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Silent Spring. SUENT. SPRING. FORTIETH ANNIVERSARY EDITION. RACHEL. CARSON. Introduction by Linda Lear. Afterword by. Edward 0. Wilson. A MARINER BOOK.
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BY RACHEL CARSON
The Sea Around Us
Silent Spring
FORTIETH ANNIVERSARY EDITION
CARSON
A MARINER BOOK HOUGHTON M1FFLIN COMPANY Boston New York
Introduction
by Linda Lear
Headlines in the New York Times in July 1962 captured the national sentiment: "Silent Spring is now noisy summer." In the few months between the New Yorker's serialization of Silent Spring in June and its publication in book form that September, Rachel Carson's alarm touched off a national debate on the use of chemical pesticides, the responsibility of science, and the lim its of technological progress. When Carson died barely eighteen months later in the spring of 1964, at the age of fifty-six, she had set in motion a course of events that would result in a ban on the domestic production of DDT and the creation of a grass-roots movement demanding protection of the environment through state and federal regulation. Carson's writing initiated a trans formation in the relationship between humans and the natural world and stirred an awakening of public environmental con sciousness. It is hard to remember the cultural climate that greeted Silent Spring and to understand the fury that was launched against its quietly determined author. Carson's thesis that we were sub jecting ourselves to slow poisoning by the misuse of chemical pesticides that polluted the environment may seem like common currency now, but in 1962 Silent Spring contained the kernel of social revolution. Carson wrote at a time of new affluence and intense social conformity. The cold war, with its climate of suspi cion and intolerance, was at its zenith. The chemical industry, one of the chief beneficiaries of postwar technology, was also one of the chief authors of the nation's prosperity. DDT enabled the conquest of insect pests in agriculture and of ancient insect- borne disease just as surely as the atomic bomb destroyed Amer-
INTRODUCTION XI ica's military enemies and dramatically altered the balance of power between humans and nature. The public endowed chemists, at work in their starched white coats in remote labora tories, with almost divine wisdom. The results of their labors
tific establishment, first because she was a woman but also be cause her chosen field, biology, was held in low esteem in the
mous detriment. But by the time Silent Spring was published,
the science establishment would discover, it was impossible to dismiss her.
Rachel Carson first discovered nature in the company of her mother, a devotee of the nature study movement. She wandered the banks of the Allegheny River in the pristine village of Springdale, Pennsylvania, just north of Pittsburgh, observing the wildlife and plants around her and particularly curious about the habits of birds. Her childhood, though isolated by poverty and family tur moil, was not lonely. She loved to read and displayed an obvious talent for writing, publishing her first story in a children's liter ary magazine at the age of ten. By the time she entered Pennsyl vania College for Women (now Chatham College), she had read widely in the English Romantic tradition and had articulated a personal sense of mission, her "vision splendid." A dynamic fe male zoology professor expanded her intellectual horizons by urging her to take the daring step of majoring in biology rather
only engaged her mind but gave her "something to write about."
XIV INTRODUCTION writing. It took her ten years to synthesize the latest research on oceanography, but her perseverance paid off. She became an overnight literary celebrity when The Sea Around Us was first se rialized in The New Yorker in 1951. The book won many awards, including the National Book Award for nonnction, and Carson was elected to the American Academy of Arts and Letters. She was lauded not only for her scientific expertise and synthesis of wide-ranging material but also for her lyrical, poetic voice. The Sea Around Us and its best-selling successor, The Edge of the Sea, made Rachel Carson the foremost science writer in America. She understood that there was a deep need for writers who could re port on and interpret the natural world. Readers around the world found comfort in her clear explanations of complex sci ence, her description of the creation of the seas, and her obvious love of the wonders of nature. Hers was a trusted voice in a world riddled by uncertainty. Whenever she spoke in public, however, she took notice of ominous new trends. "Intoxicated with a sense of his own power," she wrote, "[mankind] seems to be going farther and farther into more experiments for the destruction of himself and his world." Technology, she feared, was moving on a faster trajectory than mankind's sense of moral responsibility. In 1945 she tried to in terest Readers Digest in the alarming evidence of environmental damage from the widespread use of the new synthetic chemical DDT and other long-lasting agricultural pesticides. By 1957 Carson believed that these chemicals were potentially harmful to the long-term health of the whole biota. The pollution of the environment by the profligate use of toxic chemicals was the ultimate act of human hubris, a product of ignorance and greed that she felt compelled to bear witness against. She insisted that what science conceived and technology made possible must first be judged for its safety and benefit to the "whole stream of life." "There would be no peace for me, she wrote to a friend, "if I kept silent."
