As one of the greatest American poets of the 20th century, William Carlos Williams wrote hundreds of poems. As "Doc Williams," a general practitioner and pediatrician in Rutherford, N.J., he delivered hundreds of babies.

In time, Williams came to see the two as almost indistinguishable -- the babies and the words, the patients and the poems.

"The physician enjoys a wonderful opportunity actually to witness the words being born," Williams wrote in his 1951 autobiography. "Their actual colors and shapes are laid before him carrying their tiny burdens which he is privileged to take into his care with their unspoiled newness. He may see the difficulty with which they have been born and what they are destined to do. No one else is present but the speaker and ourselves, we have been the words' very parents.

"Nothing is more moving."

Williams was not unique in his dual career. The Russian playwright and story writer Anton Chekhov looked upon "medicine as my lawful wife and literature as my mistress." More recently, Dr. David Hilfiker, author of "Healing the Wounds: A Physician Looks at his Work," said, "Doctoring is my roots; writing, my wings."

Other famous writers with training in medicine include satirist Francois Rabelais; political theorist John Locke; Sherlock Holmes' creator Arthur Conan Doyle; poets Percy Bysshe Shelley, John Keats and Robinson Jeffers; and novelists Gertrude Stein, Somerset Maugham, James Joyce and Walker Percy.

What do medicine and art have in common that they have intertwined in so many lives?

"Looking and listening -- listening and looking," said Dr. John H. Stone, a cardiologist and professor of medicine, associate dean and director of admissions at Emory University School of Medicine in Atlanta.

And a poet. Stone has published three volumes of poetry, the last two being the only books of poetry ever reviewed in The New England Journal of Medicine. Some of the poems in Stone's most recent book, "Renaming the Streets," were originally published in an unlikely mix of magazines including the Annals of Internal Medicine, Chattahoochee Review, Patterns of Poetry and the Journal of the American Medical Association.

Joined by other writers, painters and musicians, Stone spoke recently at a conference on "Medicine & The Arts: Two Faces of Humanity," held in honor of the 150th anniversary of the National Library of Medicine.

In introducing the day-long conference, library director Dr. Donald Lindberg said the association between medicine and the arts is "so ancient, so persisting and so profound that we almost don't question it."

He acknowledged that "we have among us one naysayer" -- Hippocrates, the father of medicine, who counseled his followers to "at least avoid all citations of the poets, for to quote them argues feeble industry."

But if there was a muse at the Library of Medicine conference, it was not Hippocrates but Apollo, the Greek god of medicine, music and poetry.

"The arts and sciences are two sides of the same coin," said Dr. Arthur M. Sackler, a psychiatrist, researcher, publisher, art collector and philanthropist. "The arts are passions pursued with discipline, and the sciences are disciplines pursued passionately."

"Medicine preserves life; the arts celebrate life," Sackler added. "The masterworks of both proclaim our faith."

Poet Stone, 50, began writing verse in high school, then gave it up for lack of time during his medical training.

"The poems were there, just not being written down," he said, adding that the first poem he wrote when he took up writing again was about the cadaver he studied in medical school.

At Emory, Stone teaches a course in literature and medicine, in which medical students are asked to read such works as Kafka's "Metamorphosis" and Camus' "The Plague."

Works of literature not only teach students how to think metaphorically, Stone said, but also offer "an opportunity for ethical reflection" and a "sort of in vitro testing out" of the language of the doctor-patient relationship.

"It's much easier to discuss a novel than it is our own lives," Stone said, "but finally we end up discussing our own lives."

And for both writer and reader, literature "can be a force for sanity in our lives."

One of Stone's longer poems, "Gaudeamus Igitur" ("Therefore Let Us Rejoice"), was written as a graduation address to medical students at Emory. It reads in part:

For you will not be Solomon but you will be asked the question nevertheless

For after you learn what to do, how and when to do it the question will be whether

For there will be addiction: whiskey, tobacco, love

For they will be difficult to cure

For you yourself will pass the kidney stone of pain and be joyful

For this is the end of examinations

For this is the beginning of testing

For Death will give the final examination and everyone will pass . . .

For there will be hard data and they will be hard to understand

For the trivial will trap you and the important escape you

For the Committee will be unable to resolve the question

For there will be the arts and some will call them soft data whereas in fact they are the hard data by which our lives are lived

The connection between medicine and the arts is obvious to some, surprising to others. In his book-length poem "Paterson," Williams described how neighbors and patients reacted upon finding out he was a poet. A typical response to a poem: "Geeze, Doc, I guess it's all right but what the hell does it mean?"

Not many physician-writers can find the time and energy to keep up a full-time medical practice, as Williams did. They cut back, or retire.

"What happens to a retired surgeon is mysterious," said Dr. Richard A. Selzer, assistant professor of surgery at Yale University School of Medicine and author of "Confessions of a Knife" and other books.

Last spring, shortly after giving up surgery at age 56 to teach and write full time, Selzer received a telephone call from the chief ranger of Yellowstone National Park. The ranger asked Selzer to come teach at the Yellowstone ranger school "and tell us what the park really looks like."

"There must be some mistake," Selzer told the ranger. "My feet have rarely left pavement."

But it was no mistake, and last June city-slicker Selzer found himself tramping around the wilds of Yellowstone National Park with a bunch of Smoky the Bear types, studying elk tracks and rabbit scat. His appointed role was "to interpret the park as a human body."

Of one ranger, expert at identifying animals by their tracks and droppings, Selzer wrote in his journal: "About feces, he is as clinical as a gastroenterologist."

The journal also includes a harrowing account of a coyote attack on an elk calf, which Selzer read at the conference, punctuating it with this cryptic comment: "If you think that was about anything but medicine, you're mistaken."

Selzer also read a short story whose writing was inspired by something he saw through a doorway while on rounds at the hospital. It was a very old woman, near death and weighing not more than 70 pounds, "her hands like spiders on the ends of sticks," trying to thread an earring through her earlobe.

"The sight of that brave act of adornment touched me and became imprinted on my imagination," Selzer said.

Physicians write for the same reasons as other writers do, said Anne Hudson Jones, associate professor of literature and medicine at the Institute for Medical Humanities at the University of Texas at Galveston. But medicine offers them extraordinary opportunities for observing the human condition.

In an autobiographical essay called "The Practice," Williams wrote that medicine, far from interfering with his writing, was "the very thing which made it possible for me to write. Was I not interested in man? There the thing was, right in front of me." Literature and medicine "share themes of illness, suffering and death," said Jones, who also edits the journal Literature and Medicine.

"We hope, by teaching literature to medical students, that we'll eventually make them better doctors, by which I mean doctors who take better care of their patients and better care of themselves," she said.

"The patient's body, as well as the patient's story and lab data, become a kind of text for interpretation."

Interpreting "the half-spoken words" of patients, Williams wrote, becomes the "occupation of the physician after a lifetime of careful listening."

In between seeing patients, "Doc Williams" would jot down phrases -- a remark, an image, a moment -- based on what he had seen or heard. Later, often in the middle of night after returning from a house call, he would turn them into poems.

"The girl who comes to me breathless, staggering into my office, in her underwear a still breathing infant, asking me to lock her mother out of the room; the man whose mind is gone -- all of them finally say the same thing. And then a new meaning begins to intervene," he wrote. "For under that language to which we have been listening all our lives a new, a more profound language, underlying all the dialectics offers itself.

"It is what they call poetry."