The morning news. [volume] (Savannah, Ga.) 1887-1900, 1897-02-14
THE rNrELLrGrxcr or PLANTS.
How They Think For Themselves.
NInrNeIons Powers of Lilo ChoIcc.

Plants, just as much as ANIMALS, are
irritable beings, and like animals. they
may show irritability 10 varying degrees.
Thus some plants may be described as
mildly irritable others as rapidly irritable.
and few as even restlessly irriable Ev-
cry plant has to look after its feeding.
Green plants, Furthermore, have to seek
for very Important part OF their food
in the air and this they take up under
the influence of light; SO that It is not
surprising TO find the iniueHce of environ
ment making itself felt on every plant.
causing the plant in one way OF another
to react to its SURROUNDINGS. II is the
particular response 10 stimuli which we
may call irritability. A plant Is irritable
because IL is able to respond TO a slim
ulus
Take the case of voucheria a lowly or
GaniZed plant frequently found forming
large dark green patches upon flower pots
WHEN the plant is PUT into water 1t begins
TO change its character altogether, and
in the tips of its filamentS aggregatons
of protOplasm are seen to form These
become more and more dense the tilament
then bursts and discharges a green pro-
toplasnic mass, which swins by means of
ella and finally settles down. The motile
plantlet does not do this indiscriminatelN
or in a hurry, but shows a. great method
in settling down. Before coming to rest,
each little protoplasmic body has thought
for itself and has decided to settle on
the basin a little way below the surface
the maximum amount of light which is
to enable il to make the substance il re-
quires for its growth. We may say, then.
of this spore that 1t has had to hunt for
its food and finally settled down on a
suitable spot.
Higher plants no less than lower are ir-
ritable. The shoots Of tree, responding
to the influence of light, place the leaves
IN the most advantageous position for the
work they have to perform, and the roots,
in obedience to the stimulus exerted by
MT he
earth Tendrils are modified leaves or
branches which have become irritable to
contact.
A little plaht, the ivy-leavod toad-flax.
found covering limestone walls, with tufts
of bright green foliage and purple flowers.
amords an interesting instance Of irrita-
Dllty. When IN blossom, the long flower
stalks OF the plant turn outward and carry
the flowers from underneath the leaves in
order that they may secure the visits of
insects, which are necessary for their fer
tilization. The stalk of the seed vessel is,
fortunately for the welfare of the plant.
an irritable structure. When towering is
over IL no longer seeks the place which is
most strongly lighted, but carries the ri
penng fruit behind the leaves into a lit
tie Granny of the wall. Here the seed yes
sci bursts and discharges its contents not
among coarser weeds, where it's growth
would be inevitably checked. but upon the
son which has collected in the Granny.
Houng seedlings soon make their appear
ance' ana, as result of this furnishing
start in life, the ivy-leaved toad-hax is u.s.
uaily. round abundantly in districts where
II is found at all. Here we have flower
stalk responding to the stimulus of light
ana a reversal of the influence at different
periods of Development enabling the plant
10 accommodate itself to its environments
Ala plants only succeed so long as their
lrr1tabllity leads them to- adapt themseIses
TO the surroundings. The more lowlv or
ganized, by reason of their simpler struc-
lure snow greater versatility in this re-
spect than their more complex relative II
lss easy 70 understand how little mass
OF protplasm can more readily adapt itself
70 varying conditions of life than a higher
plant with its extensive differentiation of
tissue -
Bacteria are. especially sensitive from
ms point OF view. They can distinguish
WITH great nicely between the relative
suitability of two nutrient solutions
MANY OF them are capable Of perfectly as.
founding discrimination i'm this respect. In
me same way the white blood corpuseles
are attracted by certain foreign--often
9genicrsubstances TO the spot of the
Intrusion OF bacteria into the blood. Here
II IS the business of the white corpuscles
II possible, to destroy the Bacteria This
al dctIoh SHOWN py many organisms to-
Mard chemical substances is known as
The spores of ferns and moses afford a
aTiie l thdoIe illustration. The male cells
are discharged by the plant and NAV be
seen swimming i'll all directions in water
Wneh suddenly they will make a dash in
InS ,olrecIlon OF the female organ This
suuuen rush is a chemoitactic phenome~
non non; IN the case of ferns malic acid ana
IN the case Of MOSES a sugar, is the sub
same secreted by the female organ caus-
lnS Tue surprising activity of the little
swimming antherozoids. Wonderfully d.
Iute solutions are capable of causing the
soiIllulus. surprising the strength of the
solutlon be gradually increased a limit
Is shortly reached, beyond which the So
Iutloh acts as a repellent instead of an
sotirac.Re STIMULUS, causing the plants to
SWIM away as far as they can. IT, how
ever the plants be compelled to live in =
cifiLUns soiutlon4 they will In time get ae
v Iard 'i ~ ana Will swim vigorously TO-
MdIu a. solution of the attracting salt
although 1t may very much exceed the
h0TndI maximum of attracting strength
Inc following is an example of chemi-
otaAIs winch plant has discovered to Sc
cure its own ends. Isaria Is a fungus
Wnlch lnfests silkworms and other cater
pdiIdrs; Melanospora Is another fungus
parasitic upon fsaris, an extremely intei-
nsent parasite, and unless IL happens 10
meet with a filament of isaris Il entirely
misses It's vocation. Now melanospora APP
Parently secretes some substance which
exercises considerable attraction for isaris
Ilaments, for they seek out the apparent-
~ harmless spores of melanospora and
grow freely over them. When the spore
IS surrounded by isaris hlaments. II puts
OUT us germ tube and proceeds to feed up
on its host.
Not so obviously intelligent although II
Is IN reality. is the life of the green plants
The TACT that the branches of a tree
grow upward into the air and light, while
the roots grow downward into the soil
shows that the different parts are endowed
with special irritability. Green plants
also possess the power Of adapting them
selves to circumstances. a potato, when
grown in the cellar IN the attempt to get
its leaves into the light puts out very
much elongated shoots bearing small
leaves, for In the darkness leaves are una
bic to perform the important functions of
taking food from the air. This behavior or
the potato plant is. then, direct attempt
TO overcome Instantaneous conditions
by putting all its strength into the work
OF elongating its stem. " haply il may
bring its leaves to the light.
Roots show remarkable Intelligence "a
the way in which they move through the
ground. II is necessary for the proper
performance of its duties that root he
supplied with oxygen. 1t has no dini-
Guilty in obtaining this oxygen from a
healthy soil In the tropical mangrove
swamps the soil consists OF mass OF
decayed vegetation, where very little oxv-
gen is found among tho putrefying sub
stance. The mangroYe accordingly adapts
itself 20 circumstances. It's roots begin
by growing horizontally in the normal
wav, but If not aerated they proceed 10
take turn upward. grow along In the air
for a short distance above the ground
and then go down again. A root may re-
peat this process at intervals. In the
aerial parts is found permeable tissue
which allows OF the free circulation of air
between the cells