Chapter 5
After we have marveled over all these hidden things, and been impressed by the world within world of the material universe, do we get any nearer to the mystery of life? Can we see where the tremendous change from the non-living to the living takes place? Can we evoke life from the omnipotent ether, or see it arise in the whirling stream of atoms and electrons? Molecular science opens up to us a world where the infinitely little matches the infinitely great, where matter is dematerialized and answers to many of the conceptions of spirit; but does it bring us any nearer the origin of life? Is radio-active matter any nearer living matter than is the clod under foot? Are the darting electrons any more vital than the shooting-stars? Can a flash of radium emanations on a zinc-sulphide plate kindle the precious spark? It is probably just as possible to evoke vitality out of the clash of billiard-balls as out of the clash of atoms and electrons. This allusion to billiard-balls recalls to my mind a striking passage from Tyndall's famous Belfast Address which he puts in the mouth of Bishop Butler in his imaginary argument with Lucretius, and which shows how thoroughly Tyndall appreciated the difficulties of his own position in advocating the theory of the physico-chemical origin of life.
The atomic and electronic theory of matter admits one to a world that does indeed seem unreal and fantastic. "If my bark sinks," says the poet, "'t is to another sea." If the mind breaks through what we call gross matter, and explores its interior, it finds itself indeed in a vast under or hidden world--a world almost as much a creation of the imagination as that visited by Alice in Wonderland, except that the existence of this world is capable of demonstration. It is a world of the infinitely little which science interprets in terms of the infinitely large. Sir Oliver Lodge sees the molecular spaces that separate the particles of any material body relatively like the interstellar spaces that separate the heavenly bodies. Just as all the so-called solid matter revealed by our astronomy is almost infinitesimal compared with the space through which it is distributed, so the electrons which compose the matter with which we deal are comparable to the bodies of the solar system moving in vast spaces. It is indeed a fantastic world where science conceives of bodies a thousand times smaller than the hydrogen atom--the smallest body known to science; where it conceives of vibrations in the ether millions of millions times a second; where we are bombarded by a shower of corpuscles from a burning candle, or a gas-jet, or a red-hot iron surface, moving at the speed of one hundred thousand miles a second! But this almost omnipotent ether has, after all, some of the limitations of the finite. It takes time to transmit the waves of light from the sun and the stars. This measurable speed, says Sir Oliver Lodge, gives the ether away, and shows its finite character.
It seems as if the theory of the ether must be true, because it fits in so well with the enigmatic, contradictory, incomprehensible character of the universe as revealed to our minds. We can affirm and deny almost anything of the ether--that it is immaterial, and yet the source of all material; that it is absolutely motionless, yet the cause of all motion; that it is the densest body in nature, and yet the most rarified; that it is everywhere, but defies detection; that it is as undiscoverable as the Infinite itself; that our physics cannot prove it, though they cannot get along without it. The ether inside a mass of iron or of lead is just as dense as the ether outside of it--which means that it is not dense at all, in our ordinary use of the term.
VI
There are physical changes in matter, there are chemical changes, and there is a third change, as unlike either of these as they are unlike each other. I refer to atomic change, as in radio-activity, which gives us lead from helium--a spontaneous change of the atoms. The energy that keeps the earth going, says Soddy, is to be sought for in the individual atoms; not in the great heaven-shaking voice of thunder, but in the still small voice of the atoms. Radio-activity is the mainspring of the universe. The only elements so far known that undergo spontaneous change are uranium and thorium. One pound of uranium contains and slowly gives out the same amount of energy that a hundred tons of coal evolves in its combustion, but only one ten-billionth part of this amount is given out every year.
Man, of course, reaps where he has not sown. How could it be otherwise? It takes energy to sow or plant energy. We are exhausting the coal, the natural gas, the petroleum of the rocks, the fertility of the soil. But we cannot exhaust the energy of the winds or the tides, or of falling water, because this energy is ever renewed by gravity and the sun. There can be no exhaustion of our natural mechanical and chemical resources, as some seem to fear.
