4. An on-side kick must go at least 20 yards into the opponent's territory before it can be recovered by the kicking side.

Briefly as these changes are outlined, it is probable that they will affect the playing of the game in many ways, some perhaps unforeseen. Some of their effects however, may be conjectured, and a further exposition and analysis of the rules in the order in which they appear in the Official Rule Book is added.

I. The first change noted is in the diagram of the field. The longitudinal lines are now omitted, because, as the first man who receives the ball from the snapper-back may cross the line of scrimmage at any point and as the forward pass may be thrown over the line at any point, these longitudinal marks are no longer necessary. The field will once more resemble a "gridiron."

II. The next rule affected is that regarding the substitution of players. The new rule states that a player who has been removed for any cause, except for disqualification or suspension, may be once returned to the game at the beginning of any subsequent period. This rule was adopted to prevent any excuse for allowing a player who is thoroughly exhausted to remain in the game. Heretofore, it has been the practice of coaches, especially among the smaller colleges and school teams, to allow their players to remain in the game, even though such players were oftentimes seriously injured or thoroughly worn out, with the excuse that they had no available substitute for that position and that the injured player might recover between the halves. The foregoing rule should tend to lessen injuries, and will also compel coaches to have the proper number of substitutes for each of their players.

III. The game is now divided into four periods of 15 minutes each. There is to be the usual intermission between the second and third periods, but only 3 minutes intermission between the first and second and the third and fourth periods. During this short intermission, no player of either side is allowed to leave the field of play and no representative, except one from either side in order to look after the physical condition of the players, may come upon the field of play. At the beginning of the second and fourth periods, the teams change goals, but the possession of the ball, the down, the relative spot of the down, and the distance to be gained, all remain the same as at the termination of the previous period. The teams do not change goals after a try-at-goal following a touchdown or after a goal from the field, but the side scored upon then has the option of kicking off or of having their opponents kick off. At the beginning of the third period, the teams change goals, but the side which kicked off at the beginning of the first period now has the option of kicking off to their opponents from the middle of the field, or of receiving the kick-off as heretofore. The result of this subdivision of the halves will certainly make the game less taxing upon the players and the change of goals after each period should nearly equalize the advantage or disadvantage of wind and sun, slope of field, etc.

IV. "Crawling" has been defined as an attempt to advance the ball by the runner after the ball has been declared dead and any infringement of this rule will be penalized. The effect of this rule will be two-fold: 1st. It will prevent a man from attempting to gain his distance after he is fairly "down." 2d. It will allow no excuse for "piling up" by players of the defensive side. In previous years the runner who squirmed along the ground after the ball was declared dead lost only the distance he had gained by so squirming or crawling, and officials were often lax in imposing this small penalty. Consequently it was a great temptation for the players of the defense to pounce upon a player who was fairly tackled and thrown in order to prevent his gaining further distance.

V. Seven players of the side holding the ball must now be on the line of scrimmage when the ball is put in play. This is one more man than was required last year. The ends cannot now run with the ball or act as interferers as readily as when they were allowed to stand behind the line of scrimmage. This rule was passed in order to lessen the weight of the attack on the defensive line.

VI. The player who first receives the ball when it is snapped back may carry it across the line of scrimmage at any point. Last year, this player was compelled to cross the line of scrimmage at a point at least five yards from where the ball was put in play. Now the rule does away with this restriction and allows a quicker and more versatile form of attack. It will also tend to prevent the defense from "spreading out" in order to defend their territory better against forward passes and on-side kicks.

VII. The rules relating to a forward pass and on-side kick are considerably changed. Their application to the general scheme of play, however, is comparatively simple. A forward pass may cross the line of scrimmage at any point, but no player may make such a forward pass unless he is at least five yards back of the line of scrimmage. Of the side making the pass, only the backs and the two men on the ends of the line of scrimmage may receive it, and they must catch it before it has gone 20 yards beyond the line of scrimmage.

The rule that the pass might cross the line of scrimmage at any point was adopted to simplify the conditions attending the pass, and encourage plays of this nature. The limitation of the length of the pass to 20 yards was established to prevent long forward passes at the expense of kicking, especially as the penalty for an "incomplete" forward pass is lessened; and, except on the line of scrimmage and by the recovery of the ball by an opponent, the receiver of the pass is unhindered in his path to the ball.

An on-side kick, when touching the ground, does not put "on-side" the players of the kicking sides (i.e., so that they may recover the ball) until it has gone at least 20 yards beyond the line of scrimmage. An on-side kick of less than 20 yards was found often to result in dangerous collisions and a general scramble for the ball, and it was therefore thought advisable to compel a more scientific attempt at this play by legalizing the play only after the ball had struck the ground and advanced 20 yards beyond the scrimmage line.

Rules relating to both on-side kick and forward pass. There are also rules to govern the actions of players when a forward pass or on-side kick is made. Formerly, the most effective way to prevent the recovery of the ball on such a play was to check or block off the players on the offense while they were endeavoring to recover the ball. As a consequence men unprepared for a shock or off their balance while reaching for the ball were heavily thrown. Now, however, on a kick or forward pass, from the time a player on the offense crosses the line of scrimmage into his opponent's