A special collection for the incredible Metropolitan

What an incredible place the Metropolitan Museum is! I've visited it regularly for 28 years (or roughly 1,800 times), and I still cannot get enough of it. There are so many rooms and corridors, so many nooks and crannies containing objects I have never seen or really looked at. And to top it off, the museum keeps building new additions, opening new wings, and setting aside more and more galleries for special collections.

The latest such collection to be given a home at the Metropolitan is the one assembled by Jack and Belle Linsky and recently donated by Mrs. Linsky.

It is a most welcome addition, both for the quality of its contents and its enrichment of the museum's holdings in certain specialized areas. According to Philippe de Montebello, the Metropolitan's director, ''This ranks as one of the truly outstanding gifts and takes its place alongside the greatest collections ever given to this museum. . . . The level of quality is superb and includes many consummate masterpieces which give a new dimension or heightened character to the museum's holdings. From this point on, no publication of selected masterpieces of the Metropolitan can be produced without substantial reference to the Linsky Collection.''

The Linskeys preferred small, precious objects: Italian, French, German, Dutch, and Flemish cabinet pictures; medieval bronzes and enamels; Renaissance bronzes, jewels, goldsmith's work, and porcelains; and 18th-century furniture. Everything is first-rate and was chosen with great care. Particularly outstanding is the porcelain collection, which totals 229 pieces, and includes over a dozen Mennecy and St. Cloud chinoiserie and grotesque figures, rare pieces of Russian and Copenhagen porcelain, and some 30 Meissen figures and groups, including a series of J. J. Kandler's lively Italian Comedy characters.

For me, at least, the stars of the collection are a dozen or so of its paintings, most particularly Carlo Crivelli's ''Madonna and Child''; Fra Bartolomeo's ''Portrait of a Man''; ''The Adoration of the Magi,'' attributed to Gerard David;Gerard Ter Borch's ''The Van Moerkerken Family''; two tiny panels by Lucas Cranach the Elder; and Corneille De Lyon's tiny and exquisite ''Portrait of a Man.'' I was also intrigued by Rubens's small portrait of a man, the earliest known dated work by him.

The collection will be on permanent display in the Jack and Belle Linsky Galleries, which sit next to the Medieval Sculpture Hall on the main floor of the Metropolitan. Neo-Expressionist Rainer Fetting

Rainer Fetting is an international art-world celebrity, one of the very few Germany has produced in roughly 60 years. He is also one of the small band of European and American Neo-Expressionists, whose passionately painted and often luridly colored figurative canvases helped release painting from the formalist straitjacket it had worn for at least two decades.

All this took place in approximately the last three years, although Fetting's revolutionary art activities began a few years ago in Berlin when he helped bring Heftige Malerei (Vehement Painting) - an earlier version of Neo-Expressionism - into being.

He was then, and is now, one of the most interesting figures of this ''movement,'' partly because of the streak of unrestrained romanticism that runs through his work and tempers some of his more violent Expressionist outbursts, and partly because his imagery seems more authentically primal than that of most of his contemporaries.

The quality and importance of his art, however, are still in question, although he has, here and there, produced images of considerable power and strange, haunting effectiveness. Since most of his paintings have been inaccessible to American viewers, however, his reputation here has rested predominantly on articles, critical comments, and art-world gossip. The few canvases that have been seen in the United States have proved inconclusive, and a number have actually been quite bad.

Marlborough Gallery's recent exhibition of his paintings here has helped clarify the matter a little. It was an impressive show consisting of 17 large to huge canvases executed during the past year in Manhattan, where Fetting now lives. All were passionately direct in brushwork, color, and imagery, and most included old planks affixed to their surfaces. These generally rough-edged pieces of wood gave structural support to the compositions, helped define figures, or acted as framing devices. But mostly, they added an element of surprise and three-dimensionality that helped increase the various works' overall effect.

Only three or four of the pictures had any genuine staying power after the initial impact - or shock in some cases - had worn off. As is unfortunately true of so much Expressionist work, most if not all of the artist's energy and focus had gone toward capturing the viewer's attention, and little if any had gone toward holding it. Fetting shouts at us through his paintings, but then too often has little if anything to say when we respond. Because he is famous and fashionable, most of us will strain not to miss anything of significance, and even if we hear nothing, we'll probably give him the benefit of the doubt.

Only one painting, his monumental, three-panel ''West-Nacht,'' genuinely impressed me, and left me hopeful that his work will soon match his reputation. This canvas bears the stamp not only of art, but of major art, and indicates he may actually have something special up his sleeve.

I was also taken by ''Red Square Face'' and ''Blue Head,'' and found ''The White Wolf'' marred only by the animal's head. ''Holzbild (Mask),'' on the other hand, is silly beyond words, and represents Fetting at his weakest and worst.