What is the actual dynamic attitude of the primary organic
engine--the vegetable organism? We consider, here, in the first
place, not intervening, but resulting phenomena.
The young leaf exposed to solar radiation is small at first, and
the quantity of radiant energy it receives in unit of time cannot
exceed that which falls upon its surface. But what is the effect
of this energy? Not to produce a retardative reaction, but an
accelerative response: for, in the enlarging of the leaf by
growth, the plant opens for itself new channels of supply.
If we refer to "the living protoplasm which, with its unknown
molecular arrangement, is the only absolute test of the cell and
of the organism in general,[1] we find a similar attitude towards
external sources of available energy. In the act of growth
increased rate of assimilation is involved, so that there is an
acceleration of change till a bulk of maximum activity is
attained. The surface, finally, becomes too small for the
absorption of energy adequate to sustain further increase of mass
(Spencer[2]), and the acceleration ceases. The waste going on in
the central parts is then just balanced by the renewal at the
surface. By division, by spreading of the mass, by
[1] Claus, _Zoology_, p. 13.
[2] Geddes and Thomson, _The Evolution of Sex_, p. 220.
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out-flowing processes, the normal activity of growth may be
restored. Till this moment nothing would be gained by any of
these changes. One or other of them is now conducive to
progressive absorption of energy by the organism, and one or
other occurs, most generally the best of them, subdivision. Two
units now exist; the total mass immediately on division is
unaltered, but paths for the more abundant absorption of energy
are laid open.
The encystment of the protoplasm (occurring under conditions upon
which naturalists do not seem agreed[1]) is to all appearance
protective from an unfavourable environment, but it is often a
period of internal change as well, resulting in a segregation
within the mass of numerous small units, followed by a breakup of
the whole into these units. It is thus an extension of the basis
of supply, and in an impoverished medium, where unit of surface
is less active, is evidently the best means of preserving a
condition of progress.
Thus, in the organism which forms the basis of all modes of life,
a definite law of action is obeyed under various circumstances of
reaction with the available energy of its environment.
Similarly, in the case of the more complex leaf, we see, not only
in the phenomenon of growth, but in its extension in a flattened
form, and in the orientation of greatest surface towards the
source of energy, an attitude towards
[1] However, "In no way comparable with death." Weismann,
_Biological Memoirs_, p. 158.
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available energy causative of accelerated transfer. There is
seemingly a principle at work, leading to the increase of organic
activity.
Many other examples might be adduced. The gastrula stage in the
development of embryos, where by invagination such an arrangement
of the multiplying cells is secured as to offer the greatest
possible surface consistent with a first division of labour; the
provision of cilia for drawing upon the energy supplies of the
medium; and more generally the specialisation of organs in the
higher developments of life, may alike be regarded as efforts of
the organism directed to the absorption of energy. When any
particular organ becomes unavailing in the obtainment of
supplies, the organ in the course of time becomes aborted or
disappears.[1] On the other hand, when a too ready and liberal
supply renders exertion and specialisation unnecessary, a similar
abortion of functionless organs takes place. This is seen in the
degraded members of certain parasites.
During certain epochs of geological history, the vegetable world
developed enormously; in response probably to liberal supplies of
carbon dioxide. A structural adaptation to the rich atmosphere
occurred, such as was calculated to cooperate in rapidly
consuming the supplies, and to this obedience to a law of
progressive transfer of energy we owe the vast stores of energy
now accumulated
[1] Claus, _Zoology_, p. 157
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in our coal fields. And when, further, we reflect that this store
of energy had long since been dissipated into space but for the
intervention of the organism, we see definitely another factor in
organic transfer of energy--a factor acting conservatively of
energy, or antagonistically to dissipation.
The tendency of organized nature in the presence of unlimited
supplies is to "run riot." This seems so universal a relation,
that we are safe in seeing here cause and effect, and in drawing
our conclusions as to the attitude of the organism towards
available energy. New species, when they come on the field of
geological history, armed with fresh adaptations, irresistible
till the slow defences of the subjected organisms are completed,
attain enormous sizes under the stimulus of abundant supply, till
finally, the environment, living and dead, reacts upon them with
restraining influence. The exuberance of the organism in presence
of energy is often so abundant as to lead by deprivation to its
self-destruction. Thus the growth of bacteria is often controlled
by their own waste products. A moment's consideration shows that
such progressive activity denotes an accelerative attitude on the
part of the organism towards the transfer of energy into the
organic material system. Finally, we are conscious in ourselves
how, by use, our faculties are developed; and it is apparent that
all such progressive developments must rest on actions which
respond to supplies with fresh demands. Possibly in the present
and ever-
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increasing consumption of inanimate power by civilised races, we
see revealed the dynamic attitude of the organism working through
thought-processes.
