Lives of a Cell Page 3
Gorillas beat their chests for certain kinds of discourse. Animals with loose skeletons rattle them, or, like rattle-snakes, get sounds from externally placed structures. Turtles, alligators, crocodiles, and even snakes make various more or less vocal sounds. Leeches have been heard to tap rhythmically on leaves, engaging the attention of other leeches, which tap back, in synchrony. Even earthworms make sounds, faint staccato notes in regular clusters. Toads sing to each other, and their friends sing back in antiphony.
Birdsong has been so much analyzed for its content of business communication that there seems little time left for music, but it is there. Behind the glossaries of warning calls, alarms, mating messages, pronouncements of territory, calls for recruitment, and demands for dispersal, there is redundant, elegant sound that is unaccountable as part of the working day. The thrush in my backyard sings down his nose in meditative, liquid runs of melody, over and over again, and I have the strongest impression that he does this for his own pleasure. Some of the time he seems to be practicing, like a virtuoso in his apartment. He starts a run, reaches a midpoint in the second bar where there should be a set of complex harmonics, stops, and goes back to begin over, dissatisfied. Sometimes he changes his notation so conspicuously that he seems to be improvising sets of variations. It is a meditative, questioning kind of music, and I cannot believe that he is simply saying, “thrush here.”
The robin sings flexible songs, containing a variety of motifs that he rearranges to his liking; the notes in each motif constitute the syntax, and the possibilities for variation produce a considerable repertoire. The meadow lark, with three hundred notes to work with, arranges these in phrases of three to six notes and elaborates fifty types of song. The nightingale has twenty-four basic songs, but gains wild variety by varying the internal arrangement of phrases and the length of pauses. The chaffinch listens to other chaffinches, and incorporates into his memory snatches of their songs.
The need to make music, and to listen to it, is universally expressed by human beings. I cannot imagine, even in our most primitive times, the emergence of talented painters to make cave paintings without there having been, near at hand, equally creative people making song. It is, like speech, a dominant aspect of human biology.
The individual parts played by other instrumentalists—crickets or earthworms, for instance—may not have the sound of music by themselves, but we hear them out of context. If we could listen to them all at once, fully orchestrated, in their immense ensemble, we might become aware of the counterpoint, the balance of tones and timbres and harmonics, the sonorities. The recorded songs of the humpback whale, filled with tensions and resolutions, ambiguities and allusions, incomplete, can be listened to as a part of music, like an isolated section of an orchestra. If we had better hearing, and could discern the descants of sea birds, the rhythmic tympani of schools of mollusks, or even the distant harmonics of midges hanging over meadows in the sun, the combined sound might lift us off our feet.
There are, of course, other ways to account for the songs of whales. They might be simple, down-to-earth statements about navigation, or sources of krill, or limits of territory. But the proof is not in, and until it is shown that these long, convoluted, insistent melodies, repeated by different singers with ornamentations of their own, are the means of sending through several hundred miles of undersea such ordinary information as “whale here,” I shall believe otherwise. Now and again, in the intervals between songs, the whales have been seen to breach, leaping clear out of the sea and landing on their backs, awash in the turbulence of their beating flippers. Perhaps they are pleased by the way the piece went, or perhaps it is celebration at hearing one’s own song returning after circumnavigation; whatever, it has the look of jubilation.
I suppose that my extraterrestrial Visitor night puzzle over my records in much the same way, on first listening. The 14th Quartet might, for him, be a communication announcing, “Beethoven here,” answered, after passage through an undersea of time and submerged currents of human thought, by another long signal a century later, “Bartok here.”
If, as I believe, the urge to make a kind of music is as much a characteristic of biology as our other fundamental functions, there ought to be an explanation for it. Having none at hand, I am free to make one up. The rhythmic sounds might be the recapitulation of something else—an earliest memory, a score for the transformation of inanimate, random matter in chaos into the improbable, ordered dance of living forms. Morowitz has presented the case, in thermodynamic terms, for the hypothesis that a steady flow of energy from the inexhaustible source of the sun to the unfillable sink of outer space, by way of the earth, is mathematically destined to cause the organization of matter into an increasingly ordered state. The resulting balancing act involves a ceaseless clustering of bonded atoms into molecules of higher and higher complexity, and the emergence of cycles for the storage and release of energy. In a nonequilibrium steady state, which is postulated, the solar energy would not just flow to the earth and radiate away; it is thermodynamically inevitable that it must rearrange matter into symmetry, away from probability, against entropy, lifting it, so to speak, into a constantly changing condition of rearrangement and molecular ornamentation. In such a system, the outcome is a chancy kind of order, always on the verge of descending into chaos, held taut against probability by the unremitting, constant surge of energy from the sun.
