In order to make the title of this discourse generally intelligible, I
have translated the term "Protoplasm," which is the scientific name of the
substance of which I am about to speak, by the words "the physical basis
of life." I suppose that, to many, the idea that there is such a thing as
a physical basis, or matter, of life may be novel—so widely spread
is the conception of life as a something which works through matter, but
is independent of it; and even those who are aware that matter and life
are inseparably connected, may not be prepared for the conclusion plainly
suggested by the phrase, "THE physical basis or matter of life," that
there is some one kind of matter which is common to all living beings, and
that their endless diversities are bound together by a physical, as well
as an ideal, unity. In fact, when first apprehended, such a doctrine as
this appears almost shocking to common sense.
What, truly, can seem to be more obviously different from one another, in
faculty, in form, and in substance, than the various kinds of living
beings? What community of faculty can there be between the bright-coloured
lichen, which so nearly resembles a mere mineral incrustation of the bare
rock on which it grows, and the painter, to whom it is instinct with
beauty, or the botanist, whom it feeds with knowledge?
Again, think of the microscopic fungus—a mere infinitesimal ovoid
particle, which finds space and duration enough to multiply into countless
millions in the body of a living fly; and then of the wealth of foliage,
the luxuriance of flower and fruit, which lies between this bald sketch of
a plant and the giant pine of California, towering to the dimensions of a
cathedral spire, or the Indian fig, which covers acres with its profound
shadow, and endures while nations and empires come and go around its vast
circumference. Or, turning to the other half of the world of life, picture
to yourselves the great Finner whale,93 hugest of
beasts that live, or have lived, disporting his eighty or ninety feet of
bone, muscle and blubber, with easy roll, among waves in which the
stoutest ship that ever left dockyard would flounder hopelessly; and
contrast him with the invisible animalcules—mere gelatinous specks,
multitudes of which could, in fact, dance upon the point of a needle with
the same ease as the angels of the Schoolmen could, in imagination. With
these images before your minds, you may well ask, what community of form,
or structure, is there between the animalcule and the whale; or between
the fungus and the fig-tree? And, a fortiori,94 between
all four?
Finally, if we regard substance, or material composition, what hidden bond
can connect the flower which a girl wears in her hair and the blood which
courses through her youthful veins; or, what is there in common between
the dense and resisting mass of the oak, or the strong fabric of the
tortoise, and those broad disks of glassy jelly which may be seen
pulsating through the waters of a calm sea, but which drain away to mere
films in the hand which raises them out of their element?
Such objections as these must, I think, arise in the mind of every one who
ponders, for the first time, upon the conception of a single physical
basis of life underlying all the diversities of vital existence; but I
propose to demonstrate to you that, notwithstanding these apparent
difficulties, a threefold unity—namely, a unity of power or faculty,
a unity of form, and a unity of substantial composition—does pervade
the whole living world.
No very abstruse argumentation is needed, in the first place to prove that
the powers, or faculties, of all kinds of living matter, diverse as they
may be in degree, are substantially similar in kind.
Goethe has condensed a survey of all powers of mankind into the well-known
epigram:—95
"Warum treibt sich das Volk so und schreit? Es will sich ernahren Kinder
zeugen, und die nahren so gut es vermag. . . . . . . . . . . . . . Weiter
bringt es kein Mensch, stell' er sich wie er auch will."
In physiological language this means, that all the multifarious and
complicated activities of man are comprehensible under three categories.
Either they are immediately directed towards the maintenance and
development of the body, or they effect transitory changes in the relative
positions of parts of the body, or they tend towards the continuance of
the species. Even those manifestations of intellect, of feeling, and of
will, which we rightly name the higher faculties, are not excluded from
this classification, inasmuch as to every one but the subject of them,
they are known only as transitory changes in the relative positions of
parts of the body. Speech, gesture, and every other form of human action
are, in the long run, resolvable into muscular contraction, and muscular
contraction is but a transitory change in the relative positions of the
parts of a muscle. But the scheme which is large enough to embrace the
activities of the highest form of life, covers all those of the lower
creatures. The lowest plant, or animalcule, feeds, grows, and reproduces
its kind. In addition, all animals manifest those transitory changes of
form which we class under irritability and contractility; and, it is more
than probable, that when the vegetable world is thoroughly explored, we
shall find all plants in possession of the same powers, at one time or
other of their existence.
