By this time, a score of people were dancing up and down inside their door-yard fences, squalling "Mad dog!" and flinging at the black brute any missile they could lay hand to. A broken flower-pot cut the invalid's nose. A stone rebounded from his ribs. The raucous human yells completed the work the first dog had started. From a mere sufferer, the black mongrel had changed into a peril. The Mistress had motored over to the Hampton post-office, that afternoon, to mail some letters. Lad, as usual, had gone with her. She had left him in the car, while she went into the post-office. Lad lay there, in snug contentment, on the car's front seat; awaiting the return of his deity and keeping a watchful eye on anyone who chanced to loiter near the machine. Presently, he sat up. Leaning out, from one side of the seat, he stared down the hot roadway, in a direction whence a babel of highly exciting sounds began to issue. Apparently, beyond that kick-up of dust, a furlong below, all sorts of interesting things were happening. Lad's soft eyes took on a glint of eager curiosity; and he sniffed the still air for further clues as to the nature of the fun. A number of humans,--to judge by the racket,--were shouting and screaming; and the well-understood word, "dog," formed a large part of their clamor. Also, there were real dogs mixed up in the fracas; and more than one of them had blood on him. So much the collie's uncanny senses of smell and of hearing told him. Lad whimpered, far down in his throat. He had been left here to guard this car. It was his duty to stay where he was, until the Mistress should return. Yet, right behind him, there, a series of mighty entertaining things were happening,--things that he longed to investigate and to mix into. It was hard to do one's solemn duty as watchdog, when so much of wild interest was astir! Not once did it occur to Laddie to desert his post. But he could not forbear that low whimper and a glance of appeal toward the post-office. And now, out of the smear of flying dust, loomed a lurching black shape;--gigantic, terrible. It was coming straight toward the car; still almost in mid-road. Behind, less distinct, appeared running men. And a shot was fired. Somebody had run indoors for a pistol, before joining the chase. The same somebody, in the van of the pursuers, had opened fire; and was in danger of doing far more damage to life than could a dozen allegedly mad dogs. Just then, out from the post-office, came the Mistress. Crossing the narrow sidewalk, she neared the car. Lad stood up, wagging his plumed tail in welcome; his tiny white forepaws dancing a jig of eagerness on the leather seat-cushion. On reeled the black mongrel; crazed by noise and pain. His bleared eyes caught a flash of the Mistress's white dress, on the walk, fifteen feet in front of him and a yard or more to one side.