Mark Morris is the latest of a long line of modern-dance choreographers invited to spice up the repertory of a traditional ballet company. His ``Drink to Me Only with Thine Eyes'' for American Ballet Theater surprised everyone at its debut here in New York by not being pretentiously avant-gardish. Morris's own company, which was at Brooklyn Academy of Music in May, is so determinedly trendy, so emphatically anti-heroic, I wondered how he could use ballet dancers at all, let alone stars like Mikhail Baryshnikov and Martine Von Hamel. ``Drink'' turns out to be Morris's least self-conscious, most attractive work in any medium. It's as if he'd had a latent affinity for ballet all along, and finally found himself in a position to use it legitimately. I'm not talking about Morris's ability to choreograph, which has never been in question, but about subtler matters of taste, attitude, and style.
What distinguishes Morris's work above all is his formalism. His dances are always based on whatever musical structures accompany them, and are primarily expositions of a predetermined vocabulary. For his own dancers, he imposes odd gestures or poses that suggest an iconography of some kind onto an earthbound, turned-in lower body, and chest and arms so unstressed as to seem habitually inexpressive. Often I've felt the vocabulary isn't interesting enough to bear the repetition and variation to which he subjects it, and his dances end up looking bombastic. Or they stick so literally to the music that they seem hermetic, precious.
``Drink'' is as formal as Morris's other work, but somehow it seems freer, airier, and altogether more gracious. Its score, Virgil Thomson's ``Etudes for Piano,'' is a terrific asset, because it's lean, modern, and hasn't been heard a million times. Michael Boriskin is seated center stage at the piano, and plays the first of the 13 etudes most of the way through before any dancer appears. At the last minute, a man walks across with a woman lying athwart in his upraised arms. Just before he reaches the other side, he lowers her to the level of his waist, and she shifts too, in some small way. So the look of the lift changes unexpectedly but without emphasis.
The whole ballet is surprising that way. It doesn't fix itself in big presentational blocks - so many dancers per musical number - the way most ballet-ballets do, or set the stars apart from lesser lights with ballet's usual fanfare. The dancers dash in and out so quickly and unpredictably that you hardly have time to identify them, let alone thrill to their antics, before they're replaced by others. It's an antidote to that kind of obvious, virtuosic showpiece, simultaneously demolishing and honoring the stodgy stand-there-and-dance-till-you-slay-'em formula.
The whole ballet has an air of playfulness that comes not from playful business or mugging, but from a rhythmic freedom and exuberance Morris seldom has shown before.