Evening star., 1928-11-04

ing on the intensity of the radiation.
In some cases the injury results in 80
seconds. The ultraviolet. he said, evil
dntly prevents the production of carbo-
hydrates and eventually will kill the
plant. The injury decreases rapidly as
the radiation is brought down within
the limits of sunlight.
Influence of light on the behavior of
animals was described by Prof. w. j.
Cro2ier Of Harvard University. This
is not conscious but mechanical be-
havior, and is not dependent on the will
of the animal" he said
He described experiments where one
eye was removed from a water scor-
pion and where the bug. illuminated
from above, swan naturally in a cir
cular path Another experiment was
with newly born rats whose eyes had
not opened, but whose eyelids were
sensitive to light. One eye was re-
moved under an anesthetic and the
animal illuminated from above. The re-
suit was that 1t moved in a spiral
course, the spiral Tightening as the light
stimulus was increased. Thus there was
a direct relation between the intensity
of the light and the amplitude OF the
turning movement, due to the excita-
ton of muscles on one side. Such
tropisms, DR.. Crozier believes, do not
stop with the lower animals, but may
be traced in the behavior of men.
The chemist and the physicist to-
gether face the problem Of obtaining
pure chlorphyll. the coloring matter in
the leaves of plants, which because OF
its action on sunlight is one of the
most important elements In all life, DR..
F. M. Schertz of the Department OF
Agriculture told the society. The great
difficulty he said lies in the fact that
chlorphyll undergoes decomposition at
every stage Of its progress. Eventually,
he said some natural product from
chlorphyll may be found in every living
cell The problem may be. solved. he
said, by a spectroscopic study, which is
likely to reveal that every group Of
plants has a chemistry OF its own.
Pigment in Wheat Flour.
DR.. H. j. McNicholas of the Bureau
of Standards told of Spectroscopic stud
les of carotin and xanthophyll, two OBJ
scure yellow pigments in plant life the
significance of which Is not known.
Carotin Is the only pigment in wheat
flour and must be bleached away to
produce the commercial white flour.
Ultra violet light In sunlight IN Balti-
more varies from 400 ergs per square
centimeter a second In January to 1000
ergs in August, Janet Howell Clark OF
Johns Hopkins University told the So
ciety. The maximum Is not reached at
the time of highest altitude OF the sun
in June, she said, probably because tnere
is a maximum thickness OF ozone in
N Cnrinp
a minimum In the Fall so that by
August this natural guard against the
extremely short light waves has greatly
decreased Biologically effective rays in
sunlight almost entirely disappear by
pm. in the Winter, she said.
The behaviorist school OF psychology
by no means covers the whole field and
its procedure belongs with biology, said
Prof. Leonard T. Troland of Harvard
University, speaking on the relation of
optics to psychology. He stressed the
Importance Of the subjective or intro
spective school Of psychology, which
stresses what goes on in the mind rather
than confines itself to the external
stimuli.
Phenomena Explanation.
How do the behaviorists, he said. ex-
plain the phenomena OF color or OF
tone in music? Color, he pointed out,
to the physicist depends on certain wave
lengths of light, yet the actual colors
we see are mental rather than physical
things 1t is possible, he said. by electr1-
cal stimulation of the eye or the visual
center of the brain, to make a person |
see any wave lengths OF purples or
blues, because color exists inside tne
brain. If color was purely matter OF
wave length, he said 1t would be pos
sible to see ultra violet and infra-red |
as well as the visible spectrum. The |
same Is true, he pointed out, OF musi- |
cal tones. Thoughts, imagination, feel |
ing and will, he insisted, cannot be |
identified with physical relationships. |
but depend upon operation within the
central nervous system,
No problem in psychology said Prof |
Troland, Is more important than a
thorough understanding OF the, visual
field of human experience. including an |
explanation Of such pnenomena as
luSter and glow.
Efforts to show the assembled physicists |
a "ghost" met with Indifferent success |
yesterday afternoon.
This phenomenon Is blue arc which |
appears at the sides OF a shaft OF red |
or yellow light on screen in dark |
erled room when the person fixes his |
gaze on the proper spot. 1t is COM |
plex optical phehomenon related to the
we'll known "after-image" in psychology, |
which probably is responsible for some |
of the historical visions. When con-
ditions are right the blue are always |
appears with more or less intensity to |
the majority of persons, but yesterday !
some saw 1t and some didn't,
An explanation was offered by Deane |
q. Judd of the Bureau of Standards |
to the effect that the phenomenon is I
due to nerve activity which originates |