Bruce had had a pleasantly lazy day with his friends in the first-line trenches. There had been much good food and more petting. And at last, comfortably tired of it all, he had gone to sleep. He had awakened in a most friendly mood, and a little hungry. Wherefore he had sallied forth in search of human companionship. He found plenty of soldiers who were more than willing to talk to him and make much of him. But, a little farther ahead, he saw his good friend, Sergeant Mahan, and others of his acquaintances, starting over the parapet on what promised to be a jolly evening stroll. All dogs find it hard to resist the mysterious lure of a walk in human companionship. True, the night was not an ideal one for a ramble, and the fog had a way of congealing wetly on Bruce's shaggy coat. Still, a damp coat was not enough of a discomfort to offset the joy of a stroll with his friends. So Bruce had followed the twelve men quietly into No Man's Land, falling decorously into step behind Mahan. It had not been much of a walk, for speed or for fun. For the humans went ridiculously slowly, and had an eccentric way of bunching together, every now and again, and then of stringing out into a shambling line. Still, it was a walk, and therefore better than loafing behind in the trenches. And Bruce had kept his noiseless place at the Sergeant's heels. Then--long before Mahan heard the approaching tramp of feet--Bruce caught not only the sound but the scent of the German platoon. The scent at once told him that the strangers were not of his own army. A German soldier and an American soldier--because of their difference in diet as well as for certain other and more cogent reasons--have by no means the same odor, to a collie's trained scent, nor to that of other breeds of war-dogs. Official records of dog-sentinels prove that. Aliens were nearing Bruce's friends. And the dog's ruff began to stand up. But Mahan and the rest seemed in no way concerned in spirit thereby--though, to the dog's understanding, they must surely be aware of the approach. So Bruce gave no further sign of displeasure. He was out for a walk, as a guest. He was not on sentry-duty. But when the nearest German was almost upon them, and all twelve Americans dropped to the ground, the collie became interested once more. A German stepped on the hand of one of his newest friends. And the friend yelled in pain. Whereat the German made as if to strike the stepped-on man. This was quite enough for loyal Bruce. Without so much as a growl of warning, he jumped at the offender. Dog and man tumbled earthward together. Then after an instant of flurry and noise, Bruce felt Mahan's fingers on his shoulder and heard the stark appeal of Mahan's whispered voice. Instantly the dog was a professional soldier once more--alertly obedient and resourceful.