Do we still live amid “a forest of symbols,” as Baudelaire put it in a famous sonnet from “Flowers of Evil”? Is everything in the world – dumb objects, other creatures, we ourselves – merely a shadow of something else? This ultimately Platonic view, as mediated to the French Symbolists via the visionary philosopher Emanuel Swedenborg, holds that interpreting the world involves a kind of deciphering, as though everything we encountered in life were, in Emerson’s words, some “ambassador of the infinite.” From this perspective, the poet, the philosopher, and the theosophist play the part of metaphysical dragomans, interpreting phenomena in their suprasensual, and true, reality for the rest of us. I used to be drawn to this persuasion; it seemed to recognize the hidden depth of the world. Now, though, I’m no longer so sure.

Doesn’t such a view vitiate the richness of the world? When Hopkins wrote, “There lives the dearest freshness deep down things,” we know at once what he meant: The inexhaustible particularity of each thing enchants; what it is in itself, as an individual instance of nothing beyond itself, captures our imaginations, even if we know all too well that what it is “in itself” escapes us forever. Against the Symbolists I would cite Whitman, who witnessed prodigies in a blade of grass and wrote, “A mouse is miracle enough to stagger sextillions of infidels” and again, tipping toward that near absurdity that so endears him to us, “Do not call the tortoise unworthy because she is not something else.” Yet, if things are nothing other than what they are in themselves, how can we speak of them in any meaningful general way?

For this we must turn to the scientists, not the poets. But scientists by and large have scant regard for language, too often resorting to awful technical jargon. Sometimes scientists write very well: Darwin, Haldane, and Loren Eiseley come immediately to mind as often superb writers in their own right. When minute powers of observation are combined with a feeling for language, the results can be spectacular. The American biologist David G. Campbell proves my case.

His latest book, “A Land of Ghosts: The Braided Lives of People and the Forest in Far Western Amazonia” (Houghton Mifflin, 260 pages, $25), seamlessly joins meticulous scrutiny of plants, animals, and people with a prose of exquisite precision. It wouldn’t be much of a compliment to Mr. Campbell to say that he writes like a poet. Would that our poets could write as well as he does! But maybe we could say he writes as a real poet should, with rigor and an almost unerring sense of the apposite: His language is so perfectly attuned to his subject that we start with recognition when we read him.

Mr. Campbell’s specialty is mapping growth and change in selected tracts of the Brazilian rainforest, particularly in the remote western regions. But he is equally sensitive to the human inhabitants of this wilderness and has a special feeling for the caboclos – subsistence farmers of mixed lineage, Native American with European, African, and Middle Eastern strains – who have often been treated with contempt by previous writers. (When I visited the Peruvian Amazon region 20 years ago, I was warned never to use this term, as it was considered highly derogatory.)

His portrait of Dona Cabocla, an indomitable mother of eight children, six of whom have survived, and a kind of femme savante of the forest, is unforgettable:

She was a little over five feet tall and as lean as a stick. A red hibiscus was folded into her long gray hair, fastened with a frayed blue toothbrush as a barrette. Her expression was slack, almost sorrowful; she had a furrowed, aquiline nose, down turned lips, and eyes that seemed worn out by what they’d seen. But when she spoke, Dona Cabocla looked at you straight on with a piercing intelligence. She practically sang, gesticulating with long crooked fingers, and would clap her hands and exclaim “Oh! Meu Deus!” as if anything worth saying should be said voluptuously or not at all.

Sometimes Mr. Campbell’s extraordinary descriptions border on the vertiginous. He not only possesses a microscopic eye for detail but has the somewhat scary knack of bringing all these details into hallucinatory collision. Thus, in discussing the multitude of pests that descend on his team, he can write:

Listen to the bees. I have become the dinner of every bee, chigger, mosquito, tick, and biting fly that has evolved to suck the juices of the creatures that live in this forest. My nutrients are flying and buzzing everywhere in this forest and will soon be passed on in humble, hopeful eggs. The calcium atom that yesterday resided in the capillary wall of my finger is now depolarizing a neuron in the brain of a mosquito, enabling her to avoid my slap.

Mr. Campbell exhibits a rare joy in words on every page of this book; not only in such arresting phrases as “humble, hopeful eggs” (I wish I could keep that in mind when being mosquito-ravaged!) but vivid Portuguese expressions, words drawn from Indian languages, and a daunting array of biological technical terms. He provides a glossary of the Portuguese but not of the biologese; still, it doesn’t spoil the liveliness or the pace of his narrative. Most of these terms can be inferred from the context, such as the word “amplexus” (not to be found, by the way, even in the second edition of the Oxford English Dictionary), which becomes immediately clear.

A certain species of Amazonian tortoise loves the “maggoty orange” fruit of the abiu trees:

[A]ll one has to do is wait beneath the mother tree for the tortoises to appear. … Today three jabutis [the redfooted tortoise, Geochelone imbricata, according to the glossary], including a couple in amplexus, are gorging on the abiu, maggots and all. The male slides his long, hard tail under hers, straining and audibly groaning, while she eats demurely.

For all Mr. Campbell’s jubilance in nature and in the words nature inspires, this is a grim and dispiriting narrative. The destruction wrought on the Amazon region by the hand of man beggars description and prompts despair even in so robust a scientist as he. According to a recent conference on biodiversity held at McGill University this past May, the changes to the environment over the last half century have been the worst, and the most catastrophic, in human history; not only have fish stocks been reduced by 90%, but 12% of birds, 23% of mammals, and 32% of amphibians are now confronting extinction. To read this magisterial and heartbreaking book is to experience a sense of irremediable loss, not of symbols or of shadowy simulacra but of living, pulsing individual creatures in all their unimaginable variety.