"I guess that will hold them for a while," crowed Billy, as they rested for a few minutes after their return. "We certainly slashed them good and plenty," exulted Frank, as he washed up a scratched shoulder that had been struck by a splinter of shrapnel. "If the rest of the line is holding as well as our fellows, the drive will be ended almost as soon as it began," remarked Bart. "And Heinie was going to walk all over us, was he?" grinned Billy. "He's got another guess coming." But their amazement was great a few minutes later when the order came for the regiment to fall back. "Fall back!" howled Billy when he heard the order. "What is this, a joke?" "Why should we fall back, when we've just licked the tar out of the Heinies?" growled Bart. "Orders are orders," said Frank briefly. "I suppose our commanders know what they're doing. But it certainly is tough luck." Their officers no doubt felt an equal chagrin, but the need was imperative. The Germans had struck along a front of fifty miles. At many points they had encountered a resistance as fierce and determined as that put up by the old Thirty-seventh and its companion regiments of the same division. But at others they had been more successful. They had introduced a new kind of tactics that had never been used before on the western front, although it had been employed successfully in Russia. These were the so-called Von Hutier tactics whereby, when a division was used up, instead of falling back it simply opened up and let a fresh division pass through and take up the burden. The old plan had been to clear up everything as one went along. The idea of the new tactics was to press swiftly ahead even if they left behind them machine-gun nests and strong enemy positions. These could be cleaned up later one by one, while in front the swift advance was intended to demoralize the opposing army and throw it out of formation by the very speed of the progress. The plan, like every other, had its weak points. It involved a very heavy loss of men because of the masses in which they moved forward, and it also exposed its flank by penetrating too rapidly into the host lines before the artillery could be brought up for support. But if successful, it was almost sure to break the enemy's line and throw it into confusion. Later on the Allies were to learn how they might most easily frustrate these tactics. But at the start of the great drive the plan met with considerable success because of its novelty.