The artist Jacques de Gheyn II (1565-1629) knew the recipe for witch's ointment, a concoction brewed of Deadly Nightshade, Monk's Hood, rats and frogs and gobs of fat from unborn or unbaptized babies. But De Gheyn was a companion, too, of his country's most distinguished enlightened intellectuals, one of whom, Sir Constantijn Huygens (1596-1687), urged his artist friend -- "and the man certainly gave ear to this" -- to depict the strange new world observed through the eyepiece of the microscope, a wonderful device just recently developed.

De Gheyn (whose name rhymes with "divine") lived in changing times. His mind was partly modern, partly medieval. Though born into the Roman faith, he loyally and proudly served the Protestant prince of Orange. Part sorcerer, part scientist, part Calvinist, part Catholic, he was, there is no doubt, a man of many parts.

One hundred of his drawings go on view this morning in the National Gallery's East Building. "Most connoisseurs agree," observes J. Carter Brown, "that De Gheyn is the finest Netherlandish draftsman before Rembrandt." Collectors of old drawings, historians of Dutch art and others in the know admire his sheets enormously. Yet almost all the rest of us hardly know his name.

The gallery's exhibit, the first solo exhibition ever given to the artist, partially explains his relative obscurity. For the De Gheyn encounter here seems, at least at first glimpse, a dozen different men.

He made sweet domestic genre scenes of Dutch mothers and their children. And scary scenes of witches flying through the air. He made scientific studies of rare West Indian insects, fish from tropic waters, donkeys, frogs and birds -- and equally convincing images of monsters. He did a manual of arms for Holland's musketeers, and life drawings of nudes, and knowing illustrations of obscure saucy jokes. He drew somber crucifixions, and wild, wind-swept landscapes. He designed fantastic fountains wonderfully encrusted with larger-than-life lobsters, turtles, owls and serpents. He portrayed scientists (for instance the astronomer Tycho Brahe), and long-dead Roman heroes, and figures representing Wealth and Pride and Envy.

And when he changed his subject, he changed his style, too.

He worked in watercolor, pen and ink, silverpoint and chalk. His portraits of his friends are so detailed and lifelike they seem almost photographic. The how-to-do-it drawings for his manual of arms are completely unambiguous.

But his images of fiends busy at their work -- stirring boiling cauldrons or biting babies' necks -- are so smoky and so free that some scholars have suggested that De Gheyn was high on something, witches' brew perhaps, when he put these visions down.

His lovingly detailed scientific studies of reptiles and roses recall those of Durer. His sweet scenes of domesticity -- one here shows his little boy busy at his drawing book -- predict those of Rembrandt. (Jacques de Gheyn III, in fact, would once pose for that great master. The resulting portrait, though well known, has had a fate so strange that one might well suspect it had been somehow cursed: The painting, owned by the Dulwich Picture Gallery, is only rarely seen in that gallery near London, for it has been stolen on four separate occasions and, as of this writing, is missing once again.)

Today we tend to separate De Gheyn the close observer, peering through his lenses, from De Gheyn the fantasist. But De Gheyn himself observed no such division: He moved from one world to another, and back again, with ease, sometimes while composing on a single sheet.

One of the finest drawings here is described in the catalogue as "Two studies of a frog, one of a dragonfly, and one of an imaginary insect." The frog was surely drawn from life. The dragonfly beside it, with its tiny hairy legs and its four transparent wings, is also clearly seen. The deadpan catalogue suggests that less familiar creature at top left is "an unidentifiable winged insect reminiscent of a butterfly." But if you ever see a bug like that, it's time to rise and run.

True, it has four spotted wings, but they look like those of bats, and its head is bald and bulging, and it has a falcon's beak.