I recently visited a noted waterfall in the South where electric power is being developed on a large scale. A great column of water makes a vertical fall of six hundred feet through a steel tube, and in the fall develops two hundred and fifty thousand horse-power. The water comes out of the tunnel at the bottom, precisely the same water that went in at the top; no change whatever has occurred in it, yet a vast amount of power has been taken out of it, or, rather, generated by its fall. Another drop of six hundred feet would develop as much more; in fact, the process may be repeated indefinitely, the same amount of power resulting each time, without effecting any change in the character of the water. The pull of gravity is the source of the power which is distributed hundreds of miles across the country as electricity. Two hundred and fifty thousand invisible, immaterial, noiseless horses are streaming along these wires with incredible speed to do the work of men and horses in widely separated parts of the country. A river of sand falling down those tubes, if its particles moved among themselves with the same freedom that those of the water do, would develop the same power. The attraction of gravitation is not supposed to be electricity, and yet here out of its pull upon the water comes this enormous voltage! The fact that such a mysterious and ubiquitous power as electricity can be developed from the action of matter without any alteration in its particles, suggests the question whether or not this something that we call life, or life-force, may not slumber in matter in the same way; but the secret of its development we have not yet learned, as we have that of electricity.
Radio-activity is uninfluenced by external conditions; hence we are thus far unable to control it. Nothing that is known will effect the transmutation of one element into another. It is spontaneous and uncontrollable. May not life be spontaneous in the same sense?
The release of the energy associated with the structure of the atoms is not available by any of our mechanical appliances. The process of radio-activity involves the expulsion of atoms of helium with a velocity three hundred times greater than that ever previously known for any material mass or particle, and this power we are incompetent to use. The atoms remain unchanged amid the heat and pressure of the laboratory of nature. Iron and oxygen and so forth remain the same in the sun as here on the earth.
Science strips gross matter of its grossness. When it is done with it, it is no longer the obstructive something we know and handle; it is reduced to pure energy--the line between it and spirit does not exist. We have found that bodies are opaque only to certain rays; the X-ray sees through this too too solid flesh. Bodies are ponderable only to our dull senses; to a finer hand than this the door or the wall might offer no obstruction; a finer eye than this might see the emanations from the living body; a finer ear might hear the clash of electrons in the air. Who can doubt, in view of what we already know, that forces and influences from out the heavens above, and from the earth beneath, that are beyond our ken, play upon us constantly?
The final mystery of life is no doubt involved in conditions and forces that are quite outside of or beyond our conscious life activities, in forces that play about us and upon and through us, that we know not of, because a knowledge of them is not necessary to our well-being. "Our eye takes in only an octave of the vibrations we call light," because no more is necessary for our action or our dealing with things. The invisible rays of the spectrum are potent, but they are beyond the ken of our senses. There are sounds or sound vibrations that we do not hear; our sense of touch cannot recognize a gossamer, or the gentler air movements.
I began with the contemplation of the beauty and terror of the thunderbolt--"God's autograph," as one of our poets (Joel Benton) said, "written upon the sky." Let me end with an allusion to another aspect of the storm that has no terror in it--the bow in the clouds: a sudden apparition, a cosmic phenomenon no less wonderful and startling than the lightning's flash. The storm with terror and threatened destruction on one side of it, and peace and promise on the other! The bow appears like a miracle, but it is a commonplace of nature; unstable as life, and beautiful as youth. The raindrops are not changed, the light is not changed, the laws of the storms are not changed; and yet, behold this wonder!
But all these strange and beautiful phenomena springing up in a world of inert matter are but faint symbols of the mystery and the miracle of the change of matter from the non-living to the living, from the elements in the clod to the same elements in the brain and heart of man.
IV
THE BAFFLING PROBLEM
I
Still the problem of living things haunts my mind and, let me warn my reader, will continue to haunt it throughout the greater part of this volume. The final truth about it refuses to be spoken. Every effort to do so but gives one new evidence of how insoluble the problem is.
In this world of change is there any other change to be compared with that in matter, from the dead to the living?--a change so great that most minds feel compelled to go outside of matter and invoke some super-material force or agent to account for it. The least of living things is so wonderful, the phenomena it exhibits are so fundamentally unlike those of inert matter, that we invent a word for it, _vitality_; and having got the word, we conceive of a vital force or principle to explain vital phenomena. Hence vitalism--a philosophy of living things, more or less current in the world from Aristotle's time down to our own. It conceives of something in nature super-mechanical and super-chemical, though inseparably bound up with these things. There is no life without material and chemical forces, but material and chemical forces do not hold the secret of life. This is vitalism as opposed to mechanism, or scientific materialism, which is the doctrine of the all-sufficiency of the physical forces operating in the inorganic world to give rise to all the phenomena of the organic world--a doctrine coming more and more in vogue with the progress of physical science. Without holding to any belief in the supernatural or the teleological, and while adhering to the idea that there has been, and can be, no break in the causal sequence in this world, may one still hold to some form of vitalism, and see in life something more than applied physics and chemistry?
