Jack is trying to grin, but you can sense him thinking," if you keep prodding me I'm going to lay you out."
Corbett was the original Ali. He did a lot of the same things. Moving around a lot, leaning back and ducking, clinching, firing fast punches, and he loved to talk smack and smile at his foes.
Corbett is being annoying? It looks to me as if he two guys like each other. Considering that Corbett was an old champion, I imagine Dempsey was perhaps thrilled to meet him. The most interesting facet of this film is that Corbett looks to be a bit taller than Dempsey.
Yes he tried to get his opponents goat and usually succeeded,his most notable failure being when he seconded Jeffries against Johnson, and Johnson had a topping rejoinder for everything he said.
You can see him talking pleasure vs a badly outmatched Peter Courtney below. Then on cue, Corbett knocks him out in the final frame. The below link ( I think round 1 of 6 ) shows Corbett flashing some defense, ducking Courtney's punches or blocking them with his arms or gloves. It's impressive even if Courtney's skills are not. They fought in a very small ring for filming purposes. On film in a larger ring, Corbett uses the full ring, and his feet to avoid the incoming too. Defense without clinching if you will. https://www.youtube.com/watch?v=gpDhbpmtpvo In and out of the ring, Corbett was a hot head and a bit of a punk. I agree with Ed, on Corbett's height. He's taller than listed, and looks to weight a bit more than listed.
You can tell they're having fun for the camera. Corbett looks bigger than Tunney too in their sparring film.
In the leadup to the Fitzsimmons fight, his people (Billy Delaney and Charley White) measured him at 6 feet and 1/4 inch. This ran in some articles on March 17, 1897.
I think Jack was using his own good nature, to put up with Corbett, who he could have surely squashed like a bug on the windshield. my dad went to his NY restaurant as a GI, Jack did not want to talk about himself, he wanted to talk about my dad, would not let him spend a cent. JACK DEMPSEY