WHEN EMILY MANN'S PRODUCTION of Robert Montgomery's Subject to Fits becomes good theater, and good art, the Loeb stage is set spinning with the whirl of a dance of living death. All of the characters in this "response to Dostoyevski's The Idiot" are trapped in individual hells, and in the bigger hell of the universe, and when they are forced to test their limits and laugh at them, human strength has a chance to win a sane survival. In morbid party games, in psychic tortures gleefully inflicted and returned, Mann's and Montgomery's cast of depraved and normal 19th century Russians exploit the full resources of their cramped natures, from their inbred manners and movements to their neurotically sharpened perceptions of miniscule events. At times their passions fill the theater.

Unfortunately, the play is Montgomery's first work, perhaps autobiographical and certainly immature; it doesn't build to any resolution of crises, only defines the forces it presents more clearly as the evening progresses. What Montgomery dramatizes are his characters' most heightened psychological confrontations, particularly as they affect his Prince Myshkin--a bloodhound who seeks out people's torments, not their persons; a self-deceived martyr hoping to relieve the suffering of mankind while he seems to further it. Montgomery creates a sexual triangle among the coarse Rogochin, the passionate, misused and vengeful Natasha, and the sexless Myshkin, undercutting any examination of either problems, and throwing the focus on the Prince's inability to get it up rather than his inability to assert his gentle values in a morally chaotic atmosphere. He also doubts the ability of anyone conscious of existential loneliness to hold a consistent moral vision, since this ridiculous assumption comes out only in isolated rhetorical interludes, it is best forgotten.

But if Montgomery trendies out and muddles his abstractions, he has at least had the sense to depict the concrete human characteristics of the trio's surrounding presences--the grasping mediocre manservant. Ganya Ivoglin, his drunkard father and consumptive brother, the soft headed but sweethearted Madame Yepanchin with her sheltered virgin of a daughter; and Lebedev, a disgustingly, dissipated opportunist and hanger-on who has left his family behind him and come to St. Petersburg to find a master who will leash him. Let these come into the action and the audience senses a full, real context (though their actions and dialogue are as stylized as those of the other three.)

MANN STICKS CLOSELY to Montgomery's scenario, and sends it off with the balletic theatrics and vivid emotionalism needed to give it effect. The entire play is enacted on a stage base except for a canvas-sectioned backdrop behind which white figures rhythmically evoke the contortions of the Idiot's mind, and a series of ramps, stairs and platforms which provide as many stages within the stage as the situations demand. Mann uses this excellent Peter Agoos set (he also did the costumes) to help us keep track of all the characters' forward motion without upsetting the fluidity of the action. She has done fine things while pulling the Idiot from one trauma to another, lining up three-quarters of the cast to chart their reactions to the consumptive's incipient suicide while the General chews his ear off, and finally letting the consumptive show the General and the Prince his ass before the lights fade. Her lighting cues, for the most part well executed by lighting director Thomas Parry, keep audience attention drawn to the right play areas, and the breaks into song and dance are managed well both by the cast and the orchestra (Dennis Crowley conducted and David Fechtor choreographed; the music itself sounds like something out of horror movies). If occasionally Mann underlines a situation where it isn't necessary (the Prince's tentative steps of love towards Natasha when he sings his proposal to her reminded me of the worst of West Side Story), she has on the whole brought off an incredibly complicated production with both grace and force.

Though I have several reservations about some major characters, the acting is consistently good. Of the toplined trio, Marianna Houston's Natasha is the most achieved; she has the best-written part, and takes advantage of it with the confident sweep of her broadest gestures and the intent restraint of her quiet moments. Christopher Joseph's Rogozhin is often caught between a swagger and a simper, and his rasping voice occasionally cracks, but his part is that of a hard on personified to both sexes, and I can't imagine how else he'd be able to play it as written. Bernard Holmberg's Idiot is sufficiently strong to hold the production together, keeping the lid on a certain hermaphroditic unctuousness which is inherent in the role; and he does toss a mean epileptic fit.

THE SUPPORTING CAST has, in human terms, the juiciest roles--and takes full advantage. Tony Abatemarco's General Ivolgin, Michael Gury as his healthy and Jack Gilpin his tubercular sons are effective both singly and as a divided family, just as Geralyn Williams and Eleanor Lindsay, Madamae Yepenchin and Aglaya, form anice bourgeois setpiece Josh Rubins is hilarious and vile as the obnoxious Lebedev.

Still I can't recommend the show to general audiences. For once the gap lies between a director's excellent execution and a playwright's silly intentions-which even skill can't totally transform. But those interested in theater put together by people who take the kind of chances which may one day produce meaning as well as excitement should see Subject to Fits for its moments of passion and promose.