I am not now alluding to such phaenomena, at once rare and conspicuous, as
those exhibited by the leaflets of the sensitive plants, or the stamens of
the barberry, but to much more widely spread, and at the same time, more
subtle and hidden, manifestations of vegetable contractility. You are
doubtless aware that the common nettle owes its stinging property to the
innumerable stiff and needle-like, though exquisitely delicate, hairs
which cover its surface. Each stinging-needle tapers from a broad base to
a slender summit, which, though rounded at the end, is of such microscopic
fineness that it readily penetrates, and breaks off in, the skin. The
whole hair consists of a very delicate outer case of wood, closely applied
to the inner surface of which is a layer of semi-fluid matter, full of
innumerable granules of extreme minuteness. This semi-fluid lining is
protoplasm, which thus constitutes a kind of bag, full of a limpid liquid,
and roughly corresponding in form with the interior of the hair which it
fills. When viewed with a sufficiently high magnifying power, the
protoplasmic layer of the nettle hair is seen to be in a condition of
unceasing activity. Local contractions of the whole thickness of its
substance pass slowly and gradually from point to point, and give rise to
the appearance of progressive waves, just as the bending of successive
stalks of corn by a breeze produces the apparent billows of a cornfield.
But, in addition to these movements, and independently of them, the
granules are driven, in relatively rapid streams, through channels in the
protoplasm which seem to have a considerable amount of persistence. Most
commonly, the currents in adjacent parts of the protoplasm take similar
directions; and, thus, there is a general stream up one side of the hair
and down the other. But this does not prevent the existence of partial
currents which take different routes; and sometimes trains of granules may
be seen coursing swiftly in opposite directions within a twenty-thousandth
of an inch of one another; while, occasionally, opposite streams come into
direct collision, and, after a longer or shorter struggle, one
predominates. The cause of these currents seems to lie in contractions of
the protoplasm which bounds the channels in which they flow, but which are
so minute that the best microscopes show only their effects, and not
themselves.
The spectacle afforded by the wonderful energies prisoned within the
compass of the microscopic hair of a plant, which we commonly regard as a
merely passive organism, is not easily forgotten by one who has watched
its display, continued hour after hour, without pause or sign of
weakening. The possible complexity of many other organic forms, seemingly
as simple as the protoplasm of the nettle, dawns upon one; and the
comparison of such a protoplasm to a body with an internal circulation,
which has been put forward by an eminent physiologist, loses much of its
startling character. Currents similar to those of the hairs of the nettle
have been observed in a great multitude of very different plants, and
weighty authorities have suggested that they probably occur, in more or
less perfection, in all young vegetable cells. If such be the case, the
wonderful noonday silence of a tropical forest is, after all, due only to
the dulness of our hearing; and could our ears catch the murmur of these
tiny Maelstroms, 96 as they whirl in the innumerable
myriads of living cells which constitute each tree, we should be stunned,
as with the roar of a great city.