INTRODUCTION XV
put into the environment before knowing the long-term conse quences of their use. Writing in language that everyone could
'biocides.'"
sons." Through ignorance, greed, and negligence, government
know." In Carson's view, the postwar culture of science that arro-
XVI (^) INTRODUCTION
gantly claimed dominion over nature was the philosophic root of the problem. Human beings, she insisted, were not in control of nature but simply one of its parts: the survival of one part de pended upon the health of all. She protested the "contamination of man's total environment" with substances that accumulate in the tissues of plants, animals, and humans and have the potential to alter the genetic structure of organisms. Carson argued that the human body was permeable and, as such, vulnerable to toxic substances in the environment. Levels of exposure could not be controlled, and scientists could not ac curately predict the long-term effects of bioaccumulation in the cells or the impact of such a mixture of chemicals on human health. She categorically rejected the notion proposed by indus try that there were human "thresholds" for such poisons, as well as its corollary, that the human body had "assimilative capacities" that rendered the poisons harmless. In one of the most contro versial parts of her book, Carson presented evidence that some human cancers were linked to pesticide exposure. That evidence and its subsequent elaboration by many other researchers con tinue to fuel one of the most challenging and acrimonious de bates within the scientific and environmental communities. Carson's concept of the ecology of the human body was a major departure in our thinking about the relationship between humans and the natural environment. It had enormous conse quences for our understanding of human health as well as our at titudes toward environmental risk. Silent Spring proved that our bodies are not boundaries. Chemical corruption of the globe af fects us from conception to death. Like the rest of nature, we are vulnerable to pesticides; we too are permeable. All forms of life are more alike than different. Carson believed that human health would ultimately reflect the environment's ills. Inevitably this idea has changed our re sponse to nature, to science, and to the technologies that devise and deliver contamination. Although the scientific community
INTRODUCTION XV has been slow to acknowledge this aspect of Carson's work, her concept of the ecology of the human body may well prove to be one of her most lasting contributions. In 1962, however, the multimillion-dollar industrial chemical industry was not about to allow a former government editor, a female scientist without a Ph.D. or an institutional affiliation, known only for her lyrical books on the sea, to undermine public confidence in its products or to question its integrity. It was clear to the industry that Rachel Carson was a hysterical woman whose alarming view of the future could be ignored or, if neces sary, suppressed. She was a "bird and bunny lover," a woman
mantic "spinster" who was simply overwrought about genetics. In short, Carson was a woman out of control. She had over stepped the bounds of her gender and her science. But just in case her claims did gain an audience, the industry spent a quarter of a million dollars to discredit her research and malign her char acter. In the end, the worst they could say was that she had told only one side of the story and had based her argument on unver- ifiable case studies. There is another, private side to the controversy over Silent Spring, Unbeknown to her detractors in government and indus try, Carson was fighting a far more powerful enemy than corpo rate outrage: a rapidly metastasizing breast cancer. The miracle is that she lived to complete the book at all, enduring a "cata logue of illnesses," as she called it. She was immune to the chem ical industry's efforts to malign her; rather, her energies were fo cused on the challenge of survival in order to bear witness to the truth as she saw it. She intended to disturb and disrupt, and she did so with dignity and deliberation. After Silent Spring caught the attention of President John F. Kennedy, federal and state investigations were launched into the validity of Carson's claims. Communities that had been sub jected to aerial spraying of pesticides against their wishes began
i. A Fable for Tomorrow
There was once a town in the heart of America where all life seemed to live in harmony with its surroundings. The town lay in the midst of a checkerboard of prosperous farms, with fields of grain and hillsides of orchards where, in spring, white clouds of bloom drifted above the green fields. In autumn, oak
flickered across a backdrop of pines. Then foxes barked in the hills and deer silently crossed the fields, half hidden in the mists of the fall mornings. Along the roads, laurel, viburnum and alder, great ferns and wildflpwers delighted the traveler's eye through much of the
2 SILENT SPRING year. Even in winter the roadsides were places of beauty, where countless birds came to feed on the berries and on the seed heads of the dried weeds rising above the snow. The countryside was, in fact, famous for the abundance and variety of its bird life, and when the flood of migrants was pouring
to observe them. Others came to fish the streams, which flowed
trout lay. So it had been from the days many years ago when
their barns.
