I have no doubt that Huxley was right in his inference "that if the properties of matter result from the nature and disposition of its component molecules, then there is no intelligible ground for refusing to say that the properties of protoplasm result from the nature and disposition of its molecules." It is undoubtedly in that nature and disposition of the biological molecules that Tyndall"s whole "mystery and miracle of vitality" is wrapped up. If we could only grasp what it is that transforms the molecule of dead matter into the living molecule!
Pasteur called it "dissymmetric force," which is only a new name for the mystery. He believed there was an "irrefragable physical barrier between organic and inorganic nature"--that the molecules of an organism differed from those of a mineral, and for this difference he found a name.
III
There seems to have been of late years a marked reaction, even among men of science, from the mechanistic conception of life as held by the band of scientists to which I have referred. Something like a new vitalism is making headway both on the Continent and in Great Britain. Its exponents urge that biological problems "defy any attempt at a mechanical explanation." These men stand for the idea "of the creative individuality of organisms" and that the main factors in organic evolution cannot be accounted for by the forces already operative in the inorganic world.
There is, of course, a mathematical chance that in the endless changes and permutations of inert matter the four princ.i.p.al elements that make up a living body may fall or run together in just that order and number that the kindling of the flame of life requires, but it is a disquieting proposition. One atom too much or too little of any of them,--three of oxygen where two were required, or two of nitrogen where only one was wanted,--and the face of the world might have been vastly different. Not only did much depend on their coming together, but upon the order of their coming; they must unite in just such an order. Insinuate an atom or corpuscle of hydrogen or carbon at the wrong point in the ranks, and the trick is a failure. Is there any chance that they will hit upon a combination of things and forces that will make a machine--a watch, a gun, or even a row of pins?
When we regard all the phenomena of life and the spell it seems to put upon inert matter, so that it behaves so differently from the same matter before it is drawn into the life circuit, when we see how it lifts up a world of dead particles out of the soil against gravity into trees and animals; how it changes the face of the earth; how it comes and goes while matter stays; how it defies chemistry and physics to evoke it from the non-living; how its departure, or cessation, lets the matter fall back to the inorganic--when we consider these and others like them, we seem compelled to think of life as something, some force or principle in itself, as M. Bergson and Sir Oliver Lodge do, existing apart from the matter it animates.
Sir Oliver Lodge, famous physicist that he is, yet has a vein of mysticism and idealism in him which sometimes makes him recoil from the hard-and-fast interpretations of natural phenomena by physical science.
Like M. Bergson, he sees in life some tendency or impetus which arose in matter at a definite time and place, "and which has continued to interact with and incarnate itself in matter ever since."
If a living body is a machine, then we behold a new kind of machine with new kinds of mechanical principles--a machine that repairs itself, that reproduces itself, a clock that winds itself up, an engine that stokes itself, a gun that aims itself, a machine that divides and makes two, two unite and make four, a million or more unite and make a man or a tree--a machine that is nine tenths water, a machine that feeds on other machines, a machine that grows stronger with use; in fact, a machine that does all sorts of unmechanical things and that no known combination of mechanical and chemical principles can reproduce--a vital machine.
The idea of the vital as something different from and opposed to the mechanical must come in. Something had to be added to the mechanical and chemical to make the vital.
Spencer explains in terms of physics why an ox is larger than the sheep, but he throws no light upon the subject of the individuality of these animals--what it is that makes an ox an ox or a sheep a sheep. These animals are built up out of the same elements by the same processes, and they may both have had the same stem form in remote biologic time. If so, what made them diverge and develop into such totally different forms? After the living body is once launched many, if not all, of its operations and economies can be explained on principles of mechanics and chemistry, but the something that avails itself of these principles and develops an ox in the one case and a sheep in the other--what of that?
Spencer is forced into using the terms "amount of vital capital." How much more of it some men, some animals, some plants have than others!
What is it? What did Spencer mean by it? This capital augments from youth to manhood, and then after a short or long state of equilibrium slowly declines to the vanishing-point.
