The Chickasha daily express. (Chickasha, Indian Territory [Okla.]) 1899-current, 1905-05-05
EXAMPLES OF THE
TYRANNY OF NATURE.
o o 0 @ 0
Samuel Stern Maxwell,
in Harper's Magazine.
O O @ 0 O

4 N animals do not move
1ClS themselves, but are
moved by the unseen
hand of nature. There are forces
which either continuously or inter
mittently act upon organisms and
which produce effects closely anal
ogous to those of the galyanic current
Within the past few years a number
of careful workers have observed and
described the effects of light, heat
gravitation, contact, moisture and con-
trolling the movements Of certain of
the lower animals.
LIGHT A CONTROLLING FACTOR.
The influence of light upon plant
movement is a matter of daily obserya-
ton. Less familiar is the fact that
many plants, possessed Of animal-like
power of locomotion, not merely turn
but swim freely toward the source Of
light Taking their cue from the botan-
lists, who have investigated this phe-
nomenon closely, the Psychologists
have found that many animals behave
exactly like plants in this regard, re-
spending to the direction of a light wave
with a precision almost equal to that
of the needle to the magnetic current.
Especially is this true Of myriads OF
the little organisms which everywhere
abound in sea water, and the study
of their activities has been fruitful
Of suggestive results. Some Of these
animals are positively and others mega
lively heliotropic-that is, some are
compelled to 90 towards the light and
others away from it; and, strange to
say, some are positive at one time and
negative at another.
OF the negative form, the larvae of
the great horseshoe crab are good ex-
amples. If a dish of sea water in
which these larvae are swimming be
placed in such a position that it is
illuminated by rays Of light from a sin
gle window, it will be noticed that
soon the specimens have crowded to
the side farthest from the window
That their position has been deter
mined by the direction Of the light
waves and not merely by differences
of illumination has been established
by several methods Of proof
A DEMONSTRATION.
In the water in a shallow dish are
placed number of specimens which
manifest the tendency to swim away
from the light. over the dish is placed
q hollow prism filed with a somewhat
Opaque liquid. In the shutter is a
window through which the apparatus
is illuminated and light from all other
sources is excluded. With this ar
rangement the darker side of the dish
is the one toward the window, be-
cause the thick side of the prism cuts
out larger proportion of the light;
but the direction Of the rays entering
the water is practically the same as
it would be with the prism removed.
without the intercepting prism, the
animals, being negatively heliotropic,
collect at the dark side of the dish
that is, the side farthest from the Win
dow. When the prism is put into place
the animals do not collect at the dark
(the window side of the dish, but
again proceed directly in The course
of the light rays-that is to say, they
swim from the window side. which,
by this arrangement, is relatively dark,
to the room side, which is relatively
bright. BY similar methods it has been
shown that certain other organisms are
positively heliotropic; they move to-
ward the source of light, not because
the direction Of the light rays deter
mines their movements; and this .oc-
ours even when the movement takes
them from bright to dim light.
BEYOND ANIMAL CONTROL.
1t is no longer rational to speak of
such movements as voluntary. or to
classify the forms which exhibit them
by such anthropomorphic terms as
darkloving or light-loving. The pro-
verbal moth does not cremate itself
in the candle because Of its excessive
folly. but because of its intense hello
tropism. If the moth is a conscious and
moral agent its sin does not consist
in the act Of rushing into the fame,
but in going near enough to allow the
light rays to set in operation processes
beyond its control. Here the social re-
former may easily append moral.
One of the most curious facts in the
effect OF light is that upon certain ami
mails its action is reversible. Thus the
larvae of some of the barnacles are
positive to dim and negative to bright
light. Under the influence Of the rays
which penetrate the water they are
compelled to swim toward the surface.
Before reaching it, however, the in.
creased intensity Of the light changes
them to the negative condition and
they swim downwards, until in the
weak illumination they again become
positive. Thus they go dancing up
and down, the plaything of physical
forces.
POSITIVE AND NEGATIVE.
The larvae of a certain marine worm