Reprinted from yesterday's late editions

As folkloric extravaganzas go, Slask, the Polish folk dance and song ensemble, which played to a spotty but appreciative house at Constitution Hall Wednesday night, deserves rather high marks, generally.

The troupe of 100 dancers, singers and musicians, founded in 1954, presents a decent variety of steps and regional flavorings; a nice span of anecdotal, humorous and sentimental material; plenty of acrobatic excitement in leaps, flips and spins; exquisitely embroidered costumes in handsome native designs; and singing and dancing of almost computerized efficiency.

Still, as with so many similar troupes from other lands, all the ersatz spontaneity and gush of Slask gets to be depressing after a while.

If you've seen and heard undoctored folk arts, as we in Washington often have thanks to the Smithsonian and other auspices, you know how much genuine spirt has been siphoned off in these processed stage versions. As matters stand, most such troupes bear the same relation to their folk roots as the Lone Ranger did to the American West.

One can't help but wonder if these shows wouldn't be just as diverting - more, perhaps - if the choreography were a little less machine-tooled, the musical arrangements less saccharine of gaiety not so frequent, and the whole production not as subject to freeze-dried formulae. If this were smack less of the souvenir stand, and retain more of the verve and piquancy in the first place, without any sacrifices of "entertainment value."