Bob Dylan is so old and weird and vocally ravaged that there's been muttering on the Internet and in more respectable quarters that the septuagenarian bard should bring the Never-Ending Tour to an end, and hang up his rock-and-roll shoes for good.

Balderdash. On Wednesday night, Dylan played the Mann Center for the Performing Arts in Fairmount Park. Sure, he often sounded like a dying bullfrog scat-singing difficult-to-decipher Bob Dylan songs. (Was that "Leopard-Skin Pillbox-Hat" he opened with, in a predictably unfamiliar arrangement? Indeed it was.)

And yes, when he stood stage center without an instrument and sang with arms extended while wearing a broad-brimmed white hat and black cowboy suit, he did look like a macabre cross between Maurice Chevalier and Vincent Price.

But when he was singing in a scorched-earth voice - and, sometimes, playing a keyboard you could actually hear, or blowing into a harmonica on "Tangled Up in Blue," or playing a tasty, surprisingly well-thought-out guitar solo on "Simple Twist of Fate" - he was singing incomparably great Bob Dylan songs.

More important, he sang the lyrics of a revamped "Desolation Row," a faithful-to-the-Chicago-blues-original "Beyond Here Lies Nothing," and a swaggering, rugged, despairing "Blind Willie McTell" - as if they were of importance to him.

Maybe not as much importance as they were to the devoted Dylanologists among the crowd of 6,000 or so, who were warmed up with a mildly ingratiating blues boogie-woogie opening set by Leon Russell, the 69-year-old pianist who was a vision of blinding whiteness in matching cowboy hat, shirt, and a Cousin Itt-style beard and hairdo that didn't appear to have been trimmed since "A Song for You" was recorded in 1970.

But if Dylan himself didn't sing as if ascribing as much meaning to every word as his reverent multigenerational followers do, his performance did counter a key line in one of his best latter-day songs - "I used to care, but things have changed," a disingenuous claim that adds up to "one big lie," to crib another line from "Things Have Changed."

Dylan has been acting blasé and pretending not to care since . . . I don't know, 1966 or so? But you don't keep on keepin' on as productively as he has in his senescence without investing a great deal of yourself in your work. Even in the case of songs that wearily claim, as Dylan did during "Mississippi" on Wednesday, that he has "Got nothing for you, had nothing before / Don't even have anything for myself anymore."

Skeptical fans who have grown weary of Never-Ending Tour dates and chose to sit this one out picked the wrong time to bail on Bob, who was engaged and frisky, increasingly so as the 90-minute evening wore on. And the nimble, up-for-anything band, which currently features Tony Garnier on bass, George Recile on drums, and, in their front man's elocution, "Stu Kimball on rhythm gee-tar, Donnie Herron on steel gee-tar, and Charlie Sexton on lead gee-tar," is as good as it's been in a decade.

And if you could understand only select lines as the singer scratched and moaned and bellowed his way through a revved-up and rumbling "Thunder on the Mountain," a powerfully doomy "Ballad of a Thin Man," or a boldly ringing, satisfying, sneering "Like a Rolling Stone," well, that was OK. Because you knew all the words anyway.