Again, what a man does depends upon what he is, and what he is depends upon what he does. Structure determines function, and function reacts upon structure. This interaction goes on throughout life; cause and effect interchange or play into each other"s hands. The more power we spend within limits the more power we have. This is another respect in which life is utterly unmechanical. A machine does not grow stronger by use as our muscles do; it does not store up or conserve the energy it expends. The gun is weaker by every ball it hurls; not so the baseball pitcher; he is made stronger up to the limit of his capacity for strength.
It is plain enough that all living beings are machines in this respect--they are kept going by the reactions between their interior and their exterior; these reactions are either mechanical, as in flying, swimming, walking, and involve gravitation, or they are chemical and a.s.similative, as in breathing and eating. To that extent all living things are machines--some force exterior to themselves must aid in keeping them going; there is no spontaneous or uncaused movement in them; and yet what a difference between a machine and a living thing!
True it is that a man cannot live and function without heat and oxygen, nor long without food, and yet his relation to his medium and environment is as radically different from that of the steam-engine as it is possible to express. His driving-wheel, the heart, acts in response to some stimulus as truly as does the piston of the engine, and the principles involved in circulation are all mechanical; and yet the main thing is not mechanical, but vital. a.n.a.lyze the vital activities into principles of mechanics and of chemistry, if you will, yet there is something involved that is neither mechanical nor chemical, though it may be that only the imagination can grasp it.
The type that prints the book is set up and again distributed by a purely mechanical process, but that which the printed page signifies involves something not mechanical. The mechanical and chemical principles operative in men"s bodies are all the same; the cell structure is the same, and yet behold the difference between men in size, in strength, in appearance, in temperament, in disposition, in capacities! All the processes of respiration, circulation, and nutrition in our bodies involve well-known mechanical principles, and the body is accurately described as a machine; and yet if there were not something in it that transcends mechanics and chemistry would you and I be here? A machine is the same whether it is in action or repose, but when a body ceases to function, it is not the same. It cannot be set going like a machine; the motor power has ceased to be. But if the life of the body were no more than the sum of the reactions existing between the body and the medium in which it lives, this were not so. A body lives as long as there is a proper renewal of the interior medium through exchanges with its environment.
Mechanical principles are operative in every part of the body--in the heart, in the arteries, in the limbs, in the joints, in the bowels, in the muscles; and chemical principles are operative in the lungs, in the stomach, in the liver, in the kidneys; but to all these things do we not have to add something that is not mechanical or chemical to make the man, to make the plant? A higher mechanics, a higher chemistry, if you prefer, a force, but a force differing in kind from the physical forces.
The forces of life are constructive forces, and work in a world of disintegrating or destructive forces which oppose them and which they overcome. The mechanical and the chemical forces of dead matter are the enemies of the forces of life till life overcomes and uses them; as much so as gravity, fire, frost, water are man"s enemies till he has learned how to subdue and use them.
IV
It is a significant fact that the four chief elements which in various combinations make up living bodies are by their extreme mobility well suited to their purpose. Three of these are gaseous; only the carbon is a solid. This renders them facile and adaptive in the ever-changing conditions of organic evolution. The solid carbon forms the vessel in which the precious essence of life is carried. Without carbon we should evaporate or flow away and escape. Much of the oxygen and hydrogen enters into living bodies as water; nine tenths of the human body is water; a little nitrogen and a few mineral salts make up the rest. So that our life in its final elements is little more than a stream of water holding in solution carbonaceous and other matter and flowing, forever flowing, a stream of fluid and solid matter plus something else that scientific a.n.a.lysis cannot reach--some force or principle that combines and organizes these elements into the living body.
If a man could be reduced instantly into his const.i.tuent elements we should see a pail or two of turbid fluid that would flow down the bank and soon be lost in the soil. That which gives us our form and stability and prevents us from slowly spilling down the slope at all times is the mysterious vital principle or force which knits and marries these unstable elements together and raises up a mobile but more or less stable form out of the world of fluids. Venus rising from the sea is a symbol of the genesis of every living thing.