Whether this be so or not, we find generally in organised nature
causes at work which in some way lead to a progressive transfer
of energy into the organic system. And we notice, too, that all
is not spent, but both immediately in the growth of the
individual, and ultimately in the multiplication of the species,
there are actions associated with vitality which retard the
dissipation of energy. We proceed to state the dynamical
principles involved in these manifestations, which appear
characteristic of the organism, as follows:--
_The transfer of energy into any animate material system is
attended by effects conducive to the transfer, and retardative of
dissipation._
This statement is, I think, perfectly general. It has been in
part advanced before, but from the organic more than the physical
point of view. Thus, "hunger is an essential characteristic of
living matter"; and again, "hunger is a dominant characteristic
of living matter,"[1] are, in part, expressions of the statement.
If it be objected against the generality of the statement, that
there are periods in the life of individuals when stagnation and
decay make their appearance, we may answer, that
[1] _Evolution of Sex._ Geddes and Thomson, chap. xvi. See also a
reference to Cope's theory of "Growth Force," in Wallace's
_Darwinism_, p. 425.
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such phenomena arise in phases of life developed under conditions
of external constraint, as will be urged more fully further on,
and that in fact the special conditions of old age do not and
cannot express the true law and tendency of the dynamic relations
of life in the face of its evident advance upon the Earth. The
law of the unconstrained cell is growth on an ever increasing
scale; and although we assume the organic configuration, whether
somatic or reproductive, to be essentially unstable, so that
continual inflow of energy is required merely to keep it in
existence, this does not vitiate the fact that, when free of all
external constraint, growth gains on waste. Indeed, even in the
case of old age, the statement remains essentially true, for the
phenomena then displayed point to a breakdown of the functioning
power of the cell, an approximation to configurations incapable
of assimilation. It is not as if life showed in these phenomena
that its conditions could obtain in the midst of abundance, and
yet its law be suspended; but as if they represented a
degradation of the very conditions of life, a break up, under the
laws of the inanimate, of the animate contrivance; so that energy
is no longer available to it, or the primary condition, "the
transfer of energy into the animate system," is imperfectly
obeyed. It is to the perfect contrivance of life our statement
refers.
That the final end of all will be general non-availability there
seems little reason to doubt, and the organism, itself dependent
upon differences of potential, cannot
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hope to carry on aggregation of energy beyond the period when
differences of potential are not. The organism is not accountable
for this. It is being affected by events external to it, by the
actions going on through inanimate agents. And although there be
only a part of the received energy preserved, there is a part
preserved, and this amount is continually on the increase. To see
this it is only necessary to reflect that the sum of animate
energy--capability of doing work in any way through animate
means--at present upon the Earth, is the result, although a small
one, of energy reaching the Earth since a remote period, and
which otherwise had been dissipated in space. In inanimate
actions throughout nature, as we know it, the availability is
continually diminishing. The change is all the one way. As,
however, the supply of available energy in the universe is
(probably) limited in amount, we must look upon the two as simply
effecting the final dissipation of potential in very different
ways. The animate system is aggressive on the energy available to
it, spends with economy, and invests at interest till death
finally deprives it of all. It has heirs, indeed, who inherit
some of its gains, but they, too, must die, and ultimately there
will be no successors, and the greater part must melt away as if
it had never been. The inanimate system responds to the forces
imposed upon it by sluggish changes; of that which is thrust upon
it, it squanders uselessly. The path of the energy is very
different in the two cases.
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While it is true generally that both systems ultimately result in
the dissipation of energy to uniform potential, the organism can,
as we have seen, under particular circumstances evade the final
doom altogether. It can lay up a store of potential energy which
may be permanent. Thus, so long as there is free oxygen in the
universe, our coalfields might, at any time in the remote future,
generate light and heat in the universal grave.
It is necessary to observe on the fundamental distinction between
the growth of the protoplasm and the growth of the crystal. It is
common to draw comparison between the two, and to point to
metabolism as the chief distinction. But while this is the most
obvious distinction the more fundamental one remains in the
energy relations of the two with the environment.[1] The growth
of the crystal is the result of loss of energy; that of the
organism the result of gain of energy. The crystal represents a
last position of stable equilibrium assumed by molecules upon a
certain loss of kinetic energy, and the formation of the crystal
by evaporation and concentration of a liquid does not, in its
dynamic aspect, differ much from the precipitation of an
amorphous sediment. The organism, on the other hand, represents a
more or less unstable condition formed and maintained by inflow
of energy; its formation, indeed, often attended with a loss of
kinetic energy (fixation of carbon in plants), but, if so,
accompanied by
[1] It appears exceptional for the crystal line configuration to
stand higher in the scale of energy than the amorphous.
74
a more than compensatory increase of potential molecular energy.
