After the 1910 season, Hugh Fullerton, writing in “The American Magazine” said baseball had no universal language.
“Each team has its different system of coaching, its different language of signs, motions, cipher words, or phrases, and no one man can hope to learn them all.”
Fullerton said the “worst of trying to study” the signs of various clubs was trying to track when they changed:
“If Arlie Latham jumps into the air and screams ‘Hold your base!’ it may mean ‘Steal second,’ today and tomorrow it may mean ‘Hit and run.’ One never can tell what a sign means. Hughie Jennings hoists his right knee as high as his shoulder, pulls six blades of grass and Jim Delahanty bunts. You are certain that Jennings signaled him to sacrifice, so the next day when Ty Cobb is bat and Jennings goes through the same motions, you creep forward and Cobb hits the ball past you so fast you can’t see it.
“If Connie Mack tilts his hat over his eyes and Eddie Collins steals second as the next ball is pitched, naturally you watch the hat, and lo, Jack Barry plays hit and run. You hear Clark Griffith yelp ‘Watch his foot!’ and see two of his players start a double steal. The next time he yells ‘Watch his foot!’ you break your neck to cover the base, and both players stand still.”

Arlie Latham
Fullerton said most fans gave up trying to figure out signs but they “mustn’t do that. Someday right in the middle of a game, you’ll strike the key to the language and read through clear to the ninth inning.”
He compared that moment to getting “away one good drive,” in golf, “forever afterward you are a victim,” and can’t stop.
“Did you ever watch Hugh Jennings on the coaching line near first base during a hard-fought game? He doubles his fists, lifts one leg and shakes his foot, screams ‘E-yah’ in piercing tomes and stooping suddenly plucks at the grass, pecking at it like a hen. It looks foolish. I have heard spectators express wonder that a man of ability and nearing middle age could act so childishly. Yet hidden somewhere in the fantastic contortions and gestures of the Tigers’ leader there is a meaning, a code word, or signal that tells his warriors what he expects them to do.”
Jennings said of his signs:
“I change almost every day. I change every time I suspect there is a danger of the meanings being read. I am a believer in as few signals as possible and of giving them when they count, and I find that a lot of antics are effective in covering up the signals.”
Fullerton said Mack was “one of the most successful men” at “interpreting” opponents’ signs:
“Before the Chicago Cubs went into their disastrous series against the Athletics they were warned that if such a thing were possible Mack would have their signals. At the end of the game they called a meeting to revise signals, changing entirely, being certain the Athletics knew almost every kind of ball that was going to be pitched.”
Fullerton allowed that the Cubs instead might be tipping their pitches, because he was sitting with Ty Cobb during the series, and:
“(He) repeatedly called the turn on the ball that would be pitched before it was thrown, judging from the pitcher’s motion, and the Athletics may have been doing the same thing.”
Fullerton also said of the Cubs, that although they were “the cleverest baseball team in America, composed of smart men and a great manager, for years paid less attention to active coaching on the baselines,” than other teams.
“Possibly the reason was the confidence in their own judgment and their continued success, Frank Chance’s men made few blunders and the neglect was not noticeable, except to constant observers until 1908. Any player who happened to be idle went to the coaching lines and most of the time inexperienced substitutes did line duty. In 1908 during their fierce fight for the pennant, the realization of their carelessness was brought home to them and since then Chance has employed quick-thinking, clever men on the base lines, principally relying on (Ginger) Beaumont and (John) Kane.”

John Kane
Fullerton dated Chance’s new appreciation for competent coaching to July 17, 1908; that day the Cubs beat Christy Mathewson and the Giants 1 to 0 on an inside the park home run by Joe Tinker. Heinie Zimmerman was coaching third base for the Cubs.
The Chicago Inter Ocean described the play:
“Joe, the first man up in the fifth, hit one of Matty’s best as far as any ball could be hit in the grounds without going into the stands. Where the center field bleachers join the right field 25 cent seats is a V-shaped inclosure. Joe drove the ball away into this dent, and it took Cy Seymour some time to gather the elusive sphere. When Cy finally retrieved the ball, Tinker was rounding third.
“Zimmerman grasped this as the psychological moment to perpetrate one of the most blockheaded plays ever pulled off. He ran out onto the line and seized Joe, trying to hold him on third, when the ball was just starting to the diamond from deep center field. Joe struggled to get away, as his judgment told him he could get home, but Heinie held on with a grip of death. Finally, Tink wriggled away and started for the plate.”

Zimmerman
The paper said Tinker would have been thrown out had Al Bridwell’s throw to the plate been on target:
“Had Tinker been caught at the plate the 10,000 frenzied fans would have torn Zim limb from limb. Chance immediately sent Evers out to coach at third base and retired Zim to the dark confines of the Cubs’ bench.”
Thus, said Fullerton:
“Chance began to develop scientific coaching, and discovering its full value, took the lead in the matter, employing skilled coachers.”