Inorganic matter seeks only rest. "Let me alone," it says; "do not break my slumbers." But as soon as life awakens in it, it says: "Give me room, get out of my way. Ceaseless activity, ceaseless change, a thousand new forms are what I crave." As soon as life enters matter, matter meets with a change of heart. It is lifted to another plane, the supermechanical plane; it behaves in a new way; its movements from being calculable become incalculable. A straight line has direction, that is mechanics; what direction has the circle? That is life, a change of direction every instant. An aeroplane is built entirely on mechanical principles, but something not so built has to sit in it and guide it; in fact, had to build it and adjust it to its end.
Mechanical forces seek an equilibrium or a state of rest. The whole inorganic world under the influence of gravity would flow as water flows, if it could, till it reached a state of absolute repose. But vital forces struggle against a state of repose, which to them means death. They are vital by virtue of their tendency to resist the repose of inert matter; chemical activity disintegrates a stone or other metal, but the decay of organized matter is different in kind; living organisms decompose it and resolve it into its original compounds.
Vital connections and mechanical connections differ in kind. You can treat mechanical principles mathematically, but can you treat life mathematically? Will your formulas and equations apply here? You can figure out the eclipses of the sun and moon for centuries to come, but who can figure out the eclipses of nations or the overthrow of parties or the failures of great men? And it is not simply because the problem is so vastly more complex; it is because you are in a world where mathematical principles do not apply. Mechanical forces will determine the place and shape of every particle of inert matter any number of years or centuries hence, but they will not determine the place and condition of matter imbued with the principle of life.
We can graft living matter, we can even graft a part of one animal"s body into another animal"s body, but the mechanical union which we bring about must be changed into vital union to be a success, the spirit of the body has to second our efforts. The same in grafting a tree or anything else: the mechanical union which we effect must become a vital union; and this will not take place without some degree of consanguinity, the live scion must be recognized and adapted by the stock in which we introduce it.
Living matter may be symbolized by a stream; it is ever and never the same; life is a constant becoming; our minds and our bodies are never the same at any two moments of time; life is ceaseless change.
No doubt it is between the stable and the unstable condition of the molecules of matter that life is born. The static condition to which all things tend is death. Matter in an unstable condition tends either to explode or to grow or to disintegrate. So that an explosion bears some a.n.a.logy to life, only it is quickly over and the static state of the elements is restored. Life is an infinitely slower explosion, or a prolonged explosion, during which some matter of the organism is being constantly burned up, and thus returned to a state of inorganic repose, while new matter is taken in and kindled and consumed by the fires of life. One can visualize all this and make it tangible to the intellect.
Get your fire of life started and all is easy, but how to start it is the rub. Get your explosive compound, and something must break the deadlock of the elements before it will explode. So in life, what is it that sets up this slow gentle explosion that makes the machinery of our vital economies go--that draws new matter into the vortex and casts the used-up material out--in short, that creates and keeps up the unstable condition, the seesaw upon which life depends? To enable the mind to grasp it we have to invent or posit some principle, call it the vital force, as so many have done and still do, or call it molecular force, as Tyndall does, or the power of G.o.d, as our orthodox brethren do, it matters not. We are on the border-land between the knowable and the unknowable, where the mind can take no further step. There is no life without carbon and oxygen, hydrogen and nitrogen, but there is a world of these elements without life. What must be added to them to set up the reaction we call life? Nothing that chemistry can disclose.
New tendencies and activities are set up among these elements, but the elements themselves are not changed; oxygen is still oxygen and carbon still carbon, yet behold the wonder of their new workmanship under the tutelage of life!
Life only appears when the stable pa.s.ses into the unstable, yet this change takes place all about us in our laboratories, and no life appears. We can send an electric spark through a room full of oxygen and hydrogen gas, and with a tremendous explosion we have water--an element of life, but not life.
Some of the elements seem nearer life than others. Water is near life; heat, light, the colloid state are near life; osmosis, oxidation, chemical reactions are near life; the ashes of inorganic bodies are nearer life than the same minerals in the rocks and soil; but none of these things is life.
The chemical mixture of some of the elements gives us our high explosives--gunpowder, guncotton, and the like; their organic mixture gives a slower kind of explosive--bread, meat, milk, fruit, which, when acted upon by the vital forces of the body, yield the force that is the equivalent of the work the body does. But to combine them in the laboratory so as to produce the compounds out of which the body can extract force is impossible. We can make an unstable compound that will hurl a ton of iron ten miles, but not one that when exploded in the digestive tract of the human body will lift a hair.
