Changing a Brutal Game.

The game of football was still going through fundamental change in the early years of the twentieth century. The game's brutality — eighteen collegiate players were killed in 1905 — caused President Theodore Roosevelt to threaten to outlaw the sport and led to new rules, such as the creation of a neutral zone between offensive and defensive lines, the increase of yardage required for a first down from five to ten yards, and the legalization of the forward pass. The changes did not stem the violence, though, as there were 113 fatalities between 1905 and 1910. In 1910 seven men were required on the line of scrimmage and such practices as the flying tackle, the interlocking of arms in running interference, and the pushing and pulling of the ball carrier to advance the ball were deemed illegal. Also, the football game was divided into four...