mysterious maladies swept the flocks of chickens; the cattle and
over the fields and woods and marsh.
A FABLE FOR TOMORROW 3 among the blossoms, so there was no pollination and there would be no fruit. The roadsides, once so attractive, were now lined with browned and withered vegetation as though swept by fire. These, too, were silent, deserted by all living things. Even the streams were now lifeless. Anglers no longer visited them, for all the fish had died. In the gutters under the eaves and between the shingles of the roofs, a white granular powder still showed a few patches; some weeks before it had fallen like snow upon the roofs and the lawns, the fields and streams. No witchcraft, no enemy action had silenced the rebirth of new life in this stricken world. The people had done it them selves.
This town does not actually exist, but it might easily have a thousand counterparts in America or elsewhere in the world. I know of no community that has experienced all the misfor tunes I describe. Yet every one of these disasters has actually happened somewhere, and many real communities have already suffered a substantial number of them. A grim specter has crept upon us almost unnoticed, and this imagined tragedy may easily become a stark reality we all shall know. What has already silenced the voices of spring in countless towns in America? This book is an attempt to explain.
SILENT SPRING in character. The most alarming of all man's assaults upon the environment is the contamination of air, earth, rivers, and sea
ination of the environment, chemicals are the sinister and little- recognized partners of radiation in changing the very nature
leased through nuclear explosions into the air, comes to earth in
or corn or wheat grown there, and in time takes up its abode in
one to another in a chain of poisoning and death. Or they pass
harm on those who drink from once pure wells. As Albert
of his own creation."
veloping and evolving and diversifying life reached a state of
ment, rigorously shaping and directing the life it supported, contained elements that were hostile as well as supporting. Cer tain rocks gave out dangerous radiation; even within the light
short-wave radiations with power to injure. Given time —
the modern world there is no time.
THE OBLIGATION TO ENDURE 7
of cosmic raysrthe ultraviolet of the sun that have existed before
life is asked to make its adjustment are no longer merely the
come from our laboratories in an endless stream; almost five
States alone. The figure is staggering and its implications are
chemicals totally outside the limits of biologic experience. Among them are many that are used in man's war against
been created for use in killing insects, weeds, rodents, and other
they are sold under several thousand different brand names. These sprays, dusts, and aerosols are now applied almost uni
chemicals that have the power to kill every insect, the "good"
in the streams, to coat the leaves with a deadly film, and to linger on in soil — all this though the intended target may be
8 SILENT SPRING
to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life? They should not be called "insecticides," but "biocides." The whole process of spraying seems caught up in an endless spiral. Since DDT was released for civilian use, a process of escalation has been going on in which ever more toxic materials must be found. This has happened because insects, in a trium phant vindication of Darwin's principle of the survival of the fittest, have evolved super races immune to the particular in secticide used, hence a deadlier one has always to be developed — and then a deadlier one than that. It has happened also be cause, for reasons to be described later, destructive insects often undergo a "flareback," or resurgence, after spraying, in numbers greater than before. Thus the chemical war is never won, and all life is caught in its violent crossfire. Along with the possibility of the extinction of mankind by nuclear war, the central problem of our age has therefore be come the contamination of man's total environment with such substances of incredible potential for harm — substances that accumulate in the tissues of plants and animals and even pene trate the germ cells to shatter or alter the very material of heredity upon which the shape of the future depends. Some would-be architects of our future look toward a time when it will be possible to alter the human germ plasm by design. But we may easily be doing so now by inadvertence, for many chemicals, like radiation, bring about gene mutations. It is ironic to think that man might determine his own future by something so seemingly trivial as the choice of an insect spray. All this has been risked — for what? Future historians may well be amazed by our distorted sense of proportion. How could intelligent beings seek to control a few unwanted species by a method that contaminated the entire environment and brought the threat of disease and death even to their own kind?