We may follow life down to the ground, yes, under the ground, into the very roots of matter and motion, yea, beyond the roots, into the imaginary world of molecules and atoms, and their attractions and repulsions and not find its secret. Indeed, science--the new science--pursues matter to the vanishing-point, where it ceases to become matter and becomes pure force or spirit. What takes place in that imaginary world where ponderable matter ends and becomes disembodied force, and where the hypothetical atoms are no longer divisible, we may conjecture but may never know. We may fancy the infinitely little going through a cycle of evolution like that of the infinitely great, and solar systems developing and revolving inside of the ultimate atoms, but the Copernicus or the Laplace of the atomic astronomy has not yet appeared. The atom itself is an invention of science. To get the mystery of vitality reduced to the atom is getting it in very close quarters, but it is a very big mystery still. Just how the dead becomes alive, even in the atom, is mystery enough to stagger any scientific mind. It is not the volume of the change; it is the quality or kind. Chemistry and mechanics we have always known, and they always remain chemistry and mechanics. They go into our laboratories and through our devices chemistry and mechanics, and they come out chemistry and mechanics. They will never come out life, conjure with them as we will, and we can get no other result. We cannot inaugurate the mystic dance among the atoms that will give us the least throb of life.
The psychic arises out of the organic and the organic arises out of the inorganic, and the inorganic arises out of--what? The relation of each to the other is as intimate as that of the soul to the body; we cannot get between them even in thought, but the difference is one of kind and not of degree. The vital transcends the mechanical, and the psychic transcends the vital--is on another plane, and yet without the sun"s energy there could be neither. Thus are things knit together; thus does one thing flow out of or bloom out of another. We date from the rocks, and the rocks date from the fiery nebulae, and the loom in which the texture of our lives was woven is the great loom of vital energy about us and in us; but what hand guided the shuttle and invented the pattern--who knows?
III
A WONDERFUL WORLD
I
Science recognizes a more fundamental world than that of matter. This is the electro-magnetic world which underlies the material world and which, as Professor Soddy says, probably completely embraces it, and has no mechanical a.n.a.logy. To those accustomed only to the grosser ideas of matter and its motions, says the British scientist, this electro-magnetic world is as difficult to conceive of as it would be for us to walk upon air. Yet many times in our lives is this world in overwhelming evidence before us. During a thunderstorm we get an inkling of how fearfully and wonderfully the universe in which we live is made, and what energy and activity its apparent pa.s.sivity and opacity mark. A flash of lightning out of a storm-cloud seems instantly to transform the whole pa.s.sive universe into a terrible living power. This slow, opaque, indifferent matter about us and above us, going its silent or noisy round of mechanical and chemical change, ponderable, insensate, obstructive, slumbering in the rocks, quietly active in the soil, gently rustling in the trees, sweetly purling in the brooks, slowly, invisibly building and shaping our bodies--how could we ever dream that it held in leash such a terrible, ubiquitous, spectacular thing as this of the forked lightning? If we were to see and hear it for the first time, should we not think that the Judgment Day had really come? that the great seals of the Book of Fate were being broken?
What an awakening it is! what a revelation! what a fearfully dramatic actor suddenly leaps upon the stage! Had we been permitted to look behind the scenes, we could not have found him; he was not there, except potentially; he was born and equipped in a twinkling. One stride, and one word which shakes the house, and he is gone; gone as quickly as he came. Look behind the curtain and he is not there. He has vanished more completely than any stage ghost ever vanished--he has withdrawn into the innermost recesses of the atomic structure of matter, and is diffused through the clouds, to be called back again, as the elemental drama proceeds, as suddenly as before.
All matter is charged with electricity, either actual or potential; the sun is hot with it, and doubtless our own heart-beats, our own thinking brains, are intimately related to it; yet it is palpable and visible only in this sudden and extraordinary way. It defies our a.n.a.lysis, it defies our definitions; it is inscrutable and incomprehensible, yet it will do our errands, light our houses, cook our dinners, and pull our loads.