Among the lower plants, it is the rule rather than the exception, that
contractility should be still more openly manifested at some periods of
their existence. The protoplasm of Algae and Fungi becomes, under many
circumstances, partially, or completely, freed from its woody case, and
exhibits movements of its whole mass, or is propelled by the contractility
of one, or more, hair-like prolongations of its body, which are called
vibratile cilia. And, so far as the conditions of the manifestation of the
phaenomena of contractility have yet been studied, they are the same for
the plant as for the animal. Heat and electric shocks influence both, and
in the same way, though it may be in different degrees. It is by no means
my intention to suggest that there is no difference in faculty between the
lowest plant and the highest, or between plants and animals. But the
difference between the powers of the lowest plant, or animal, and those of
the highest, is one of degree, not of kind, and depends, as Milne-Edwards
97
long ago so well pointed out, upon the extent to which the principle of
the division of labour is carried out in the living economy. In the lowest
organism all parts are competent to perform all functions, and one and the
same portion of protoplasm may successfully take on the function of
feeding, moving, or reproducing apparatus. In the highest, on the
contrary, a great number of parts combine to perform each function, each
part doing its allotted share of the work with great accuracy and
efficiency, but being useless for any other purpose.
On the other hand, notwithstanding all the fundamental resemblances which
exist between the powers of the protoplasm in plants and in animals, they
present a striking difference (to which I shall advert more at length
presently), in the fact that plants can manufacture fresh protoplasm out
of mineral compounds, whereas animals are obliged to procure it ready
made, and hence, in the long run, depend upon plants. Upon what condition
this difference in the powers of the two great divisions of the world of
life depends, nothing is at present known.
With such qualifications as arises 98 out of the
last-mentioned fact, it may be truly said that the acts of all living
things are fundamentally one. Is any such unity predicable of their forms?
Let us seek in easily verified facts for a reply to this question. If a
drop of blood be drawn by pricking one's finger, and viewed with proper
precautions, and under a sufficiently high microscopic power, there will
be seen, among the innumerable multitude of little, circular, discoidal
bodies, or corpuscles, which float in it and give it its colour, a
comparatively small number of colourless corpuscles, of somewhat larger
size and very irregular shape. If the drop of blood be kept at the
temperature of the body, these colourless corpuscles will be seen to
exhibit a marvellous activity, changing their forms with great rapidity,
drawing in and thrusting out prolongations of their substance, and
creeping about as if they were independent organisms.
The substance which is thus active is a mass of protoplasm, and its
activity differs in detail, rather than in principle, from that of the
protoplasm of the nettle. Under sundry circumstances the corpuscle dies
and becomes distended into a round mass, in the midst of which is seen a
smaller spherical body, which existed, but was more or less hidden, in the
living corpuscle, and is called its nucleus. Corpuscles of essentially
similar structure are to be found in the skin, in the lining of the mouth,
and scattered through the whole framework of the body. Nay, more; in the
earliest condition of the human organism, in that state in which it has
but just become distinguishable from the egg in which it arises, it is
nothing but an aggregation of such corpuscles, and every organ of the body
was, once, no more than such an aggregation.
Thus a nucleated mass of protoplasm turns out to be what may be termed the
structural unit of the human body. As a matter of fact, the body, in its
earliest state, is a mere multiple of such units; and in its perfect
condition, it is a multiple of such units, variously modified.
But does the formula which expresses the essential structural character of
the highest animal cover all the rest, as the statement of its powers and
faculties covered that of all others? Very nearly. Beast and fowl, reptile
and fish, mollusk, worm, and polype, are all composed of structural units
of the same character, namely, masses of protoplasm with a nucleus. There
are sundry very low animals, each of which, structurally, is a mere
colourless blood-corpuscle, leading an independent life. But, at the very
bottom of the animal scale, even this simplicity becomes simplified, and
all the phaenomena of life are manifested by a particle of protoplasm
without a nucleus. Nor are such organisms insignificant by reason of their
want of complexity. It is a fair question whether the protoplasm of those
simplest forms of life, which people an immense extent of the bottom of
the sea, would not outweigh that of all the higher living beings which
inhabit the land put together. And in ancient times, no less than at the
present day, such living beings as these have been the greatest of rock
builders.
