The Breath of Life

by John Burroughs

Is gravity or chemical affinity any more real to the mind than vitality? Both are names for mysteries. Something which we call life lifts matter up, in opposition to gravity, into thousands of living forms. The tree lifts potash, silica, and lime up one or two hundred feet into the air; it elbows the soil away from its hole where it enters the ground; its roots split rocks. A giant sequoia lifts tons of solid matter and water up hundreds of feet. So will an explosion of powder or dynamite, but the tree does it slowly and silently by the organizing power of life. The vital is as inscrutably identified with the mechanical and chemical as the soul is identified with the body. They are one while yet they are two.

For purely mechanical things we can find equivalents. Arrest a purely mechanical process, and the machine only rests or rusts; arrest a vital process, and the machine evaporates, disintegrates, myriads of other machines reduce it to its original mineral and gaseous elements. In the organic world we strike a principle that is incalculable in its operation and incommensurable in its results. The physico-chemical forces we can bring to book; we know their orbits, their attractions and repulsions, and just what they will and will not do; we can forecast their movements and foresee their effects. But the vital forces transcend all our mathematics; we cannot anticipate their behavior. Start inert matter in motion and we know pretty nearly what will happen to it; mix the chemical elements together and we can foresee the results; but start processes or reactions we call life, and who can foresee the end? We know the sap will mount in the tree and the tree will be true to its type, but what do we or can we know of what it is that determines its kind and size? We know that in certain plants the leaves will always be opposite each other on the stalk, and that in other plants the leaves will alternate; that certain plants will have conspicuous and others inconspicuous flowers; but how can we know what it is in the cells of the plants that determines these things? We can graft the scion of a sour apple tree upon a sweet, and vice versa, and the fruit of the scion will be true to its kind, but no analysis of the scion or of the stock will reveal the secret, as it would in the case of chemical compounds. In inorganic nature we meet with concretions, but not secretions; with crystallization, but not with assimilation and growth from within. Chemistry tells us that the composition of animal bodies is identical with that of vegetable; that there is nothing in one that is not in the other; and yet, behold the difference! a difference beyond the reach of chemistry to explain. Biology can tell us all about these differences and many other things, but it cannot tell us the secret we are looking for,—what it is that fashions from the same elements two bodies so unlike as a tree and a man.

Decay and disintegration in the inorganic world often lead to the production of beautiful forms. In life the reverse is true; the vital forces build up varied and picturesque forms which when pulled down are shapeless and displeasing. The immense layers of sandstone and limestone out of which the wonderful forms that fill the Grand Cañon of the Colorado are carved were laid down in wide uniform sheets; if the waters had deposited their material in the forms which we now see, it would have been a miracle. We marvel and admire as we gaze upon them now; we do more, we have to speculate as to how it was all done by the blind, unintelligent forces. Giant stairways, enormous alcoves, dizzy, highly wrought balustrades, massive vertical walls standing four-square like huge foundations—how did all the unguided erosive forces do it? The secret is in the structure of the rock, in the lines of cleavage, in the unequal hardness, and in the impulsive, irregular, and unequal action of the eroding agents. These agents follow the lines of least resistance; they are active at different times and seasons, and from different directions; they work with infinite slowness; they undermine, they disintegrate, they dislodge, they transport; the hard streaks resist them, the soft streaks invite them; water charged with sand and gravel saws down; the wind, armed with fine sand, rounds off and hollows out; and thus the sculpturing goes on. But after you have reasoned out all these things, you still marvel at the symmetry and the structural beauty of the forms. They look like the handiwork of barbarian gods. They are the handiwork of physical forces which we can see and measure and in a degree control. But what a gulf separates them from the handiwork of the organic forces!

VI

Some things come and some things arise; things that already exist may come, but potential things arise; my friend comes to visit me, the tide comes up the river, the cold or hot wave comes from the west; but the seasons, night and morning, health and disease, and the like, do not come in this sense; they arise. Life does not come to dead matter in this sense; it arises. Day and night are not traveling round the earth, though we view them that way; they arise from the turning of the earth upon its axis. If we could keep up with the flying moments,—that is, with the revolution of the earth,—we could live always at sunrise, or sunset, or at noon, or at any other moment we cared to elect. Love or hate does not come to our hearts; it is born there; the breath does not come to the newborn infant; respiration arises there automatically. See how the life of the infant is involved in that first breath, yet it is not its life; the infant must first be alive before it can breathe. If it is still-born, the respiratory reaction does not take place. We can say, then, that the breath means life, and the life means breath; only we must say the latter first. We can say in the same way that organization means life, and life means organization. Something sets up the organizing process in matter. We may take all the physical elements of life known to us and jumble them together and shake them up to all eternity, and life will not result. A little friction between solid bodies begets heat, a little more and we get fire. But no amount of friction begets life. Heat and life go together, but heat is the secondary factor.

Life is always a vanishing-point, a constant becoming—an unstable something that escapes us while we seem to analyze it. In its nature or essence, it is a metaphysical problem, and not one of physical science. Science cannot grasp it; it evaporates in its crucibles. And science is compelled finally to drive it into an imaginary region—I had almost said, metaphysical region, the region of the invisible, hypothetical atoms of matter. Here in the mysteries of molecular attraction and repulsion, it conceives the secret of life to lie.

"Life is a wave," says Tyndall, but does not one conceive of something, some force or impulse in the wave that is not of the wave? What is it that travels along lifting new water each moment up into waves? It is a physical force communicated usually by the winds. When the wave dies upon the shore, this force is dissipated, not lost, or is turned into heat. Why may we not think of life as a vital force traveling through matter and lifting up into organic life waves in the same way? But not translatable into any other form of energy because not derivable from any other form.

Every species of animal has something about it that is unique and individual and that no chemical or physiological analysis of it will show—probably some mode of motion among its ultimate particles that is peculiar to itself. This prevents cross-breeding among different species and avoids a chaos of animal and vegetable forms. Living tissues and living organs from one species cannot be grafted upon the individuals of another species; the kidney of a cat, for instance, cannot be substituted for that of a dog, although the functions and the anatomy of the two are identical. It is suggested that an element of felineness and an element of canineness adhere in the cells of each, and the two are antagonistic. This specific quality, or selfness, of an animal pervades every drop of its blood, so that the blood relationship of the different forms may be thus tested, where chemistry is incompetent to show agreement or antagonism. The reactions of life are surer and more subtle than those of chemistry. Thus the blood relationship between birds and reptiles is clearly shown, as is the relationship of man and the chimpanzee and the orang-outang. The same general fact holds true in the vegetable world. You cannot graft the apple upon the oak, or the plum upon the elm. It seems as if there were the quality of oakness and the quality of appleness, and they would not mix.

The same thing holds among different chemical compounds. Substances which have precisely the same chemical formulæ (called isomers) have properties as widely apart as alcohol and ether.

If chemistry is powerless to trace the relationship between different forms of life, is it not highly improbable that the secret of life itself is in the keeping of chemistry?