'The Big Bang Theory' review: Bob Newhart takes them to school

THE SHOW "The Big Bang Theory"

WHEN | WHERE Thursday night at 8 on WCBS/2

WHAT IT'S ABOUT Professor Proton, aka Arthur Jeffries (Bob Newhart) -- who was Sheldon's (Jim Parsons) boyhood TV hero -- returns for a third time. But in "The Proton Resurgence," Leonard (Johnny Galecki) has to tell his pal some hard news: The professor has died. Sheldon, who cried when Kellogg's changed the design of the Raisin Bran box, seems to take the news with a surprising degree of calm, or maybe he's just fixated on the approaching "Star Wars Day." In any event, he falls asleep and dreams -- and in his dreams, he comes to terms with his infatuation, and grief. Proton first appeared last year in "The Proton Transmogrification," and then again later in "The Proton Displacement." We learned a few things about Proton: He's a bit embittered over his TV past; hates Bill Nye (the Science Guy); and is somewhat infatuated with Penny (Kaley Cuoco).

MY SAY One of the oversights of the Emmys -- and like Sinatra and regrets, it's had a few -- was the winner's circle exclusion of Bob Newhart until just last year, when he got a victory for best guest performance as Professor Proton. He had three straight nominations in the mid-'80s, but voters couldn't get him across the finish line, and so Newhart was going down in TV history as one of TV's great comic actors without an Emmy to prove it.

But the Proton win was more than a better-late-than-never consolation prize: In the past two outings, he schooled a whole new generation of viewers in the lost art of flawless timing, and how a silent beat (or two, or three) could work as effortlessly as the best-written quip or the sharpest retort. Leonard (in "Transmogrification") wonders, for example, whether Jeffries remembers sending him a signed photo years earlier. Proton: "I'll give you a hint (beat ... beat). I have a bracelet with my name on it."

Bob Newhart is 85 and one of the funniest, sharpest and -- above all -- most original talents in TV history. But he is 85, which does tend to make tomorrow's episode surprisingly poignant: Like Leonard, most people have a cherished Professor Proton in their past, and for many of them, that was Bob Newhart.

BOTTOM LINE Possibly, sadly, it's the end of this brief and memorable cameo. And, as before, Newhart makes it count.

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GRADE B+