Atta Boy's Last Race (1916)

Lois Brandon ( Dorothy Gish ) is in love with racehorse owner Jim Spencer, but she refuses to marry him. Since her father committed suicide because of racing debts, Lois now hates the racetrack atmosphere. Jim vows to leave the business after winning one more race, and he sells his horses to Jarvis Johnson, betting the money on Atta Boy, who breaks down in the stretch. Lois claims Atta Boy and nurses him back to health, then enters him in a race without knowing that it has been "fixed" by Johnson. At the last minute, Lois finds out about the fix and yells to Jim to switch his bets to Johnson's horse. Atta Boy manages to win, but Jim had not heard Lois' warning to change his bet, and so he wins enough to leave the track forever.