THAT full appreciation of the tremendous developments which have been wrought in the game may be realized, let us revert to the origin of football in this country, follow the various changes in the playing rules, and note their effect upon the tactics of the offense and defense.

Unlike the English game which for years has retained its most distinctive features, American football has shown constant advancement in new directions, so that at the present time it so abounds with innovations and new ideas as to be fundamentally different from that played in the various football epochs of the past.

By far the most interesting aspect of football is the struggle between the offense and defense. Superiority has lain first with one then with the other, the reasons for which we will now trace from the time when the game was divorced from the English Rugby. In the early seventies, when the game was played under English rules; there were fifteen players on a side. There was no successive possession of the ball, no downs, no signals, no interference for the runner, and no penalty for failure to make distance. After the number of players had been reduced to eleven, the first American legislation was to allow one team possession of the ball when an offensive play was to be attempted, in other words, an organized outlet of the scrimmage. In this lies the backbone around which the entire body of American football is attached.

Having allowed the offense possession of the ball a problem soon arose as to the proper method of preventing what was then called the "block game." As there were no rules relating to the number of downs, or distance to be gained, it became the practice of the offense to keep the ball continuously in their possession, irrespective of the distance gained or lost, so that even if a team was forced behind its own goal-line, the ball was taken out to the twenty-five yard line, at which point play was resumed without penalty.

Thus, in 1881 Yale and Princeton played a 0-0 tie, in which Princeton had possession of the ball during the entire first half, making a gain of only ten yards in forty minutes' play. Yale started the second half with the ball, and never once relinquished it until the game was finished.

To prevent the continuance of these tactics, rules were adopted in 1882, the first of which declared that if the offense were forced over their own goal-line, two points should accrue to the other team. More important was another rule which provided that the offense must, in three successive rushes, advance the ball five yards or retreat with it ten yards, failing to accomplish either, the ball to be surrendered to the defense. Not only did these rules prevent the monotonous tactics of the block game, but they were the cause of the present-day five yard lines which, striping the field of play, have earned for it the name "gridiron."

This five-yard rule so weakened the offense that the rule makers about the same time abolished the English rule which forbade an offensive player to block opponents while in advance of the ball. Thus the last vestige of Rugby was cast aside, and the corner-stone of our present system of interference was laid.

With this new agency at its command, the offense made great strides in strategy and tactics, and we find that through the adoption of signals, crude as they were, the defense soon crumbled before what were really the beginnings of an organized attack with the attendant importance of the quarterback to direct it.

In order to bolster up the defense, an innocent looking rule was passed in 1888, which legalized tackling the runner from the waist to the knees. As it turned out this low tackle introduced into the game a defensive weapon so powerful that the day of individual end running and dodging was doomed. In its stead the offensive rush-line was now contracted until the men stood shoulder to shoulder, and the halfbacks were moved up to within four or five yards of the scrimmage line to cope with the quick plunges into the line that the new game required.

Thus passed the beautiful open style of running which is so fondly remembered by the older generation of today; and in its place came the ugly, uncouth beginnings of mass play.

Ingenious inventions at once appeared along this line of tactical development. Yale utilized the new interference idea by sending a player through the line in advance of the runner, com-monplace now, but irresistible when first disclosed. Princeton, equally constructive, devised the play now familiarly known as "boxing the tackle." Simple now, but surprisingly formidable when first used against Yale in 1888. The defense soon met these innovations by placing a halfback, who before stood ten or fifteen yards from the scrimmage line, immediately behind each tackle, thus presenting a new invention called the "secondary defense," which was the beginning of the co-operative relationship between the defensive halfbacks and the line, which in turn accelerated the detailed development of position play and rush-line tactics.