THE OBLIGATION TO ENDURE 9 Yet this is precisely what we have done. We have done it, moreover, for reasons that collapse the moment we examine them. We are told that the enormous and expanding use of pesticides is necessary to maintain farm production. Yet is our real problem not one of overproduction? Our farms, despite measures to remove acreages from production and to pay farmers not to produce, have yielded such a staggering excess of crops that the American taxpayer in 1962 is paying out more than one billion dollars a year as the total carrying cost of the surplus-food storage program. And is the situation helped when one branch of the Agriculture Department tries to reduce production while another states, as it did in 1958, "It is believed generally that reduction of crop acreages under provisions of the Soil Bank will stimulate interest in use of chemicals to obtain maximum production on the land retained in crops." All this is not to say there is no insect problem and no need of control. I am saying, rather, that control must be geared to realities, not to mythical situations, and that the methods em ployed must be such that they do not destroy us along with the insects.
The problem whose attempted solution has brought such a train of disaster in its wake is an accompaniment of our modern way of life. Long before the age of man, insects inhabited the earth — a group of extraordinarily varied and adaptable beings. Over the course of time since man's advent, a small percentage of the more than half a million species of insects have come into conflict with human welfare in two principal ways: as competitors for the food supply and as carriers of human disease. Disease-carrying insects become important where human be ings are crowded together, especially under conditions where sanitation is poor, as in time of natural disaster or war or in situations of extreme poverty and deprivation. Then control of some sort becomes necessary. It is a sobering fact, however,
SILENT SPRING
he lives in the most isolated situation imaginable. Lulled by the soft sell and the hidden persuader, the average citizen is seldom aware of the deadly materials with which he is surrounding him self; indeed, he may not realize he is using them at all. So thoroughly has the age of poisons become established that anyone may walk into a store and, without questions being asked, buy substances of far greater death-dealing power than the medicinal drug for which he may be required to sign a "poi son book" in the pharmacy next door. A few minutes' research in any supermarket is enough to alarm the most stouthearted customer — provided, that is, he has even a rudimentary knowl edge of the chemicals presented for his choice. If a huge skull and crossbones were suspended above the in secticide department the customer might at least enter it with the respect normally accorded death-dealing materials. But in stead the display is homey and cheerful, and, with the pickles
joining, the rows upon rows of insecticides are displayed. Within easy reach of a child's exploring hand are chemicals in glass containers. If dropped to the floor by a child or careless adult everyone nearby could be splashed with the same chem ical that has sent spraymen using it into convulsions. These hazards of course follow the purchaser right into his home. A can of a mothproofing material containing DDD, for example, carries in very fine print the warning that its contents are under
A common insecticide for household use, including assorted uses in the kitchen, is chlordane. Yet the Food and Drug Ad ministration's chief pharmacologist has declared the hazard of living in a house sprayed with chlordane to be "very great."
