现代大学英语精读第三册 11b

　　Lesson eleven

Silent spring

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 prosperous farms, where, in spring, white clouds of bloom drifted above the green fields. In autumn, oak and maple 1 and birch set up a blaze of color that flamed and flickered 2 across a background of pines. Then foxes barked in the hills and deer silently crossed the fields.

Along the roads, laurel, great ferns and wildflowers delighted the traveler’s eye through much of the year. Even in winter the roadsides were places of beauty, where countless 3 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 through in spring and fall people traveled from great distances to observe them. Others came to fish the streams, which flowed clear and cold out of the hills and contained shady pools where trout 4 lay. So it had been from the days many years ago when the first settlers raised their houses, sank their wells, and built their barns.

Then some evil spell settled on the community: mysterious diseases swept the flocks of chickens; the cattle and sheep sickened and died. In the town the doctors became more and more puzzled by new kinds of sickness appearing among their patients. There had been several sudden and unexplained deaths, not only among adults but even among children.

There was a strange stillness. The birds, for example---where had they gone? The feeding stations in the backyards were deserted 5. The few birds seen anywhere trembled violently and could not fly. It was a spring without voices there was now no sound; only silence lay over the fields and woods and marsh 6.

The roadsides, once so attractive, were now lined with browned and withered 7 vegetation as though swept by fire. There, 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.

Some weeks before a white powder had fallen like snow upon the roofs and the lawns, the fields and streams.

No witchcraft 8, no enemy action had silenced the rebirth of new life in this in this stricken world. The people had done it themselves.

This town does not actually exist. I know of no community that has experienced all the misfortunes I describe. Yet every one of these disasters has actually happened somewhere, and many real communities have already suffered a substantial number of them, and this imagined tragedy may easily become a harsh 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.

The history of life on earth has been a history of interaction between living things and their surroundings. To a large extent, the physical form and the habits of the earth’s vegetation and its animal life have been molded by the environment. Considering the whole span of earthly time, the opposite effect, in which life actually modifies its surroundings, has been relatively 9 slight. Only in the present century has one species----man---acquired significant power to alter the nature of his world.

During the past quarter century this power has not only become increasingly great but it has changed in character. The most alarming of all man’s assaults upon the environment is the contamination of air, earth, rivers, and sea with dangerous and even lethal 10 materials. This pollution is for the most part irrecoverable. In this now universal contamination of the environment, chemicals are the sinister 11 partners of radiation in changing the very nature of the world ---the very nature of its life. Chemicals sprayed on croplands or forests or gardens lie long in soil, entering into living organisms, passing from one to another in a chain of poisoning and death. Or they pass mysteriously by underground streams until they emerge and work unknown harm on those who drink from once pure wells. “Man can hardly even recognize the devils of his own creation.” as a scientist has said.

It took hundreds of millions of years to produce the life that now inhabits the earth. Given time---time not in years but in millennia---life adjusts, and a balance has been reached. But in the modern world there is no time.

The rapidity of change follows the impetuous pace of man rather than the deliberate pace of nature. Radiation is now the unnatural 12 creation of man’s tampering 13 with the atom. The chemicals are the synthetic 14 creations of man’s inventive mind, having no counterparts in nature.

To adjust to these chemicals would require not merely the years a man’s life but the life of generations. And even this, were it by some miracle possible, would be futile 15, for the new chemicals come from our laboratories in an endless stream; almost five hundred annually 16 find their way into actual use in the United States alone.

Among them are many that are used in man’s war against nature. Since the mid-1904’s over 200 basic chemicals have been created for use in killing 17 insects, weeds, and other organisms described as “pests”; and they are sold under several thousand different brand names.

There chemicals are now applied 18 almost universally to farms, gardens, forests, and homes, killing every insect, the “good” and the “bad”, to still the song of birds and the leaping of fish, to coat the leaves with a deadly film, and to linger on in soil---all this though the intended target may be only a few weeds or insects. Can anyone believe it is possible to lay down such a large number 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. This has happened because insects, in Darwin’s principle of the survival of the fittest, have evolved super races immune to the particular insecticide used, hence a deadlier one has always to be developed and then a deadlier one than that. It has happened also because destructive insects often undergo a “flare-back”, or resurgence 19, after spraying, in numbers greater than before. Thus the chemicals war is never won, and all life is caught in its violent crossfire 20.

How could intelligent begins 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? Yet this is precisely 21 what we have done.

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, and that the methods employs employed must be such that they do not destroy us along with the insects.

Under primitive 22 agricultural conditions the farmer had few insect problems. Name has introduced great variety into the landscape and holds the species within bounds by the built-in checks and balances. One important natural check is a limit on the amount of suitable habitat for each species. Insect problems arose with the intensification 23 of agriculture---the devotion of immense acreage to a single crop. Such a system set the stage for explosive increases in specific insect population. Obviously then, an insect that lives on wheat can build up its population to much higher levels on a farm devoted 24 to wheat than on one in which wheat is intermingled with other crops to which the insect is not adapted.

Another factor in the modern insect problem is the spreading of thousands of different kinds of organisms from their native homes. Some hundred million years ago, flooding seas cut many land bridges between continents and living things found themselves confined in what an ecologist calls “colossal separate nature reserves”. There, isolated 25 from others of their kind, they developed many new species. When some of the land masses were joined again, about 15 million years ago, these species began to move out into new territories---a movement that is not only still in progress but is now receiving considerable assistance from man.

The important of plants is the primary agent in the modern spread of species, for animals have almost invariably gone along with the plants. Nearly half of the 180 or so major insect enemies of plants in the United States are accidental imports from abroad, and most of them have come as hitchhikers on plants.

In new territory, out of reach of the restraining hand of the natural enemies that kept down its numbers in its native land, an invading plant or animal is able to become enormously abundant. Thus it is no accident that our most troublesome insects are introduced species.

We are faced, according to Dr. Elton, “with a life-and –death need not just to find new technological 26 means of suppressing this plant or that animal”; instead we need the basic knowledge of animal populations and their relations to their surroundings that will “promote an even balance and damp down the explosive power of outbreaks and new invasions”.

It is not my contention 27 that chemical insecticides must never be used. I do contend that we have put poisonous and biologically potent 28 chemicals indiscriminately into the hands of persons largely or wholly ignorant of their potentials for harm. We have subjected enormous numbers of people to contact with these poisons, without their consent and often without their knowledge. I contend, furthermore, that we have allowed these chemicals to be used with little or no advance investigation 29 of their effect on soil, water, wildlife, and man himself. Future generations are unlikely to forgive our lack of concern for the integrity of the natural world that supports all life.