How humdrum and constant and prosaic the other forces--gravity, cohesion, chemical affinity, and capillary attraction--seem when compared with this force of forces, electricity! How deep and prolonged it slumbers at one time, how terribly active and threatening at another, bellowing through the heavens like an infuriated G.o.d seeking whom he may destroy!
The warring of the elements at such times is no figure of speech. What has so disturbed the peace in the electric equilibrium, as to make possible this sudden outburst, this steep incline in the stream of energy, this ethereal Niagara pouring from heaven to earth? Is a thunderstorm a display of the atomic energy of which the physicists speak, and which, were it available for our use, would do all the work of the world many times over?
How marvelous that the softest summer breeze, or the impalpable currents of the calmest day, can be torn asunder with such suddenness and violence, by the acc.u.mulated energy that slumbers in the imaginary atoms, as to give forth a sound like the rending of mountains or the detonations of earthquakes!
Electricity is the soul of matter. If Whitman"s paradox is true, that the soul and body are one, in the same sense the scientific paradox is true: that matter and electricity are one, and both are doubtless a phase of the universal ether--a reality which can be described only in terms of the negation of matter. In a flash of lightning we see pure disembodied energy--probably that which is the main-spring of the universe. Modern science is more and more inclined to find the explanation of all vital phenomena in electrical stress and change. We know that an electric current will bring about chemical changes otherwise impracticable. Nerve force, if not a form of electricity, is probably inseparable from it. Chemical changes equivalent to the combustion of fuel and the corresponding amount of available energy released have not yet been achieved outside of the living body without great loss. The living body makes a short cut from fuel to energy, and this avoids the wasteful process of the engine. What part electricity plays in this process is, of course, only conjectural.
II
Our daily lives go on for the most part in two worlds, the world of mechanical transposition and the world of chemical transformations, but we are usually conscious only of the former. This is the visible, palpable world of motion and change that rushes and roars around us in the winds, the storms, the floods, the moving and falling bodies, and the whole panorama of our material civilization; the latter is the world of silent, invisible, unsleeping, and all-potent chemical reactions that take place all about us and is confined to the atoms and molecules of matter, as the former is confined to its visible aggregates.
Mechanical forces and chemical affinities rule our physical lives, and indirectly our psychic lives as well. When we come into the world and draw our first breath, mechanics and chemistry start us on our career.
Breathing is a mechanical, or a mechanico-vital, act; the mechanical principle involved is the same as that involved in the working of a bellows, but the oxidation of the blood when the air enters the lungs is a chemical act, or a chemico-vital act. The air gives up a part of its oxygen, which goes into the arterial circulation, and its place is taken by carbonic-acid gas and watery vapor. The oxygen feeds and keeps going the flame of life, as literally as it feeds and keeps going the fires in our stoves and furnaces.
Hence our most constant and vital relation to the world without is a chemical one. We can go without food for some days, but we can exist without breathing only a few moments. Through these spongy lungs of ours we lay hold upon the outward world in the most intimate and constant way. Through them we are rooted to the air. The air is a mechanical mixture of two very unlike gases--nitrogen and oxygen; one very inert, the other very active. Nitrogen is like a cold-blooded, lethargic person--it combines with other substances very reluctantly and with but little energy. Oxygen is just its opposite in this respect: it gives itself freely; it is "Hail, fellow; well met!" with most substances, and it enters into co-partnership with them on such a large scale that it forms nearly one half of the material of the earth"s crust. This invisible gas, this breath of air, through the magic of chemical combination, forms nearly half the substance of the solid rocks. Deprive it of its affinity for carbon, or subst.i.tute nitrogen or hydrogen in its place, and the air would quickly suffocate us. That changing of the dark venous blood in our lungs into the bright, red, arterial blood would instantly cease. Fancy the sensation of inhaling an odorless, non-poisonous atmosphere that would make one gasp for breath! We should be quickly poisoned by the waste of our own bodies. All things that live must have oxygen, and all things that burn must have oxygen. Oxygen does not burn, but it supports combustion.