dieldrin. Use of poisons in the kitchen is made both attractive and easy. Kitchen shelf paper, white or tinted to match one's color scheme,
BEYOND THE DREAMS OF THE BORGIAS 175
how to kill bugs. With push-button ease, one may send a fog of dieldrin into the most inaccessible nooks and crannies of cabinets, corners, and baseboards.
creams, and sprays for application to clothing or skin. Although
skin is impervious to chemicals. To make certain that we shall at all times be prepared to repel insects, an exclusive New York
the purse or for beach, golf, or fishing gear.
insect that walks over it. We can hang strips impregnated with the chemical lindane in our closets and garment bags or place them in our bureau drawers for a half year's freedom from
gestion that lindane is dangerous. Neither do the ads for an electronic device that dispenses lindane fumes —we are told that it is safe and odorless. Yet the truth of the matter is that
so dangerous that it conducted an extended campaign against them in its Journal The Department of Agriculture, in a Home and Garden Bul letin, advises us to spray our clothing with oil solutions of DDT, dieldrin, chlordane, or any of several other moth killers. If ex cessive spraying results in a white deposit of insecticide on the fabric, this may be removed by brushing, the Department says, omitting to caution us to be careful where and how the brush
our day with insecticides by going to sleep under a mothproof blanket impregnated with dieldrin.
176 SILENT SPRING
Gardening is now firmly linked with the super poisons. Every
of insecticides for every conceivable horticultural situation. Those who fail to make wide use of this array of lethal sprays and dusts are by implication remiss, for almost every news paper's garden page and the majority of the gardening maga zines take their use for granted. So extensively are even the rapidly lethal organic phosphorus insecticides applied to lawns and ornamental plants that in i
the commercial use of pesticides in residential areas by anyone who had not first obtained a permit and met certain require ments. A number of deaths from parathion had occurred in Florida before this regulation was adopted. Little is done, however, to warn the gardener or homeowner that he is handling extremely dangerous materials. On the con trary, a constant stream of new gadgets make it easier to use poisons on lawn and garden — and increase the gardener's con tact with them. One may get a jar-type attachment for the garden hose, for example, by which such extremely dangerous chemicals as chlordane or dieldrin are applied as one waters the lawn. Such a device is not only a hazard to the person using the hose; it is also a public menace. The New York Times found it necessary to issue a warning on its garden page to the effect that unless special protective devices were installed poisons might get into the water supply by back siphonage. Considering the num ber of such devices that are in use, and the scarcity of warnings such as this, do we need to wonder why our public waters are contaminated?
we might look at the case of a physician — an enthusiastic spare- time gardener — who began using DDT and then malathion on his shrubs and lawn, making regular weekly applications. Some times he applied the chemicals with a hand spray, sometimes
BEYOND THE DREAMS OF THE BORGIAS IJJ with an attachment to his hose. In doing so, his skin and cloth ing were often soaked with spray. After about a year of this sort of thing, he suddenly collapsed and was hospitalized. Ex amination of a biopsy specimen of fat showed an accumulation of 23 parts per million of DDT. There was extensive nerve damage, which his physicians regarded as permanent. As time went on he lost weight, suffered extreme fatigue, and experi enced a peculiar muscular weakness, a characteristic effect of malathion. All of these persisting effects were severe enough to make it difficult for the physician to carry on his practice. Besides the once innocuous garden hose, power mowers also have been fitted with devices for the dissemination of pesticides, attachments that will dispense a cloud of vapor as the homeowner goes about the task of mowing his lawn. So to the potentially dangerous fumes from gasoline are added the finely divided particles of whatever insecticide the probably unsuspecting suburbanite has chosen to distribute, raising the level of air pollution above his own grounds to something few cities could equal. Yet little is said about the hazards of the fad of gardening by poisons, or of insecticides used in the home; warnings on labels are printed so inconspicuously in small type that few take the trouble to read or follow them. An industrial firm recently undertook to find out just bow few. Its survey indicated that fewer than fifteen people out of a hundred of those using in secticide aerosols and sprays are even aware of the warnings on the containers. The mores of suburbia now dictate that crabgrass must go at whatever cost. Sacks containing chemicals designed to rid the lawn of such despised vegetation have become almost a status symbol. These weed-killing chemicals are sold under brand names that never suggest their identity or nature. To learn that they contain chlordane or dieldrin one must read exceedingly fine print placed on the least conspicuous part of the sack. The