What has been said of the animal world is no less true of plants. Imbedded
in the protoplasm at the broad, or attached, end of the nettle hair, there
lies a spheroidal nucleus. Careful examination further proves that the
whole substance of the nettle is made up of a repetition of such masses of
nucleated protoplasm, each contained in a wooden case, which is modified
in form, sometimes into a woody fibre, sometimes into a duct or spiral
vessel, sometimes into a pollen grain, or an ovule. Traced back to its
earliest state, the nettle arises as the man does, in a particle of
nucleated protoplasm. And in the lowest plants, as in the lowest animals,
a single mass of such protoplasm may constitute the whole plant, or the
protoplasm may exist without a nucleus.
Under these circumstances it may well be asked, how is one mass of
non-nucleated protoplasm to be distinguished from another? why call one
"plant" and the other "animal"?
The only reply is that, so far as form is concerned, plants and animals
are not separable, and that, in many cases, it is a mere matter of
convention whether we call a given organism an animal or a plant. There is
a living body called Aethalium septicum, which appears upon decaying
vegetable substances, and, in one of its forms, is common upon the
surfaces of tan-pits. In this condition it is, to all intents and
purposes, a fungus, and formerly was always regarded as such; but the
remarkable investigations of De Bary 99 have shown
that, in another condition, the Aethalium is an actively locomotive
creature, and takes in solid matters, upon which, apparently, it feeds,
thus exhibiting the most characteristic feature of animality. Is this a
plant; or is it an animal? Is it both; or is it neither? Some decide in
favour of the last supposition, and establish an intermediate kingdom, a
sort of biological No Man's Land 100 for all
these questionable forms. But, as it is admittedly impossible to draw any
distinct boundary line between this no man's land and the vegetable world
on the one hand, or the animal, on the other, it appears to me that this
proceeding merely doubles the difficulty which, before, was single.
Protoplasm, simple or nucleated, is the formal basis of all life. It is
the clay of the potter: which, bake it and paint it as he will, remains
clay, separated by artifice, and not by nature, from the commonest brick
or sun-dried clod.
Thus it becomes clear that all living powers are cognate, and that all
living forms are fundamentally of one character. The researches of the
chemist have revealed a no less striking uniformity of material
composition in living matter.
In perfect strictness, it is true that chemical investigation can tell us
little or nothing, directly, of the composition of living matter, inasmuch
as such matter must needs die in the act of analysis,—and upon this
very obvious ground, objections, which I confess seem to me to be somewhat
frivolous, have been raised to the drawing of any conclusions whatever
respecting the composition of actually living matter, from that of the
dead matter of life, which alone is accessible to us. But objectors of
this class do not seem to reflect that it is also, in strictness, true
that we know nothing about the composition of any body whatever, as it is.
The statement that a crystal of calc-spar consists of carbonate of lime,
is quite true, if we only mean that, by appropriate processes, it may be
resolved into carbonic acid and quicklime. If you pass the same carbonic
acid over the very quicklime thus obtained, you will obtain carbonate of
lime again; but it will not be calc-spar, nor anything like it. Can it,
therefore, be said that chemical analysis teaches nothing about the
chemical composition of calc-spar? Such a statement would be absurd; but
it is hardly more so than the talk one occasionally hears about the
uselessness of applying the results of chemical analysis to the living
bodies which have yielded them.
One fact, at any rate, is out of reach of such refinements, and this is,
that all the forms of protoplasm which have yet been examined contain the
four elements, carbon, hydrogen, oxygen, and nitrogen, in very complex
union, and that they behave similarly towards several reagents. To this
complex combination, the nature of which has never been determined with
exactness, the name of Protein has been applied. And if we use this term
with such caution as may properly arise out of our comparative ignorance
of the things for which it stands, it may be truly said, that all
protoplasm is proteinaceous, or, as the white, or albumen, of an egg is
one of the commonest examples of a nearly pure proteine matter, we may say
that all living matter is more or less albuminoid.
Perhaps it would not yet be safe to say that all forms of protoplasm are
affected by the direct action of electric shocks; and yet the number of
cases in which the contraction of protoplasm is shown to be affected by
this agency increases every day.
