The Breath of Life

by John Burroughs

Living bodies are immersed in physical conditions as in a sea. External agencies—light, moisture, air, gravity, mechanical and chemical influences—cause great changes in them; but their power to adapt themselves to these changes, and profit by them, remains unexplained. Are morphological processes identical with chemical ones?

In the inorganic world we everywhere see mechanical adjustment, repose, stability, equilibrium, through the action and interaction of outward physical forces; a natural bridge is a striking example of the action of blind mechanical forces among the rocks. In the organic world we see living adaptation which involves a non-mechanical principle. An adjustment is an outward fitting together of parts; an adaptation implies something flowing, unstable, plastic, compromising; it is a moulding process; passivity on one side, and activity on the other. Living things struggle; they struggle up as well as down; they struggle all round the circle, while the pull of dead matter is down only.

Behold what a good chemist a plant is! With what skill it analyzes the carbonic acid in the air, retaining the carbon and returning the oxygen to the atmosphere! Then the plant can do what no chemist has yet been able to do; it can manufacture chlorophyll, a substance which is the basis of all life on the globe. Without chlorophyll (the green substance in plants) the solar energy could not be stored up in the vegetable world. Chlorophyll makes the plant, and the plant makes chlorophyll. To ask which is first is to call up the old puzzle, Which is first, the egg, or the hen that laid it?

According to Professor Soddy, the engineer's unit of power, that of the British cart-horse, has to be multiplied many times in a machine before it can do the work of a horse. He says that a car which two horses used to pull, it now takes twelve or fifteen engine-horse to pull. The machine horse belongs to a different order. He does not respond to the whip; he has no nervous system; he has none of the mysterious reserve power which a machine built up of living cells seems to possess; he is inelastic, non-creative, non-adaptive; he cannot take advantage of the ground; his pull is a dead, unvarying pull. Living energy is elastic, adaptive, self-directive, and suffers little loss through friction, or through imperfect adjustment of the parts. A live body converts its fuel into energy at a low temperature. One of the great problems of the mechanics of the future is to develop electricity or power directly from fuel and thus cut out the enormous loss of eighty or ninety per cent which we now suffer. The growing body does this all the time; life possesses this secret; the solar energy stored up in fuel suffers no loss in being transformed into work by the animal mechanism.

Soddy asks whether or not the minute cells of the body may not have the power of taking advantage of the difference in temperature of the molecules bombarding them, and thus of utilizing energy that is beyond the capacity of the machinery of the motor-car. Man can make no machine that can avail itself of the stores of energy in the uniform temperature of the earth or air or water, or that can draw upon the potential energy of the atoms, but it may be that the living cell can do this, and thus a horse can pull more than a one-horse-power engine. Soddy makes the suggestive inquiry: "If life begins in a single cell, does intelligence? does the physical distinction between living and dead matter begin in the jostling molecular crowd? Inanimate molecules, in all their movements, obey the law of probability, the law which governs the successive falls of a true die. In the presence of a rudimentary intelligence, do they still follow that law, or do they now obey another law—the law of a die that is loaded?" In a machine the energy of fuel has first to be converted into heat before it is available, but in a living machine the chemical energy of food undergoes direct transformation into work, and the wasteful heat-process is cut off.

VI

Professor Soddy, in discussing the relation of life to energy, does not commit himself to the theory of the vitalistic or non-mechanical origin of life, but makes the significant statement that there is a consensus of opinion that the life processes are not bound by the second law of thermo-dynamics, namely, the law of the non-availability of the energy latent in low temperatures, or in the chaotic movements of molecules everywhere around us. To get energy, one must have a fall or an incline of some sort, as of water from a higher to a lower level, or of temperature from a higher to a lower degree, or of electricity from one condition of high stress to another less so. But the living machine seems able to dispense with this break or incline, or else has the secret of creating one for itself.

In the living body the chemical energy of food is directly transformed into work, without first being converted into heat. Why a horse can do more work than a one-horse-power engine is probably because his living cells can and do draw upon this molecular energy. Molecules of matter outside the living body all obey the law of probability, or the law of chance; but inside the living body they at least seem to obey some other law—the law of design, or of dice that are loaded, as Soddy says. They are more likely always to act in a particular way. Life supplies a directing agency. Soddy asks if the physical distinction between living and dead matter begins in the jostling molecular crowd—begins by the crowd being directed and governed in a particular way. If so, by what? Ah! that is the question. Science will have none of it, because science would have to go outside of matter for such an agent, and that science cannot do. Such a theory implies intelligence apart from matter, or working in matter. Is that a hard proposition? Intelligence clearly works in our bodies and brains, and in those of all the animals—a controlled and directed activity in matter that seems to be life. The cell which builds up all living bodies behaves not like a machine, but like a living being; its activities, so far as we can judge, are spontaneous, its motions and all its other processes are self-prompted. But, of course, in it the mechanical, the chemical, and the vital are so blended, so interdependent, that we may never hope to separate them; but without the activity called vital, there would be no cell, and hence no body.

It were unreasonable to expect that scientific analysis should show that the physics and chemistry of a living body differs from that of the non-living. What is new and beyond the reach of science to explain is the kind of activity of these elements. They enter into new compounds; they build up bodies that have new powers and properties; they people the seas and the air and the earth with living creatures, they build the body and brain of man. The secret of the activity in matter that we call vital is certainly beyond the power of science to tell us. It is like expecting that the paint and oil used in a great picture must differ from those in a daub. The great artist mixed his paint with brains, and the universal elements in a living body are mixed with something that science cannot disclose. Organic chemistry does not differ intrinsically from inorganic; the difference between the two lies in the purposive activity of the elements that build up a living body.

Or is life, as a New England college professor claims, "an x-entity, additional to matter and energy, but of the same cosmic rank as they," and "manifesting itself to our senses only through its power to keep a certain quantity of matter and energy in the continuous orderly ferment we call life"?