i8o SILENT SPRING samples were taken from people who had left their native vil lages to enter the United States Public Health Service Hospital in Anchorage for surgery. There the ways of civilization pre vailed, and the meals in this hospital were found to contain as much DDT as those in the most populous city. For their brief stay in civilization the Eskimos were rewarded with a taint of poison. The fact that every meal we eat carries its load of chlorinated hydrocarbons is the inevitable consequence of the almost uni versal spraying or dusting of agricultural crops with these poi sons. If the farmer scrupulously follows the instructions on the labels, his use of agricultural chemicals will produce no residues larger than are permitted by the Food and Drug Administration. Leaving aside for the moment the question whether these legal residues are as "safe" as they are represented to be, there remains the well-known fact that farmers very frequently exceed the prescribed dosages, use the chemical too close to the time of har vest, use several insecticides where one would do, and in other ways display the common human failure to read the fine print. Even the chemical industry recognizes the frequent misuse of insecticides and the need for education of farmers. One of its leading trade journals recently declared that "many users do not seem to understand that they may exceed insecticide toler ances if they use higher dosages than recommended. And hap hazard use of insecticides on many crops may be based on farmers' whims." The files of the Food and Drug Administration contain records of a disturbing number of such violations. A few ex amples will serve to illustrate the disregard of directions: a let tuce farmer who applied not one but eight different insecticides to his crop within a short time of harvest, a shipper who had used the deadly parathion on celery in an amount five times the recommended maximum, growers using endrin — most toxic of all the chlorinated hydrocarbons — on lettuce although no resi-
BEYOND THE DREAMS OF THE BORGIAS l8l
harvest.
Large lots of green coffee in burlap bags have become con
and occur in measurable quantities on the contained foods. The
contamination.
600 men for all its varied work. According to a Food and Drug
inadequate laws in this field. The system by which the Food and Drug Administration establishes maximum permissible limits of contamination, called "tolerances," has obvious defects. Under the conditions pre vailing it provides mere paper security and promotes a com
(^182) SILENT SPRING
different from a human being whose exposures to pesticides are
later reduction or withdrawal of the tolerance, but only after the public has been exposed to admittedly dangerous levels of the chemical for months or years. This happened when hepta- chlor was given a tolerance that later had to be revoked. For
fore a chemical is registered for use* Inspectors are therefore frustrated in their search for residues. This difficulty greatly hampered the work on the "cranberry chemical," aminotriazole.
BEYOND THE DREAMS OF THE BORGIAS 183 at the end of the planting season, may very well find their way into human food. In effect, then, to establish tolerances is to authorize con tamination of public food supplies with poisonous chemicals in order that the farmer and the processor may enjoy the benefit
ing him to maintain a policing agency to make certain that he shall not get a lethal dose. But to do the policing job properly would cost money beyond any legislator's courage to appro priate, given the present volume and toxicity of agricultural chemicals. So in the end the luckless consumer pays his taxes but gets his poisons regardless. What is the solution? The first necessity is the elimination of tolerances on the chlorinated hydrocarbons, the organic phos phorus group, and other highly toxic chemicals. It will im mediately be objected that this will place an intolerable burden on the farmer. But if, as is now the presumable goal, it is pos sible to use chemicals in such a way that they leave a residue of only 7 parts per million (the tolerance for DDT), or of i part per million (the tolerance for parathion), or even of only o.i part per million as is required for dieldrin on a great variety of fruits and vegetables, then why is it not possible, with only a little more care, to prevent the occurrence of any residues at all? This, in fact, is what is required for some chemicals such as heptachlor, endrin, and dieldrin on certain crops. If it is con sidered practical in these instances, why not for all? But this is not a complete or final solution, for a zero tolerance on paper is of little value. At present, as we have seen, more than 99 per cent of the interstate food shipments slip by without inspection. A vigilant and aggressive Food and Drug Admin istration, with a greatly increased force of inspectors, is another urgent need. This system, however — deliberately poisoning our food, then policing the result — is too reminiscent of Lewis Carroll's White
. The Human Price
As the tide of chemicals born of the Industrial Age has arisen to engulf our environment, a drastic change has come about in the nature of the most serious public health problems. Only yesterday mankind lived in fear of the scourges of smallpox, cholera, and plague that once swept nations before them. Now our major concern is no longer with the disease organisms that once were omnipresent; sanitation, better living conditions, and new drugs have given us a high degree of control over infectious disease. Today we are concerned with a different kind of haz ard that lurks in our environment — a hazard we ourselves have introduced into our world as our modern way of life has evolved.