Nor can it be affirmed with perfect confidence, that all forms of
protoplasm are liable to undergo that peculiar coagulation at a
temperature of 40-50 degrees centigrade, which has been called
"heat-stiffening," though Kuhne's 101
beautiful researches have proved this occurrence to take place in so many
and such diverse living beings, that it is hardly rash to expect that the
law holds good for all.
Enough has, perhaps, been said to prove the existence of a general
uniformity in the character of the protoplasm, or physical basis, of life,
in whatever group of living beings it may be studied. But it will be
understood that this general uniformity by no means excludes any amount of
special modifications of the fundamental substance. The mineral, carbonate
of lime, assumes an immense diversity of characters, though no one doubts
that, under all these Protean changes, it is one and the same thing.
And now, what is the ultimate fate, and what the origin, of the matter of
life?
Is it, as some of the older naturalists supposed, diffused throughout the
universe in molecules, which are indestructible and unchangeable in
themselves; but, in endless transmigration, unite in innumerable
permutations, into the diversified forms of life we know? Or, is the
matter of life composed of ordinary matter, differing from it only in the
manner in which its atoms are aggregated? Is it built up of ordinary
matter, and again resolved into ordinary matter when its work is done?
Modern science does not hesitate a moment between these alternatives.
Physiology writes over the portals of life—
"Debemur morti nos nostraque,"102
with a profounder meaning than the Roman poet attached to that melancholy
line. Under whatever disguise it takes refuge, whether fungus or oak, worm
or man, the living protoplasm not only ultimately dies and is resolved
into its mineral and lifeless constituents, but is always dying, and,
strange as the paradox may sound, could not live unless it died.
In the wonderful story of the Peau de Chagrin,103 the
hero becomes possessed of a magical wild ass' skin, which yields him the
means of gratifying all his wishes. But its surface represents the
duration of the proprietor's life; and for every satisfied desire the skin
shrinks in proportion to the intensity of fruition, until at length life
and the last handbreadth of the peau de chagrin, disappear with the
gratification of a last wish.
Balzac's 104 studies had led him over a
wide range of thought and speculation, and his shadowing forth of
physiological truth in this strange story may have been intentional. At
any rate, the matter of life is a veritable peau de chagrin, and for every
vital act it is somewhat the smaller. All work implies waste, and the work
of life results, directly or indirectly, in the waste of protoplasm.
Every word uttered by a speaker costs him some physical loss; and, in the
strictest sense, he burns that others may have light—so much
eloquence, so much of his body resolved into carbonic acid, water, and
urea. It is clear that this process of expenditure cannot go on for ever.
But, happily, the protoplasmic peau de chagrin differs from Balzac's in
its capacity of being repaired, and brought back to its full size, after
every exertion.
For example, this present lecture, whatever its intellectual worth to you,
has a certain physical value to me, which is, conceivably, expressible by
the number of grains of protoplasm and other bodily substance wasted in
maintaining my vital processes during its delivery. My peau de chagrin
will be distinctly smaller at the end of the discourse than it was at the
beginning. By and by, I shall probably have recourse to the substance
commonly called mutton, for the purpose of stretching it back to its
original size. Now this mutton was once the living protoplasm, more or
less modified, of another animal—a sheep. As I shall eat it, it is
the same matter altered, not only by death, but by exposure to sundry
artificial operations in the process of cooking.
But these changes, whatever be their extent, have not rendered it
incompetent to resume its old functions as matter of life. A singular
inward laboratory, which I possess, will dissolve a certain portion of the
modified protoplasm; the solution so formed will pass into my veins; and
the subtle influences to which it will then be subjected will convert the
dead protoplasm into living protoplasm, and transubstantiate sheep into
man.
