A toe becomes a monster. A chicken's egg transforms itself into an ivory-backed mirror, a pool, a man's bald head. The sensual, irrational poetry that pulses beneath reality's smooth skin drenches "L'Amour fou: Photography and Surrealism," which goes on view today at the Corcoran Gallery of Art. This is -- to use a word the Surrealists used often -- a marvelous exhibit. It is blasphemous, provocative, erotic and amusing. And it is murderous as well.

Painting is its victim. The famous canvases of Salvador Dali, of Max Ernst and Rene' Magritte -- those icons of Surrealism enthroned in the textbooks -- are withered and then overcome by the 281 mostly unfamiliar camera-made objects assembled for this show.

They make Surrealism's paintings seem overcautious, overpolished, calculated, bland -- as if those far-too-careful masters of the brush had surrendered to the rational and closed themselves to chance.

Manipulating brushes is close, laborious work that smothers spontaneity, that inevitably relies on stiff premeditation. In the very act of painting, Dali and Magritte stepped back from the surreal, from the parallel reality that the ordinary hides. They left us, at the best, only secondhand records of their dreams. In the photographs on view -- by Man Ray and Jacques-Andre' Boiffard, by Hans Bellmer and Brassai , and others less well known -- we see the dreams themselves.

It is astonishing to learn that the present exhibition is the first one of its kind. Rosalind Krauss and the Corcoran's Jane Livingston, who put this show together, have here upset a hierarchy long accepted blindly. Their argument convinces. It is not Surrealist painting, nor Surrealist sculpture, but Surrealist photography that most compellingly reveals the movement's contribution to the visual arts.

The Dadaists, who went before, had indulged in wild non-sense, in anarchy, in play. The play of the Surrealists is often deadly serious, earnest, almost scientific. Like Freud, who taught that dreams reveal the unconscious, the Surrealists believed that common objects -- an egg, a mirror, a sewing machine, a breast -- revealed something higher. They taught themselves to see the enigmatic, the supressed -- the extraordinary hidden in ordinary things.

Objects were but triggers. The rational was blind. To glimpse the strangeness of poetic truth required abandonment of logic and submission to desire. The Surrealists admired the Marquis de Sade, who wholeheartedly indulged his lusts -- and the 19th-century poet Isadore Ducasse, who called himself Count Lautre'amont and had written of the beauty of "the chance encounter, on an operating table, of a sewing machine and an umbrella" -- and Pol Roux, the Symbolist writer, who, each night before he went to bed, posted on his bedroom door the sign "Poet Working."

Andre' Breton, the Surrealist "Pope," had called for an art founded on "pure psychic automatism," on unplanned puns, on games of chance, on automatic writing. Another Surrealist technique -- one that helped produce many of the finest photographs displayed -- was the unplanned wandering, half sleeping, half awake, of the city's streets. It was essential to be open to surreal visitations. Like Picasso, who made sculptures of found objects, the Surrealist photographers made visual poems of found signs.

Once you learned to see them, as Brassai did early on, you found them everywhere, in scratches on the pavement, in graffiti on the wall. A number of his photographs from the early 1930s (almost all the objects in this show were made between the wars) portray those small but loaded things that he chose to call "Involuntary Sculptures" -- a theater ticket stub discovered rolled into a cylinder in the bottom of one's pocket, a kneaded eraser, a bit of half-chewed bread. It is the photograph that drives these mundanities toward poetry. That ticket stub, afloat on glass, becomes a kind of rocket; that half-chewed roll, while clearly made of bread, becomes a sign of sex.

We see and yet we don't see; we find in what we understand something wholly strange. A pair of shoes placed on the stairs, and photographed in 1949 by Marcel Marie n, becomes a portrait of an absent being. 1949 Raoul Ubac photographs a model reflected -- and half-eaten -- by the poorly silvered glass of a ruined mirror. She, too, seems a shade. This show is filled with ghosts.

It is also filled with dreams. For while we easily accept the fiction that is painting, photographs look real. They suspend our disbelief. We buy the truths they sell us, though those truths are made surreal here by a variety of means -- by double exposures, for example, or the heating of the negative. All tricks are permissible. Andre' Kerte'sz will pose his nudes before distorting fun-house mirrors. Rene' Magritte will employ collage, mysteriously transporting the Baroque Paris Opera to a Barbizon School landscape of ponds and grazing cows. Man Ray, in his "Rayographs," will place various objects -- an eyeglass lens, a gyroscope, a feather -- on photo-sensitive paper he exposes to the sun.

A number of these photographs -- and some of the most disturbing -- are absolutely straight. In a picture by Raoul Ubac of 1935, a piece of raw, wet liver hangs from a model's mouth. In 1933, Man Ray photographs a nude whose upraised arms we read as horns, whose breasts we see as eyes, so that the torso is at once a woman and the horned head of a bull.

That eerie sense of doubling, of looking at an object that is both what it is and what it surely isn't, is sensed throughout this show.

So is male love, and male lust. The exhibition is filled with nudes and erotic fetishes photographed from unexpected angles, or in distorting mirrors, or stroked by shadows or by sun. Some of the images on view, Hans Bellmer's, for example, approach hard-core pornography (the Surrealists, like the Dadaists, were not afraid to shock). But others here are sweeter. Lee Miller, herself a Surrealist photographer, was for a while Man Ray's lover. She could hardly be more beautiful. The portraits that he made of her feel like hymns of love.

Something free, lighthearted, energizes many of the images displayed. Photographs are cheap, and many here were made less as costly objects than as almost casual illustrations for Surrealist magazines. Too much seriousness, it seems, binds one to the real.

And diminishes the exhibition's otherwise first-rate catalogue. Krauss' thoughtful essays for example, while loaded with references to Jacques Derrida, Walter Benjamin, Louis Aragon, Roland Barthes and other heavy thinkers nowadays in vogue, are wholly devoid of humor. One feels she somehow missed the point. This surprisingly accessible, often naughty show is filled with shocks and laughs.

You won't get in unless you pay. Admission for adults is $1.50. "L'Amour fou" (the phrase "mad love" is a quote from Breton) has been beautifully installed by Alex and Caroline Castro, who also designed the catalogue. This important show will travel to San Francisco, Paris and London after closing here Nov. 17.