Evening star., 1902-06-06
HAVE PLANTS NERVES.
Phenomena Observed When Wounds
Are Made on Vegetation.
From the Literary Digest.


1t has been said that the only real differ
ence between a plant and an animal is that
the former cannot move about. Even this
does not hold universally, for some of the
lower water plants swim about quite freely.
But it Is certain that many organs that We
are accustomed to regard as distinctively
animal exist, at least in a rudmentary
form, in plants. This would appear to be
the case with the nerves, for recent expert
ment seems to show that plants have
nervous system, although 1t is of the most
primitive kind. A recent investigator, NJ.
Nemec, has just published an account of
some researches along this line which is
reviewed in the Revue Scientifique. Says
the writer:
1T has long been known that certain
parts of plants may be irritated by various
means, and that the excitation can be
transmitted across zone that has no
power of reac ton, to more or less distant
point where 1t produces motion. From this
1t is only step to the assertion that plans
have at least a rudimentary nervous sys-
tenn. Some believe that the propagation is
accomplished by successive dehydration of
the protoplasm: others think that as the
protoplasm is continuous from cell to cell, 1T
may serve in some other way as the agent
Of a transmission analogous to that which
takes place In the nervous system.
the question by experiments on the effect of
wounds on the protoplasm. He proves that
when roots and other organs are wounded
in the course of his Investigations, two
suits follow. The first is an accumulation
of protoplasm, and perhaps also a nucleus,
at the cut or wounded surface, and this
movement Is propagated with decreasing
velocity from the wounded part to the
healthy parts. The speed varies in differ
ent tissues. 1t is curious fact that If the
wave of condensation Gf We may call is SO
for simplicity meets a cell which is in pro-
cess of division it does not affect this cell
1t seems to disappear, so far the cell is
concerned, and reappears in the following
cell. Just after the cell content is
modified (and this is the second phenome-
nom, it returns to it's previous state But
this return is OF short duration; second
modification takes place in which the proto-
plasm assumes a somewhat gelatinous ap-
pearance.
This second phenomenon is more local
than the former: 1t is propagated less
quickly and not so far the other; and
NJ. Nemec thinks that the first may be due
to a disturbance of hydrastic balance in the
cells, while the second is rather caused by
the febrie condition that is provoked by
the wound. Messrs. Loeb and Mathews
would say that II was a coagulation due to
rupture of equilibrium of the IONS
An important fact In connection with the
possibility Of a rudimentary nervous sys-
tenn in plants is discovery by NJ. Nemec
that the cells are traversed ty fbrils which
may possibly even pass from one cell TO an
other. These fibrils, which can be seen only
by careful staining with an appropriate
liquid, are seen more frequently in the ex-
citable and mobile parts of the plant, and
SO they would seem to be the agents Of ex-
citation and motion. In the genus vicia
the fbrils run along the axis of the root
and NJ Nemec found that when a ring
shaped incision was made around the out
side, so as not TO touch them, the root kept
its power of receiving and transmitting
stimulation. while if the axis of the root
was pierced, so as to wound the fibrils all
excitability was lost. When the point Of
the root was cut Off sensitiveness to gravi-
ty was also lost, since it resides only in the
tip of the root; but when the tip had re-
grown, the sensitiveness did not reappear.
In this case NJ Nemec found that the con-
tinuity of the fibrils was lost; the new ones
did not join the old ones, that the tip
of the root was like the end of a finger
whose nerves have been severed by a cut
1t could not transmit its message to the rest
of the plant.