l88 SILENT SPRING The new environmental health problems are multiple — created by radiation in all its forms, born of the never-ending stream of chemicals of which pesticides are a part, chemicals now pervading the world in which we live, acting upon us directly and indirectly, separately and collectively. Their pres ence casts a shadow that is no less ominous because it is formless and obscure, no less frightening because it is simply impossible to predict the effects of lifetime exposure to chemical and phys ical agents that are not part of the biological experience of man. "We all live under the haunting fear that something may cor rupt the environment to the point where man joins the dinosaurs as an obsolete form of life," says Dr. David Price of the United States Public Health Service. "And what makes these thoughts all the more disturbing is the knowledge that our fate could perhaps be sealed twenty or more years before the development of symptoms." Where do pesticides fit into the picture of environmental dis
food, that they have the power to make our streams fishless and our gardens and woodlands silent and birdless. Man, however much he may like to pretend the contrary, is part of nature. Can he escape a pollution that is now so thoroughly distributed throughout our world?
amount is large enough, can precipitate acute poisoning. But
farmers, spraymen, pilots, and others exposed to appreciable quantities of pesticides are tragic and should not occur. For the population as a whole, we must be more concerned with the delayed effects of absorbing small amounts of the pesticides that invisibly contaminate our world. Responsible public health officials have pointed out that the biological effects of chemicals are cumulative over long periods
THE HUMAN PRICE 189 sum of the exposures received throughout his lifetime. For these very reasons the danger is easily ignored. It is human nature to shrug off what may seem to us a vague threat of future disaster. "Men are naturally most impressed by diseases which have obvious manifestations," says a wise physician, Dr. Rene Dubos, "yet some of their worst enemies creep on them unob trusively." For each of us, as for the robin in Michigan or the salmon in the Miramichi, this is a problem of ecology, of interrelation ships, of interdependence. We poison the caddis flies in a stream and the salmon runs dwindle and die. We poison the gnats in a lake and the poison travels from link to link of the food chain and soon the birds of the lake margins become its victims. We spray our elms and the following springs are silent of robin song, not because we sprayed the robins directly but because the poi son traveled, step by step, through the now familiar elm leaf- earthworm-robin cycle. These are matters of record, observ able, part of the visible world around us. They reflect the web of life — or death — that scientists know as ecology. But there is also an ecology of the world within our bodies. In this unseen world minute causes produce mighty effects; the effect, moreover, is often seemingly unrelated to the cause, ap pearing in a part of the body remote from the area where the original injury was sustained. "A change at one point, in one molecule even, may reverberate throughout the entire system to initiate changes in seemingly unrelated organs and tissues," says a recent summary of the present status of medical research. When one is concerned with the mysterious and wonderful functioning of the human body, cause and effect are seldom simple and easily demonstrated relationships. They may be widely separated both in space and time. To discover the agent of disease and death depends on a patient piecing together of many seemingly distinct and unrelated facts developed through a vast amount of research in widely separated fields.
