The Naturalist’s Trance : IN SEARCH OF NATURE.<i> By E. O. Wilson (Island Press: $19.95, 192 pp.)</i>

Nature writing, as we know it, began in the late 18th century when Gilbert White, an English curate living in the village of Selborne, invented the naturalist’s essay with a series of formal but endearingly observant “Letters” addressed to two knowledgeable friends. This was about 200 years after Montaigne had fathered the form of the essay itself. And in America, Gilbert White’s contemporary, William Bartram, a botanist from Philadelphia exploring for specimens through the primeval South, composed his magnificently vivid “Travels,” published in 1791.

Modern science then entered the picture when brilliant generalists like Charles Darwin and his colleague and rival, Alfred Russell Wallace, wrote still-fresh accounts of their journeys and discoveries around the world--an inspiration radiating to more figures like Loren Eiseley (“The Immense Journey”) and Claude Levi-Strauss (“Tristes Tropiques”). “The Sad Tropics” was of course a prescient title, as the ravaging story of wholesale species extinction since Levi-Strauss’ travels in Brazil during the 1930s has proved.

Edward O. Wilson, born in 1929, is one of the world’s leading entomologists, the originator and virtual avatar of the new tangent of inquiry called sociobiology and twice a Pulitzer prize winner. In this latter stage of his career he has added activism to the proud tradition of the brilliant generalist, winning a special position of honor by leading the struggle among his scientific colleagues to preserve creation, or worldwide biodiversity, as it is sometimes called. His range of learning and the grip of his involvement have been extraordinary, even heroic. A shy man--vilified not many years ago by a misreading of “Sociobiology” as being soulless and mechanistic--Wilson has been tireless as an editor (“Biodiversity”), author (“Biophilia”) and organizer on behalf of emergency measures of conservation, especially for the tropical rain forests, where half of all life forms live.

“In Search of Nature” amounts to a kind of precis of decades of work, encapsulating his boyhood passion for catching snakes (I share this: Shall we call it ophidophilia?), the close study of ant genera that has constituted his central thrust and the sociobiology that brought him notoriety and fame and may have been his most original intellectual contribution along the way.

It is also the source of ripened metaphors with which, lately, he exhorts us to save ourselves from beaching “upon alien shores like a great confused pod of pilot whales.” Man has “become a geophysical force,” “an environmental hazard.” “The environmentalist vision sees humanity entering a bottleneck unique in history,” he says. In the essay “Systematics Ascending,” he issues a cry to action to his fellow taxonomists and other specialists: “The time has come for systematics to move on, to meet its destiny. Otherwise, why was all the work done?” What has already been discovered “generates a sense of the sacredness of place and of life . . . the long and enchanted roster.” He asks them to draw from their “deep expertise in particular groups of organisms” a “freewheeling opportunism in the choice of problems” to plumb to find solutions that may save what they have studied.

The vast majority of species that are disappearing (a minimum of three per hour from the rain forest alone, he estimates) have never been examined by a scientist at all. Their potential “values” die with them undiscovered. What is needed is a pluralism among scientists, linking and diversifying individual projects of research, as well as an immense and primary change of emphasis on the part of society as a whole. Following each of the five previous “extinction spasms” in the past 500 million years, life required at least 10 million years of natural evolution to recover. (The last was at the close of the Mesozoic era, 66 million years go, after perhaps a collision of an asteroid with the Earth ended the Age of Reptiles.) But we are also destroying the habitat necessary for even that span of recovery.

The essay “In the Company of Ants” has a pell-mell zest, a rushing enthusiasm, a happy surf of facts and figures, not marshaled like a zoologist’s brief but with the love that makes him gush elsewhere that ants are “more wonderful than a rhinoceros.” People ask him, as a world authority, what to do about the ants in their kitchen. “Watch where you step,” he says. Be careful of little lives. Feed them crumbs of coffeecake and get a magnifying glass and you will be as near “as any person may ever come to seeing social life as it might evolve on another planet.” Six hundred million years separates their line of social development from ours.

“The naturalist’s trance” is how he describes the absorption those who love nature fall into, when observant (though a 5-foot water moccasin in Brewton, Ala., almost terminated his career before it started, he says). Biophilia is our innate emotional affiliation with other creatures. And through it we can reach some feel for “deep history,” which is another one of Wilson’s signature terms. Homo sapiens’ history alone extends back for a half-million years and is imprinted in us in scarcely fathomed hieroglyphics, not to mention possible formative influences before that.

Self-exploration of this sort should be exuberant as well as verging on our sense of what is sacred. And Wilson is a writer of enthralling importance for our place in time.