Vaudeville, or what passes for vaudeville these days, may not be dead, but a couple of troupers are ailing. Just before showtime at Lisner Auditorium Saturday night, it was announced that George Jessel and Jack Carter, the scheduled headliners of Roy Raydin's Vaudeville '79 Revue, would not appear due to illness. In keeping with the grand old tradition, however, the show went on . . . and on . . . and on.

It matters not that the revue's performers are to vaudeville what Ethel Merman is to disco. Some of the evening's entertainers could delight a crowd under any circumstances. For instance, the Ink Spots, who stretched their beautiful harmonies over a long medley of hits, sounded untouched by time. And Tiny Tim, wearing a crazy comic-book quilt of a tuxedo, was outrageously funny, bumping and grinding out "Do Ya Thing I'm Sexy" in what has to be the definitive version of that song.

But most of the other acts -- particularly Janice Harper, Lawrence Hilton Jacobs and the New Christy Minstrels -- sounded as if they came to town solely to plug either a new album or a hole in their tedious performances surely would have been cut short by the hook in the old days.