If the play called for does not indicate which back is to carry the ball, the quarter-back should have a silent visible signal of some kind. Usually the quarter uses finger signals, putting the hand behind his leg where it cannot be seen by the opponents. One finger may indicate the left half; two fingers, the right half; and three fingers, the full-back, or middle man. Pulling up trousers or stockings, or scratching the head, may also indicate what man is to take the ball. The signal should be called once only. The second calling is not necessary at all; besides, it slows up the game. Men feel that they have plenty of time after the first call, and loaf to their places. They are not particular about catching the first signal, since it must be given again. The signal should be called by the quarter-back, as the play must be started by him, and he is in a better position to see the best opportunity for the next play, and he can be easily heard from either flank of the line. If the captain should change a play, he should not call the signal himself, but tell his quarter the play he wants. The signal should be called loudly enough to be heard by every man in the midst of the din of battle. The quarter should put as much earnestness and enthusiasm as possible in the calling of the signals. Snap them out, and let the merry war go on! Where sequences are played without vocal signal, the quarter should have some sign for his back, although it is not absolutely necessary. Sequences should be short. The time to play them is at the opening of the game. They cannot be played continuously, as the contingencies of the game cannot easily be foreseen. _Generalship._--The generalship of the game devolves upon the captain. There must be one head on the field, and only one. A game may be largely planned before going upon the field. At the time the game is being mapped out is the occasion for consultation with coaches and players. Before the game it may be decided what is to be done under given conditions of wind and weather, or what is to be done if the team gets the ball at start-off or not. By studying an opponent's preceding games, it is sometimes possible to determine somewhat in advance the kind of game that is likely to succeed against that particular team. The strength and weakness of the team must be considered also.