If there were to be sounds to represent this process, they would have the arrangement of the Brandenburg Concertos for my ear, but I am open to wonder whether the same events are recalled by the rhythms of insects, the long, pulsing runs of birdsong, the descants of whales, the modulated vibrations of a million locusts in migration, the tympani of gorilla breasts, termite heads, drumfish bladders. A “grand canonical ensemble” is, oddly enough, the proper term for a quantitative model system in thermodynamics, borrowed from music by way of mathematics. Borrowed back again, provided with notation, it would do for what I have in mind.
AN EARNEST PROPOSAL
There was a quarter-page advertisement in the London Observer for a computer service that will enmesh your name in an electronic network of fifty thousand other names, sort out your tastes, preferences, habits, and deepest desires and match them up with opposite numbers, and retrieve for you, within a matter of seconds, and for a very small fee, friends. “Already,” it says, “it [the computer] has given very real happiness and lasting relationships to thousands of people, and it can do the same for you!”
Without paying a fee, or filling out a questionnaire, all of us are being linked in similar circuits, for other reasons, by credit bureaus, the census, the tax people, the local police station, or the Army. Sooner or later, if it keeps on, the various networks will begin to touch, fuse, and then, in their coalescence, they will start sorting and retrieving each other, and we will all become bits of information on an enormous grid.
I do not worry much about the computers that are wired to help me find a friend among fifty thousand. If errors are made, I can always beg off with a headache. But what of the vaster machines that will be giving instructions to cities, to nations? If they are programmed to regulate human behavior according to today’s view of nature, we are surely in for apocalypse.
The men who run the affairs of nations today are, by and large, our practical men. They have been taught that the world is an arrangement of adversary systems, that force is what counts, aggression is what drives us at the core, only the fittest can survive, and only might can make more might. Thus, it is in observance of nature’s law that we have planted, like perennial tubers, the numberless nameless missiles in the soil of Russia and China and our Midwestern farmlands, with more to come, poised to fly out at a nanosecond’s notice, and meticulously engineered to ignite, in the centers of all our cities, artificial suns. If we let fly enough of them at once, we can even burn out the one-celled green creatures in the sea, and thus turn off the oxygen.
Before such things are done, one hopes that the computers will contain every least bit of relevant information about the way of the world. I should think we might assume this, in fairness to all. Even the nuclear realists, busy as their minds must be with calculations of acceptable levels of megadeath, would not want to overlook anything. They should be willing to wait, for a while anyway.
I have an earnest proposal to make. I suggest that we defer further action until we have acquired a really complete set of information concerning at least one living thing. Then, at least, we shall be able to claim that we know what we are doing. The delay might take a decade; let us say a decade. We and the other nations might set it as an objective of international, collaborative science to achieve a complete understanding of a single form of life. When this is done, and the information programmed into all our computers, I for one would be willing to take my chances.
As to the subject, I propose a simple one, easily solved within ten years. It is the protozoan Myxotricha paradoxa, which inhabits the inner reaches of the digestive tract of Australian termites.
It is not as though we would be starting from scratch. We have a fair amount of information about this creature already—not enough to understand him, of course, but enough to inform us that he means something, perhaps a great deal. At first glance, he appears to be an ordinary, motile protozoan, remarkable chiefly for the speed and directness with which he swims from place to place, engulfing fragments of wood finely chewed by his termite host. In the termite ecosystem, an arrangement of Byzantine complexity, he stands at the epicenter. Without him, the wood, however finely chewed, would never get digested; he supplies the enzymes that break down cellulose to edible carbohydrate, leaving only the nondegradable lignin, which the termite then excretes in geometrically tidy pellets and uses as building blocks for the erection of arches and vaults in the termite nest. Without him there would be no termites, no farms of the fungi that are cultivated by termites and will grow nowhere else, and no conversion of dead trees to loam.
The flagellae that beat in synchrony to propel myxotricha with such directness turn out, on closer scrutiny with the electron microscope, not to be flagellae at all. They are outsiders, in to help with the business: fully formed, perfect spirochetes that have attached themselves at regularly spaced intervals all over the surface of the protozoan.
Then, there are oval organelles, embedded in the surface close to the point of attachment of the spirochetes, and other similar bodies drifting through the cytoplasm with the particles of still undigested wood. These, under high magnification, turn out to be bacteria, living in symbiosis with the spirochetes and the protozoan, probably contributing enzymes that break down the cellulose.
The whole animal, or ecosystem, stuck for the time being halfway along in evolution, appears to be a model for the development of cells like our own. Margulis has summarized the now considerable body of data indicating that the modern nucleated cell was made up, part by part, by the coming together of just such prokaryotic animals. The blue-green algae, the original inventors of photosynthesis, entered partnership with primitive bacterial cells, and became the chloroplasts of plants; their descendants remain as discrete separate animals inside plant cells, with their own DNA and RNA, replicating on their own. Other bacteria with oxidative enzymes in their membranes, makers of ATP, joined up with fermenting bacteria and became the mitochondria of the future; they have since deleted some of their genes but retain personal genomes and can only be regarded as symbionts. Spirochetes, like the ones attached to M. paradoxa, joined up and became the cilia of eukaryotic cells. The centrioles, which hoist the microtubules on which chromosomes are strung for mitosis, are similar separate creatures; when not busy with mitosis, they become the basal bodies to which cilia are attached. And there are others, not yet clearly delineated, whose existence in the cell is indicated by the presence of cytoplasmic genes.
