
mental phenomenon of vision was
the continuous tearing down and
building up Of the visual purple. A
man staring at an intensely illumi-
mated object doesn't see It all the time.
There are interludes when it oem-
pletely disappears from his physical
vision. although he may not notice
the lapse because the image Of the
object is fixed in his mind.
BY new experiments, DR.. du Buy
reported, he has demonstrated that
the plant also tires Of reacting to
light. but the process takes about
1000 times longer. He observed un-
der the microscope the phenomenon
Of "protoplAsmic streaming" in the
cells OF his oat seedlings. Normally
the protoplasm in d plant cell is cir
cling around all the time, presum-
ably carrying to different parts Of the
cell the minute amounts of the chem.
ical substances known as "auxins,"
or growth hormones, which enable the
plant to grow. This streaming Is in
hibit<d by light. Hence the tip Of q
plant on the illuminated side grows
slower than on the dark side, and
this upset Of the growth balance is
responsible for the bending.
DR.. du Buy found that there are
interruptions in this process strictly
comparable to the break down of vis-
ual purple In vision. But. whereas
the former Is 4 matter Of = half hour,
the latter ID matter of seconds, COM
parable to the relative speeds Of ami
NAL and plant life processes.
DR.. au Buy Explains Wsrk.
"a plant" said DIR. du Buy in ex-
planning his work, seems TO be Just
an animal stretched out In time"
The findings. he said, suggest .
possible common ancestor to both
vision and plant bending in the mys-
terious red spot" found on certain
one -cellsd organisms which are SEN
sitive to light. It has been described
on protozoa, or o1e-celled animals,
and on certain microscopic organisms
which seem to combine the character
istics OF both paants ana animals.
The probability = sthat It II the dot
Of caroline which pne branch Of life
has evolved into a eye sI,d tht ether
n