Here's some fly-weight research.
This photo is a promotion for the July 4, 1912 fight between Jim Flynn and Jack Johnson. Tommy Ryan, a retired middleweight champion, was Flynn's trainer until June 17, when he quit after an quarrel of unknown subject with promoter Jack Curley (NY Times June 18 1912, "Ryan Quits as Flynn's Trainer").
Where there's boxing, there's Vegas, right!!
Except that... this is Las Vegas, New Mexico. Did you know such a place existed? Back in 1912, this was THE Las Vegas. Our "what happens, stays in" Vegas was a year old and full of dude ranches.
To drum up publicity for their happening town, civicly minded hustlers put on the decidedly uncivilized 45 round July 4th bout...
In this corner........ weighing in at 212 pounds. The heavy-weight CHAMPEE-OHN of the WOOOOOORLD, the Galveston Giant -- Jack Joooooohnson! In this corner, weighing in at 193 pounds. Hailing from Pueblo, Colorado, the saddle-making CAPEEE-TOL of the WOOOOORLD, the F-aw-IREman -- Jim Flynnnnnn...
And guess what? You can watch three minutes on YouTube!
(quoting liberally from the July 5th New York Times)
At 1:58 Referee Smith breaks them up. "Stop that headbutting," he says. At 2:40 he wags his finger and says "Stop it or I'll disqualify you."
"The n*gger's holding me!" Flynn roared back. "He's holding me all the time. He's holding me like this," and he offered to illustrate on the referee. Smith evaded the blood-stained arms held toward him and waved the two men together again.
At 2:16 - it was in the eighth round - Flynn flung himself upward again. Smith jumped between them and warned him once more. "Next time you do it I'll disqualify you," but changed his mind, for it happened again and again in that round, and repeatedly in the ninth before the police took a hand at 3:26.
Through it all, the champion was smiling.