Is biology to be interpreted in the same physical and chemical terms as geology? Are biophysics and geophysics one and the same? One may freely admit that there cannot be two kinds of physics, nor two kinds of chemistry--not one kind for a rock, and another kind for a tree, or a man. There are not two species of oxygen, nor two of carbon, nor two of hydrogen and nitrogen--one for living and one for dead matter. The water in the human body is precisely the same as the water that flows by in the creek or that comes down when it rains; and the sulphur and the lime and the iron and the phosphorus and the magnesium are identical, so far as chemical analysis can reveal, in the organic and the inorganic worlds. But are we not compelled to think of a kind of difference between a living and a non-living body that we cannot fit into any of the mechanical or chemical concepts that we apply to the latter? Professor Loeb, with his "Mechanistic Conception of Life"; Professor Henderson, of Harvard, with his "Fitness of the Environment"; Professor Le Dantec, of the Sorbonne in Paris, with his volume on "The Nature and Origin of Life," published a few years since; Professor Schäfer, President of the British Association, Professor Verworn of Bonn, and many others find in the laws and properties of matter itself a sufficient explanation of all the phenomena of life. They look upon the living body as only the sum of its physical and chemical activities; they do not seem to feel the need of accounting for life itself--for that something which confers vitality upon the heretofore non-vital elements. That there is new behavior, that there are new chemical compounds called organic,--tens of thousands of them not found in inorganic nature,--that there are new processes set up in aggregates of matter,--growth, assimilation, metabolism, reproduction, thought, emotion, science, civilization,--no one denies.
How are we going to get these things out of the old physics and chemistry without some new factor or agent or force? To help ourselves out here with a "vital principle," or with spirit, or a creative impulse, as Bergson does, seems to be the only course open to certain types of mind. Positive science cannot follow us in this step, because science is limited to the verifiable. The stream of forces with which it deals is continuous; it must find the physical equivalents of all the forces that go into the body in the output of the body, and it cannot admit of a life force which it cannot trace to the physical forces.
What has science done to clear up this mystery of vitality? Professor Loeb, our most eminent experimental biologist, has succeeded in fertilizing the eggs of some low forms of sea life by artificial means; and in one instance, at least, it is reported that the fatherless form grew to maturity. This is certainly an interesting fact, but takes us no nearer the solution of the mystery of vitality than the fact that certain chemical compounds may stimulate the organs of reproduction helps to clear up the mystery of generation; or the fact that certain other chemical compounds help the digestive and assimilative processes and further the metabolism of the body assists in clearing up the mystery that attaches to these things. In all such cases we have the living body to begin with. The egg of the sea-urchin and the egg of the jelly-fish are living beings that responded to certain chemical substances, so that a process is set going in their cell life that is equivalent to fertilization. It seems to me that the result of all Professor Loeb's valuable inquiries is only to give us a more intimate sense of how closely mechanical and chemical principles are associated and identified with all the phenomena of life and with all animal behavior. Given a living organism, mechanics and chemistry will then explain much of its behavior--practically all the behavior of the lower organisms, and much of that of the higher. Even when we reach man, our reactions to the environment and to circumstances play a great part in our lives; but dare we say that will, liberty of choice, ideation, do not play a part also? How much reality there is in the so-called animal will, is a problem; but that there is a foundation for our belief in the reality of the human will, I, for one, do not for a moment doubt. The discontinuity here is only apparent and not real. We meet with the same break when we try to get our mental states, our power of thought--a poem, a drama, a work of art, a great oration--out of the food we eat; but life does it, though our science is none the wiser for it. Our physical life forms a closed circle, science says, and what goes into our bodies as physical force, must come out in physical force, or as some of its equivalents. Well, one of the equivalents, transformed by some unknown chemism within us, is our psychic force, or states of consciousness. The two circles, the physical and the psychical, are not concentric, as Fiske fancied, but are linked in some mysterious way.
Professor Loeb is a master critic of the life processes; he and his compeers analyze them as they have never been analyzed before; but the solution of the great problem of life that we are awaiting does not come. A critic may resolve all of Shakespeare's plays into their historic and other elements, but that will not account for Shakespeare. Nature's synthesis furnishes occasions for our analysis. Most assuredly all psychic phenomena have a physical basis; we know the soul only through the body; but that they are all of physico-chemical origin, is another matter.