Thus, between growth in the living world and growth in the dead
world, the energy relations with the environment reveal a marked
contrast. Again, in the phenomena of combustion, there are
certain superficial resemblances which have led to comparison
between the two. Here again, however, the attitudes towards the
energy of the environment stand very much as + and -. The life
absorbs, stores, and spends with economy. The flame only
recklessly spends. The property of storage by the organism calls
out a further distinction between the course of the two
processes. It secures that the chemical activity of the organism
can be propagated in a medium in which the supply of energy is
discontinuous or localised. The chemical activity of the
combustion can, strictly speaking, only be propagated among
contiguous particles. I need not dwell on the latter fact; an
example of the former is seen in the action of the roots of
plants, which will often traverse a barren place or circumvent an
obstacle in their search for energy. In this manner roots will
find out spots of rich nutriment.
Thus there is a dynamic distinction between the progress of the
organism and the progress of the combustion, or of the chemical
reaction generally. And although there be unstable chemical
systems which absorb energy during reaction, these are
(dynamically) no more than the expansion of the compressed gas.
There is a certain
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initial capacity in the system for a given quantity of energy;
this satisfied, progress ceases. The progress of the organism in
time is continual, and goes on from less to greater so long as
its development is unconstrained and the supply of energy is
unlimited.
We must regard the organism as a configuration which is so
contrived as to evade the tendency of the universal laws of
nature. Except we are prepared to believe that a violation of the
second law of thermodynamics occurs in the organism, that a
"sorting demon" is at work within it, we must, I think, assume
that the interactions going on among its molecules are
accompanied by retardation and dissipation like the rest of
nature. That such conditions are not incompatible with the
definition of the dynamic attitude of the organism, can be shown
by analogy with our inanimate machines which, by aid of
hypotheses in keeping with the second law of thermodynamics, may
be supposed to fulfil the energy-functions of the plant or
animal, and, in fact, in all apparent respects conform to the
definition of the organism.
We may assume this accomplished by a contrivance of the nature of
a steam-engine, driven by solar energy. It has a boiler, which we
may suppose fed by the action of the engine. It has piston,
cranks, and other movable parts, all subject to resistance from
friction, etc. Now there is no reason why this engine should not
expend its surplus energy in shaping, fitting, and starting into
action other engines:--in fact, in reproductive sacrifice. All
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these other engines represent a multiplied absorption of energy
as the effects of the energy received by the parent engine, and
may in time be supposed to reproduce themselves. Further, we may
suppose the parent engine to be small and capable of developing
very little power, but the whole series as increasing in power at
each generation. Thus the primary energy relations of the
vegetable organism are represented in these engines, and no
violation of the second law of thermodynamics involved.
We might extend the analogy, and assuming these engines to spend
a portion of their surplus energy in doing work against chemical
forces--as, for example, by decomposing water through the
intervention of a dynamo--suppose them to lay up in this way a
store of potential energy capable of heating the boilers of a
second order of engines, representing the graminivorous animal.
It is obvious without proceeding to a tertiary or carnivorous
order, that the condition of energy in the animal world may be
supposed fulfilled in these successive series of engines, and no
violation of the principles governing the actions going on in our
machines assumed. Organisms evolving on similar principles would
experience loss at every transfer. Thus only a portion of the
radiant energy absorbed by the leaf would be expended in actual
work, chemical and gravitational, etc. It is very certain that
this is, in fact, what takes place.
It is, perhaps, worth passing observation that, from the
nutritive dependence of the animal upon the vegetable,
77
and the fact that a conversion of the energy of the one to the
purposes of the other cannot occur without loss, the mean energy
absorbed daily by the vegetable for the purpose of growth must
greatly exceed that used in animal growth; so that the chemical
potential energy of vegetation upon the earth is much greater
than the energy of all kinds represented in the animal
configurations.[1] It appears, too, that in the power possessed
by the vegetable of remaining comparatively inactive, of
surviving hard times by the expenditure and absorption of but
little, the vegetable constitutes a veritable reservoir for the
uniform supply of the more unstable and active animal.
Finally, on the question of the manner of origin of organic
systems, it is to be observed that, while the life of the present
is very surely the survival of the fittest of the tendencies and
chances of the past, yet, in the initiation of the organised
world, a single chance may have decided a whole course of events:
for, once originated, its own law secures its increase, although
within the new order of actions, the law of the fittest must
assert itself. That such a progressive material system as an
organism was possible, and at some remote period was initiated,
is matter of knowledge; whether or not the initiatory living
configuration was rare and fortuitous, or the probable result of
the general action of physical laws acting among innumerable
chances, must remain matter of
[1] I find a similar conclusion arrived at in Semper's _Animal
Life_, p. 52.
78
speculation. In the event of the former being the truth, it is
evidently possible, in spite of a large finite number of
habitable worlds, that life is non-existent elsewhere. If the
latter is the truth, it is almost certain that there is life in
all, or many of those worlds.