Chapter 10 No.10

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 substitute 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.

And herein is one of the mysteries of chemistry again. This support which the oxygen gives is utterly unlike any support we are acquainted with in the world of mechanical forces. Oxygen supports combustion by combining chemically with carbon, and the evolution of heat and light is the result. And this is another mystery-this chemical union which takes place in the ultimate particles of matter and which is so radically different from a mechanical mixture. In a chemical union the atoms are not simply in juxtaposition; they are, so to speak, inside of one another-each has swallowed another and lost its identity, an impossible feat, surely, viewed in the light of our experiences with tangible bodies. In the visible, mechanical world no two bodies can occupy the same place at the same time, but apparently in chemistry they can and do. An atom of oxygen and one of carbon, or of hydrogen, unite and are lost in each other; it is a marriage wherein the two or three become one. In dealing with the molecules and atoms of matter we are in a world wherein the laws of solid bodies do not apply; friction is abolished, elasticity is perfect, and place and form play no part. We have escaped from matter as we know it, the solid, fluid, or gaseous forms, and are dealing with it in its fourth or ethereal estate. In breathing, the oxygen goes into the blood, not to stay there, but to unite with and bring away the waste of the system in the shape of carbon, and re-enter the air again as one of the elements of carbonic-acid gas, CO2. Then the reverse process takes place in the vegetable world, the leaves breathe this poisonous gas, release the oxygen under the chemistry of the sun's rays, and appropriate and store up the carbon. Thus do the animal and vegetable worlds play into each other's hands. The animal is dependent upon the vegetable for its carbon, which it releases again, through the life processes, as carbonic-acid gas, to be again drawn into the cycle of vegetable life.

The act of breathing well illustrates our mysterious relations to Nature-the cunning way in which she plays the principal part in our lives without our knowledge. How certain we are that we draw the air into our lungs-that we seize hold of it in some way as if it were a continuous substance, and pull it into our bodies! Are we not also certain that the pump sucks the water up through the pipe, and that we suck our iced drinks through a straw? We are quite unconscious of the fact that the weight of the superincumbent air does it all, that breathing is only to a very limited extent a voluntary act. It is controlled by muscular machinery, but that machinery would not act in a vacuum. We contract the diaphragm, or the diaphragm contracts under stimuli received through the medulla oblongata from those parts of the body which constantly demand oxygen, and a vacuum tends to form in the chest, which is constantly prevented by the air rushing in to fill it. The expansive force of the air under its own weight causes the lungs to fill, just as it causes the bellows of the blacksmith to fill when he works the lever, and the water to rise in the pump when we force out the air by working the handle. Another unconscious muscular effort under the influence of nerve stimulus, and the air is forced out of the lungs, charged with the bodily waste which it is the function to relieve. But the wonder of it all is how slight a part our wills play in the process, and how our lives are kept going by a mechanical force from without, seconded or supplemented by chemical and vital forces from within.

The one chemical process with which we are familiar all our lives, but which we never think of as such, is fire. Here on our own hearthstones goes on this wonderful spectacular and beneficent transformation of matter and energy, and yet we are grown so familiar with it that it moves us not. We can describe combustion in terms of chemistry, just as we can describe the life-processes in similar terms, yet the mystery is no more cleared up in the one case than in the other. Indeed, it seems to me that next to the mystery of life is the mystery of fire. The oxidizing processes are identical, only one is a building up or integrating process, and the other is a pulling down or disintegrating process. More than that, we can evoke fire any time, by both mechanical and chemical means, from the combustible matter about us; but we cannot evoke life. The equivalents of life do not slumber in our tools as do the equivalents of fire. Hence life is the deeper mystery. The ancients thought of a spirit of fire as they did of a spirit of health and of disease, and of good and bad spirits all about them, and as we think of a spirit of life, or of a creative life principle. Are we as wide of the mark as they were? So think many earnest students of living things. When we do not have to pass the torch of life along, but can kindle it in our laboratories, then this charge will assume a different aspect.