II
Biological science has hunted the secret of vitality like a detective; and it has done some famous work; but it has not yet unraveled the mystery. It knows well the part played by carbon, oxygen, and hydrogen in organic chemistry, that without water and carbon dioxide there could be no life; it knows the part played by light, air, heat, gravity, osmosis, chemical affinity, and all the hundreds or thousands of organic compounds; it knows the part played by what are called the enzymes, or ferments, in all living bodies, but it does not know the secret of these ferments; it knows the part played by colloids, or jelly-like compounds, that there is no living body without colloids, though there are colloid bodies that are not living; it knows the part played by oxidation, that without it a living body ceases to function, though everywhere all about us is oxidation without life; it knows the part played by chlorophyll in the vegetable kingdom, and yet how chlorophyll works such magic upon the sun's rays, using the solar energy to fix the carbon of carbonic acid in the air, and thereby storing this energy as it is stored in wood and coal and in much of the food we consume, is a mystery. Chemistry cannot repeat the process in its laboratories. The fungi do not possess this wonderful chlorophyllian power, and hence cannot use the sunbeam to snatch their carbon from the air; they must get it from decomposed vegetable matter; they feed, as the animals do, upon elements that have gone through the cycle of vegetable life. The secret of vegetable life, then, is in the green substance of the leaf where science is powerless to unlock it. Conjure with the elements as it may, it cannot produce the least speck of living matter. It can by synthesis produce many of the organic compounds, but only from matter that has already been through the organic cycle. It has lately produced rubber, but from other products of vegetable life.
As soon as the four principal elements, carbon, oxygen, hydrogen, and nitrogen, that make up the living body, have entered the world of living matter, their activities and possible combinations enormously increase; they enter into new relations with one another and form compounds of great variety and complexity, characterized by the instability which life requires. The organic compounds are vastly more sensitive to light and heat and air than are the same elements in the inorganic world. What has happened to them? Chemistry cannot tell us. Oxidation, which is only slow combustion, is the main source of energy in the body, as it is in the steam-engine. The storing of the solar energy, which occurs only in the vegetable, is by a process of reduction, that is, the separation of the carbon and oxygen in carbonic acid and water. The chemical reactions which liberate energy in the body are slow; in dead matter they are rapid and violent, or explosive and destructive. It is the chemistry in the leaf of the plant that diverts or draws the solar energy into the stream of life, and how it does it is a mystery.
The scientific explanations of life phenomena are all after the fact; they do not account for the fact; they start with the ready-made organism and then reduce its activities and processes to their physical equivalents. Vitality is given, and then the vital processes are fitted into mechanical and chemical concepts, or into moulds derived from inert matter--not a difficult thing to do, but no more an explanation of the mystery of vitality than a painting or a marble bust of Tyndall would be an explanation of that great scientist.
All Professor Loeb's experiments and criticisms throw light upon the life processes, or upon the factors that take part in them, but not upon the secret of the genesis of the processes themselves. Amid all the activities of his mechanical and chemical factors, there is ever present a factor which he ignores, which his analytical method cannot seize; namely, what Verworn calls "the specific energy of living substance." Without this, chemism and mechanism would work together to quite other ends. The water in the wave, and the laws that govern it, do not differ at all from the water and its laws that surround it; but unless one takes into account the force that makes the wave, an analysis of the phenomena will leave one where he began.
Professor Le Dantec leaves the subject where he took it up, with the origin of life and the life processes unaccounted for. His work is a description, and not an explanation. All our ideas about vitality, or an unknown factor in the organic world, he calls "mystic" and unscientific. A sharp line of demarcation between living and non-living bodies is not permissible. This, he says, is the anthropomorphic error which puts some mysterious quality or force in all bodies considered to be living. To Le Dantec, the difference between the quick and the dead is of the same order as the difference which exists between two chemical compounds--for example, as that which exists between alcohol and an aldehyde, a liquid that has two less atoms of hydrogen in its composition. Modify your chemistry a little, add or subtract an atom or two, more or less, of this or that gas, and dead matter thrills into life, or living matter sinks to the inert. In other words, life is the gift of chemistry, its particular essence is of the chemical order--a bold inference from the fact that there is no life without chemical reactions, no life without oxidation. Yet chemical reactions in the laboratory cannot produce life. With Le Dantec, biology, like geology and astronomy, is only applied mechanics and chemistry.
III
Such is the result of the rigidly objective study of life--the only method analytical science can pursue. The conception of vitality as a factor in itself answers to nothing that the objective study of life can disclose; such a study reveals a closed circle of physical forces, chemical and mechanical, into which no immaterial force or principle can find entrance. "The fact of being conscious," Le Dantec says with emphasis, "does not intervene in the slightest degree in directing vital movements." But common sense and everyday observation tell us that states of consciousness do influence the bodily processes--influence the circulation, the digestion, the secretions, the respiration.