Nor is this all. If digestion were a thing to be trifled with, I might sup
upon lobster, and the matter of life of the crustacean would undergo the
same wonderful metamorphosis into humanity. And were I to return to my own
place by sea, and undergo shipwreck, the crustacean might, and probably
would, return the compliment, and demonstrate our common nature by turning
my protoplasm into living lobster. Or, if nothing better were to be had, I
might supply my wants with mere bread, and I should find the protoplasm of
the wheat-plant to be convertible into man, with no more trouble than that
of the sheep, and with far less, I fancy, than that of the lobster.
Hence it appears to be a matter of no great moment what animal, or what
plant, I lay under contribution for protoplasm, and the fact speaks
volumes for the general identity of that substance in all living beings. I
share this catholicity of assimilation with other animals, all of which,
so far as we know, could thrive equally well on the protoplasm of any of
their fellows, or of any plant; but here the assimilative powers of the
animal world cease. A solution of smelling-salts in water, with an
infinitesimal proportion of some other saline matters, contains all the
elementary bodies which enter into the composition of protoplasm; but, as
I need hardly say, a hogshead of that fluid would not keep a hungry man
from starving, nor would it save any animal whatever from a like fate. An
animal cannot make protoplasm, but must take it ready-made from some other
animal, or some plant—the animal's highest feat of constructive
chemistry being to convert dead protoplasm into that living matter of life
which is appropriate to itself.
Therefore, in seeking for the origin of protoplasm, we must eventually
turn to the vegetable world. A fluid containing carbonic acid, water, and
nitrogenous salts, which offers such a Barmecide feast 105
to the animal, is a table richly spread to multitudes of plants; and, with
a due supply of only such materials, many a plant will not only maintain
itself in vigour, but grow and multiply until it has increased a
million-fold, or a million million-fold, the quantity of protoplasm which
it originally possessed; in this way building up the matter of life, to an
indefinite extent, from the common matter of the universe.
Thus, the animal can only raise the complex substance of dead protoplasm
to the higher power, as one may say, of living protoplasm; while the plant
can raise the less complex substances—carbonic acid, water, and
nitrogenous salts—to the same stage of living protoplasm, if not to
the same level. But the plant also has its limitations. Some of the fungi,
for example, appear to need higher compounds to start with; and no known
plant can live upon the uncompounded elements of protoplasm. A plant
supplied with pure carbon, hydrogen, oxygen, and nitrogen, phosphorus,
sulphur, and the like, would as infallibly die as the animal in his bath
of smelling-salts, though it would be surrounded by all the constituents
of protoplasm. Nor, indeed, need the process of simplification of
vegetable food be carried so far as this, in order to arrive at the limit
of the plant's thaumaturgy. Let water, carbonic acid, and all the other
needful constituents be supplied except nitrogenous salts, and an ordinary
plant will still be unable to manufacture protoplasm.
Thus the matter of life, so far as we know it (and we have no right to
speculate on any other), breaks up, in consequence of that continual death
which is the condition of its manifesting vitality, into carbonic acid,
water, and nitrogenous compounds, which certainly possess no properties
but those of ordinary matter. And out of these same forms of ordinary
matter, and from none which are simpler, the vegetable world builds up all
the protoplasm which keeps the animal world a-going. Plants are the
accumulators of the power which animals distribute and disperse.
But it will be observed, that the existence of the matter of life depends
on the pre-existence of certain compounds; namely, carbonic acid, water,
and certain nitrogenous bodies. Withdraw any one of these three from the
world, and all vital phaenomena come to an end. They are as necessary to
the protoplasm of the plant, as the protoplasm of the plant is to that of
the animal. Carbon, hydrogen, oxygen, and nitrogen are all lifeless
bodies. Of these, carbon and oxygen unite in certain proportions and under
certain conditions, to give rise to carbonic acid; hydrogen and oxygen
produce water; nitrogen and other elements give rise to nitrogenous salts.
These new compounds, like the elementary bodies of which they are
composed, are lifeless. But when they are brought together, under certain
conditions, they give rise to the still more complex body, protoplasm, and
this protoplasm exhibits the phaenomena of life.
