Molie re's "Tartuffe," one of the truly inspired comedies, is reduced to a lugubrious semblance of itself in the Eisenhower Theater, where a new version of the play, prepared by British dramatist Simon Gray, opened last night.

"Version" is indeed the operative word, because while the plot may still be more or less Molie re's and while the characters have some of the same preoccupations, Gray has thrown a dreary, self-flagellating aura over the proceedings. Acted as if to the rhythms of a dirge, this "Tartuffe" is so inwardly directed that nearly all the outward fun vanishes.

There is, of course, darkness aplenty lurking just under the surface of the original, which provoked cabals in 17th-century France and required the endorsement of no less than Louis XIV to still its enemies. The title character is a lascivious hypocrite--in Gray's words, "a man who looks at the world and says, 'This is a cesspool.' " By his saintly utterances and well-timed displays of breast-beating, Tartuffe has won not only the blind allegiance of a certain Orgon, but also lodging under his roof. When Orgon returns home from a trip, he shrugs off news of his wife's illness, but greets reports of Tartuffe's hearty appetite with a "poor man," dripping with commiseration. ("Poor man" actually becomes a leitmotif in Molie re's play, but Gray defuses the telling line by turning it repeatedly into a simple sigh.)

In his eagerness to curry heaven's favor, Orgon signs over the family fortune to Tartuffe, betrothes his daughter to him, betrays friends, banishes his son and very nearly offers up his wife's virtue. If the king himself didn't intervene in the end--and Gray has spun his own variation on that ending, too--who knows where the treachery would lead?

As with most good comedies, a case can certainly be made for the gravity of events. But Molie re himself has already made it. What is remarkable about the original is that its merriment strikes deep, that it maintains an antic spirit while exploring the perfidy of man, that it is pensive and playful simultaneously. In Molie re, a pratfall can have metaphysical implications, but it is still a pratfall--robust and unapologetically entertaining on its own terms. Emphasizing the dramatic shadows, as Gray and director Brian Bedford have done, doesn't result in a new perspective on the work. It merely results in a diminished masterpiece.

Molie re's ebullient verse has been replaced by hesitant prose, his vigorous good sense by bleak pessimism, his succinct wit by strained cracks. Molie re could trap the enduring essence of a flirt in a quick couplet. Gray's equivalent: "People used to say she could roll her eyes at two men at once. That's why she's got that squint." More importantly, Orgon (Barnard Hughes, his white hair brushed into Man of La Mancha tufts) is no longer a human whirlwind, spinning impulsively throughout the house. He's now an introspective dolt facing a middle-age crisis and yearning for the simple certainties of childhood. His brother-in-law Cleante (Fritz Weaver), that pillar of reason, has become the opposite of himself: a muddled thinker. The young lovers (Christine Andreas and Jeff Hayenga), who should burst with the very sap of springtime, are just sorry saps. Only Dorine, the maid (the wonderfully eccentric Barbara Byrne), evinces the kind of pluck that sends comedy hurtling forward.

Besides directing the production, Bedford took over the role of Tartuffe in mid-rehearsal. His performance is rather obviously malevolent and on occasion, downright plodding. Still, Bedford is not entirely off-base. With his cherubic cheeks bearing the trace of a 5 o'clock shadow, he looks a little like a grown-up Pigpen from "Peanuts," and the sallow traces of boyhood serve him well. Tartuffe is the one brooding presence in the play, a perverse angel, crafty even in silence.

However, Bedford's mistake as a director is to let that brooding spill over onto the other cast members. If Tartuffe is to be the calm, threatening eye of the storm, there must be a storm around him. But here, the other characters lapse into somber moods, their words trail off into emptiness, and a sense of futility drains them of their energy.

In the play's most celebrated scene, Tartuffe attempts to seduce Orgon's wife, Elmire (Carole Shelley), almost but not quite before his very eyes, since Orgon is hidden under a table. Molie re was borrowing gleefully from the salacious commedia dell'arte when he wrote it. But glee is totally missing in the scene as it is played in the Eisenhower--edged out by a growing desperation on Elmire's part as Tartuffe makes his lumbering advances. When Orgon finally pops out of his hiding place, there is no surprise, no wild turnabout, no caught-in-the-act contorting. As Tartuffe later says to Orgon, "I knew you were under there." That's Gray's line, not Molie re's. But if it adds another touch of deviousness to the character, it also indicates the sort of thinking that spoils comic coups.

The production is handsomely mounted, but the trimmings so far outclass the text that one begins to lament them as misspent effort. Jane Greenwood has costumed the players with sumptuous brocades and silks, although the colors, bowing to the tone of the text, favor the sober side of the palette. Robert Cothran has provided Orgon and his family with a richly paneled house worth conniving for, as Tartuffe does. And one cannot say, with such an assemblage of actors, that the Center hasn't made a bid for the best.

But only those totally unversed in Molie re will be able to watch this "Tartuffe" with less than a sinking feeling. Gray has labored over the psychological motivations of his characters. And the labor shows. There is precious little sunlight in this version, only gathering gloom. No explosions of exuberance, only the fallout of despair. A lot of Gray. Not much of Molie re.

TARTUFFE. Adapted by Simon Gray from the comedy by Molie re. Directed by Brian Bedford; scenery, Robert Cothran; costumes, Jane Greenwood; lighting, Martin Aronstein. With Brian Bedford, Barnard Hughes, Carole Shelley, Fritz Weaver, Christine Andreas, Barbara Byrne, Jeff Hayenga. At the Eisenhower Theater through May 29.