“Puke,” one suspects, is one of those monosyllabic Anglo-Saxonisms in which a John Donne scholar may be relied upon to avoid trafficking except in the greatest extremity.

And, although playwright Margaret Edson will push the acerbic academic heroine of Wit to situations even more extreme than the one that evokes the word, the scene in which “puke” turns up is but one of several indelible passages in an unforgettable work of theater.

It’s not so much that the stage picture is striking, though that it certainly is: Dr. Vivian Bearing (Judith Light) retches uncontrollably into one of those green plastic hospital basins, her thin and thinly gowned frame twisting and arching in one violent convulsion after another. Rather, it is that this is a moment both immensely theatrical and intimately, pathetically human, and, as such, it is the very distillation of both this astonishing play and the performance that illuminates it in the touring production now at the Kennedy Center. That the actress handles it with enormous confidence is reason enough to cheer; that the author chooses to punctuate the scene with a wry, reflexive comment on language is enough to make a theater lover laugh for joy.

High priestess of an arcane literary discipline, Dr. Bearing finds herself brought low by her subject’s medical analogue, a cancer so insidious and complex and incomprehensible that her doctors’ only answer is to treat it with an experimental regimen that will kill her itself if the rapidly branching tumor doesn’t. She has become to them what esoteric texts have been to her: an experiment, an opportunity for data harvesting, a subject to be mastered. What she brings to the inquiry are the tools she has so ably employed in her rigorous life of the mind: fortitude, pride, rapacious curiosity—and, of course, a terrifying wit.

“If I actually did barf my brains out, it would be a great loss to my discipline,” Light’s Dr. Bearing remarks after that bout of vomiting, her ironic tone belying the slight tremble of her hands. “First my colleagues, most of whom are my former students, would scramble madly for my position. Then their consciences would flare up, so to honor my memory they would put together a collection of their essays about John Donne. The volume would begin with a warm introduction, capturing my most endearing qualities. It would be short. But sweet.”

The truth, it will have become obvious, is that Dr. Bearing is anything but sweet. She is, rather, the sort of intimidatingly intelligent academic whose unyielding pursuit of enlightenment has so consumed her life that there has been no room left in it for human connections: No one visits her in the anonymous medical facility she inhabits on the Eisenhower Theater stage, and Edson’s script makes a point of letting you know there’s no one in her life who might reasonably be expected to. Fierce of mien and quick with a withering one-liner, she is not the kind of professor who wants her students to like her. “I am, in short, a force,” she notes without apology in one of the direct audience addresses that help keep Edson’s play from veering too far toward melodrama; for exercise, “I pace.” (That last phrase, delivered in a sort of clipped roar, is just one answer in a rapid-fire medical interview that’s so much more hilarious onstage than on the page that there’s no point in trying to capture it here.)

For all her isolation, Bearing is not a figure to inspire pity. If Edson takes care to show the character’s dawning awareness of her impoverished emotional life, she suggests as well that perhaps the consolations of a profound commitment to Donne’s poetry, the rewards of any devotion as pure and uncompromising as Dr. Bearing’s, may be substitute enough. It has, if nothing else, provided this remarkable woman with the fortitude to face an ignoble end with tremendous nobility—something all too few of us can hope to muster.

Self-consciously infatuated with the power of language and fascinated with the human response—both intellectual and emotional—to suffering and doubt, and the inescapable reality of death, Edson’s 90-minute script is at once a brilliantly spare theatrical artifact and a headily complex text. The playwright delights in riffs on the vocabulary of medicine and literature even as she confidently proposes answers to eternal questions about the human spirit. The painful scenes that chronicle Dr. Bearing’s rapid decline—and the indignities visited upon her in the name of medicine—are bracketed consistently with her sardonic commentaries on them; she can’t help deconstructing the narrative, distancing herself (and the audience) from its pathos, analyzing and critiquing the story until finally its momentum catches her up and carries her, still resisting, to its inevitable conclusion.

Wit is not a perfect play, though—a device that subjects Dr. Bearing to the brusque ministrations of a former student seems too neat a construction to be entirely satisfying—and it is less than perfectly produced here, though Light’s performance in the lead role is certainly a redoubtable one. Head shaved, feet bare, she’s a steely ascetic amid the antiseptic atmosphere conjured by the swishing hospital curtains and rattling gurneys of Myung Hee Cho’s spare design; Light commands the scene utterly, even as her grip on that ever-present IV pole tightens, as her gait becomes more labored, as the progressively harsher angles and whiter tones of Michael Chybowski’s eloquent lighting scheme frame her features in increasingly stark lines. Individual responses to the details of her performance will differ—a friend, firmly braced against the play’s manipulations, found actorish mannerisms in certain of its particulars—but Light’s performance struck me as wholly committed, surprisingly unselfconscious, and entirely convincing, the only unalloyed triumph of the production.

Few of the other actors can even hold the audience’s focus, though, especially because Light’s Dr. Bearing is, except for momentary intervals behind a semi-opaque curtain, never out of the line of sight during the intermissionless evening. Daniel Sarnelli is remarkably one-note and obvious as Jason, the oncology fellow, whose focus on research results at the expense of humanity is so obviously meant to shock Dr. Bearing into understanding the implications of her own scholarly ruthlessness. Lisa Tharps and Diane Kagan give warm but not especially well-rounded performances as a caring nurse and Bearing’s wise mentor, respectively, though the trouble may be that Edson hasn’t quite written complete characters for them.

No matter. The fierce, uncompromising figure at the center of Wit is character enough for a score of plays. In Vivian Bearing’s fearless march to the threshold of the next world, a bracingly intelligent, marvelously humane playwright has a thing or two to tell us about the paths we choose to walk in this one. CP