De Gheyn enjoyed portraying all sorts of ghastly beasts, skinned rats, for example, or wide-eyed just-skinned calf's heads dripping bright red blood, or ducks with broken necks. "Studies of attributes and creatures of witchcraft," one drawing here from Paris, shows a human skull, an open book of magic (one can tell it is a magic book from the hand with outstretched fingers pictured on its pages: "The showing of this stopped the uninitiated in their tracks"), and what seems to be a frog. But frogs like that, thank goodness, have not yet been seen. For growing from its bony chest are four hag-like breasts.

Often, when he drew from life, De Gheyn gave his nature studies an aura of the nightmare. The frog portrayed four times on one first-rate drawing here from the Rijksmuseum, Amsterdam, has hands much like a human's and a laughing, gaping mouth. The drawing of an oak tree from the Museum Boymans-van Beuningen, Rotterdam, shows more than just an oak: its bark appears to drip; its thick roots call to mind reptiles with eyes. "Two studies of a Porcupine Fish (Diodon hystrix)," from the same museum, offers no inventions, but then that eerie creature, with its open mouth and spines, must have struck the artist as monstrous enough.

The blowfish that he sketched was one of the specimens in the natural history collection of the Ambulacrum at the University of Leiden. A strange museum, that one. In addition to a number of botanical, zoological and ethnographic objects, it owned, by 1600, a number of mysterious things -- a mermaid's skin, for instance, a feather from a phoenix, and a griffin's leg.

De Gheyn was well regarded by the intellectuals at Leiden. Some were studying telescopes and lenses and the laws of optics; others were examining the unfamiliar plants, animals and artifacts that Holland's many sailors had brought home from their travels. Still others were exploring the magic of the past.

One subject of their scholarly investigations was the so-called "trial by water," which was one way of detecting the presence of a witch: The suspect, first bound hand and foot, was thrown into the water. "If he or she sank, i.e. drowned," the catalogue explains, "this was a sign of innocence, whereas floating was proof of guilt, for devils and witches were thought to be weightless."

To modern minds that sort of test may seem a bit unfair, and the committee of Leiden scholars who, at the request of the Court of Holland, investigated its efficacy in 1594 on the whole agreed. They "produced a negative verdict on its value as evidence."

De Gheyn, who as a young man had apprenticed to the artist Hendrick Goltzius (a man who dabbled in alchemy), and who later on had studied the magic of the gypsies (gypsies appear often in the drawings in this show), surely must have paid particular attention to the committee's deliberations. The black magic of the witches was his field after all.

bat16 Nowadays we tend to think of Dutch art in terms of bowls of flowers and meticulously depicted scenes of bourgeois life. But Holland is a northern land whose mists, like those of Germany, Scandinavia and Scotland, stir with other-worldly things. Though Rembrandt and his followers in the age of the enlightenment were blind to their appearances, De Gheyn, a more old-fashioned man, still saw the bats and devils that twitch throughout this show.

That rose (from the Staatliche Museen, Berlin) is more than just a rose: its perfume is unnatural, its sharp thorns call to mind Sleeping Beauty's sleep.

In one handsome sheet from Amsterdam, a plump woman, no longer young, is snoozing in an armchair. Her modest clothes suggest late 16th-century Holland; she wears a ruff around her neck and a small lace cap. Rembrandt drew her cousins time and again. But in the De Gheyn drawing she is not alone. The skeleton of Death whispers in her ear. His gesture appears almost tender -- until one sees that he is plunging a knife into her head.

Throughout the exhibition one feels that ghostly tension. A new way of seeing, scientific, rational and meticulously observant, is coming into being. But the old world, with its hag-frogs and devils, is still hanging on.

The show, eight years in preparation, was jointly organized by Andrew Robison of the National Gallery and A.W.F. Meij, curator of drawings at the Museum Boymans-van Beuningen, Rotterdam. (A drawing by De Gheyn was the first sheet that Robison acquired for his new employers when he joined the gallery staff in 1973.) It is a scholarly exhibit, modestly installed (and for that we should be thankful: the last thing the overcrowded gallery now needs is another flashy, crowd-attracting blockbuster exhibit). "The Drawings of Jacques de Gheyn" closes May 11.