I see no break in this series of steps in molecular complication, and I am
unable to understand why the language which is applicable to any one term
of the series may not be used to any of the others. We think fit to call
different kinds of matter carbon, oxygen, hydrogen, and nitrogen, and to
speak of the various powers and activities of these substances as the
properties of the matter of which they are composed.
When hydrogen and oxygen are mixed in a certain proportion, and an
electric spark is passed through them, they disappear, and a quantity of
water, equal in weight to the sum of their weights, appears in their
place. There is not the slightest parity between the passive and active
powers of the water and those of the oxygen and hydrogen which have given
rise to it. At 32 degrees Fahrenheit, and far below that temperature,
oxygen and hydrogen are elastic gaseous bodies, whose particles tend to
rush away from one another with great force. Water, at the same
temperature, is a strong though brittle solid whose particles tend to
cohere into definite geometrical shapes, and sometimes build up frosty
imitations of the most complex forms of vegetable foliage.
Nevertheless we call these, and many other strange phaenomena, the
properties of the water, and we do not hesitate to believe that, in some
way or another, they result from the properties of the component elements
of the water. We do not assume that a something called "aquosity" entered
into and took possession of the oxidated hydrogen as soon as it was
formed, and then guided the aqueous particles to their places in the
facets of the crystal, or amongst the leaflets of the hoar-frost. On the
contrary, we live in the hope and in the faith that, by the advance of
molecular physics, we shall by and by be able to see our way as clearly
from the constituents of water to the properties of water, as we are now
able to deduce the operations of a watch from the form of its parts and
the manner in which they are put together.
Is the case in any way changed when carbonic acid, water, and nitrogenous
salts disappear, and in their place, under the influence of pre-existing
living protoplasm, an equivalent weight of the matter of life makes its
appearance?
It is true that there is no sort of parity between the properties of the
components and the properties of the resultant, but neither was there in
the case of the water. It is also true that what I have spoken of as the
influence of pre-existing living matter is something quite unintelligible;
but does anybody quite comprehend the modus operandi 106
of an electric spark, which traverses a mixture of oxygen and hydrogen?
What justification is there, then, for the assumption of the existence in
the living matter of a something which has no representative, or
correlative, in the not living matter which gave rise to it? What better
philosophical status has "vitality" than "aquosity"? And why should
"vitality" hope for a better fate than the other "itys" which have
disappeared since Martinus Scriblerus 107
accounted for the operation of the meat-jack 108 by its
inherent "meat-roasting quality," and scorned the "materialism" of those
who explained the turning of the spit by a certain mechanism worked by the
draught of the chimney.
If scientific language is to possess a definite and constant signification
whenever it is employed, it seems to me that we are logically bound to
apply to the protoplasm, or physical basis of life, the same conceptions
as those which are held to be legitimate elsewhere. If the phaenomena
exhibited by water are its properties, so are those presented by
protoplasm, living or dead, its properties.
If the properties of water may be properly said to result from the nature
and disposition of its component molecules, I can find no intelligible
ground for refusing to say that the properties of protoplasm result from
the nature and disposition of its molecules.
But I bid you beware that, in accepting these conclusions, you are placing
your feet on the first rung of a ladder which, in most people's
estimation, is the reverse of Jacob's, and leads to the antipodes of
heaven. It may seem a small thing to admit that the dull vital actions of
a fungus, or a foraminifer, are the properties of their protoplasm, and
are the direct results of the nature of the matter of which they are
composed. But if, as I have endeavoured to prove to you, their protoplasm
is essentially identical with, and most readily converted into, that of
any animal, I can discover no logical halting-place between the admission
that such is the case, and the further concession that all vital action
may, with equal propriety, be said to be the result of the molecular
forces of the protoplasm which displays it. And if so, it must be true, in
the same sense and to the same extent, that the thoughts to which I am now
giving utterance, and your thoughts regarding them, are the expression of
molecular changes in that matter of life which is the source of our other
vital phaenomena.109