There is an underlying force that drives together the several creatures comprising myxotricha, and then drives the assemblage into union with the termite. If we could understand this tendency, we would catch a glimpse of the process that brought single separate cells together for the construction of metazoans, culminating in the invention of roses, dolphins, and, of course, ourselves. It might turn out that the same tendency underlies the joining of organisms into communities, communities into ecosystems, and ecosystems into the biosphere. If this is, in fact, the drift of things, the way of the world, we may come to view immune reactions, genes for the chemical marking of self, and perhaps all reflexive responses of aggression and defense as secondary developments in evolution, necessary for the regulation and modulation of symbiosis, not designed to break into the process, only to keep it from getting out of hand.
If it is in the nature of living things to pool resources, to fuse when possible, we would have a new way of accounting for the progressive enrichment and complexity of form in living things.
I take it on faith that computers, although lacking souls, are possessed of a kind of intelligence. At the end of the decade, therefore, I am willing to predict that the feeding in of all the information then available will result, after a few seconds of whirring, in something like the following message, neatly and speedily printed out: “Request more data. How are spirochetes attached? Do not fire.”
THE TECHNOLOGY OF MEDICINE
Technology assessment has become a routine exercise for the scientific enterprises on which the country is obliged to spend vast sums for its needs. Brainy committees are continually evaluating the effectiveness and cost of doing various things in space, defense, energy, transportation, and the like, to give advice about prudent investments for the future.
Somehow medicine, for all the $80-odd billion that it is said to cost the nation, has not yet come in for much of this analytical treatment. It seems taken for granted that the technology of medicine simply exists, take it or leave it, and the only major technologic problem which policy-makers are interested in is how to deliver today’s kind of health care, with equity, to all the people.
When, as is bound to happen sooner or later, the analysts get around to the technology of medicine itself, they will have to face the problem of measuring the relative cost and effectiveness of all the things that are done in the management of disease. They make their living at this kind of thing, and I wish them well, but I imagine they will have a bewildering time. For one thing, our methods of managing disease are constantly changing—partly under the influence of new bits of information brought in from all corners of biologic science. At the same time, a great many things are done that are not so closely related to science, some not related at all.
In fact, there are three quite different levels of technology in medicine, so unlike each other as to seem altogether different undertakings. Practitioners of medicine and the analysts will be in trouble if they are not kept separate.
1. First of all, there is a large body of what might be termed “nontechnology,” impossible to measure in terms of its capacity to alter either the natural course of disease or its eventual outcome. A great deal of money is spent on this. It is valued highly by the professionals as well as the patients. It consists of what is sometimes called “supportive therapy.” It tides patients over through diseases that are not, by and large, understood. It is what is meant by the phrases “caring for” and “standing by.” It is indispensable. It is not, however, a technology in any real sense, since it does not involve measures directed at the underlying mechanism of disease.
It includes the large part of any good doctor’s time that is taken up with simply providing reassurance, explaining to patients who fear that they have contracted one or another lethal disease that they are, in fact, quite healthy.
It is what physicians used to be engaged in at the bedside of patients with diphtheria, meningitis, poliomyelitis, lobar pneumonia, and all the rest of the infectious diseases that have since come under control.
It is
what physicians must now do for patients with intractable cancer, severe rheumatoid arthritis, multiple sclerosis, stroke, and advanced cirrhosis. One can think of at least twenty major diseases that require this kind of supportive medical care because of the absence of an effective technology. I would include a large amount of what is called mental disease, and most varieties of cancer, in this category.
The cost of this nontechnology is very high, and getting higher all the time. It requires not only a great deal of time but also very hard effort and skill on the part of physicians; only the very best of doctors are good at coping with this kind of defeat. It also involves long periods of hospitalization, lots of nursing, lots of involvement of nonmedical professionals in and out of the hospital. It represents, in short, a substantial segment of today’s expenditures for health.
2. At the next level up is a kind of technology best termed “halfway technology.” This represents the kinds of things that must be done after the fact, in efforts to compensate for the incapacitating effects of certain diseases whose course one is unable to do very much about. It is a technology designed to make up for disease, or to postpone death.
The outstanding examples in recent years are the transplantations of hearts, kidneys, livers, and other organs, and the equally spectacular inventions of artificial organs. In the public mind, this kind of technology has come to seem like the equivalent of the high technologies of the physical sciences. The media tend to present each new procedure as though it represented a breakthrough and therapeutic triumph, instead of the makeshift that it really is.