On July 4,1929 A brawl breaks out in the 3rd inning of a game between the St. Paul Saints and the Minneapolis Millers in the American Association. The Millers’ Hughie McMullen grounds out to first base, and spikes P Huck Betts, who is covering the bag. Betts replies by firing the ball at McMullen’s head in retaliation, but misses him; however, reserve infielder Sam Bohne, who is coaching at first base, enters the fray by punching Betts, and both dugoutsempty and a free-for-all ensues. Reporter George Barton describes it as “the most vicious affair ever witnessed at Nicollet Park.”

Source

Baseball Reference July 4