[Illustration: "A great wave of living protoplasm swept through the streets, licking them clean of life."] Worley leapt back, suddenly, as down the street from behind him there roared a long police-car, the fleeing mob ahead splitting to both sides as it thundered through. It skidded to a stop but yards from that advancing, glistening wave, and Worley saw blue-coated figures tumbling from it, staring in an amazement of horror at the great gleaming wave of protoplasm rolling toward them, then recovering themselves and lining swiftly across the street before it. Then there came the swift sharp drumming of powerful riot-guns, spraying tearing steel bullets into that advancing wave. At the same time came the dull detonation of grenades, hurled into the glistening masses, and for a moment Worley stared down toward them in sudden leaping hope. But the flood of protoplasm rolled onward, unchecked, unheeding. The bullets that tore through its jelly-like masses left holes that closed instantly of themselves. The bombs that exploded in those masses splashed them violently to every side, but in the next moment the glistening fragments had flowed smoothly forward of themselves; had joined together again in a solid flood; were sweeping resistlessly forward. Before the men lined across the street could comprehend the fact that the thing before them could not be killed, or even hurt, by human means, the wave had advanced upon them; a myriad tentacle-arms had whipped out of it toward them; and then it had gripped and had rolled over them, was gliding still smoothly on with their dark bodies visible in its clear gray masses. * * * * * Never afterward could Worley remember clearly the things that befell him in the next moments. He knew that with that sight a final mad frenzy of utter horror and despair had settled upon him, that with those other fleeing figures he was stumbling through the narrow streets toward the northward and the one chance of escape from the death-trap that the island had become, but his impressions of those mad moments were always hazy, dim. Striking, trampling, pushing, he and the panic-driven mobs about him fought their way through the choked streets, through the darkness of that dread night, while ever behind them, from south and east and west, there glided upon their track the mighty wave of protoplasm, calm, smooth, effortless, sweeping out over the island's tip and up through its narrow streets, absorbing into itself steadily the exhausted fugitives who fled before it, advancing northward and inward from the city's sides with its vast, glistening masses still steadily increased by the floods of protoplasm pouring up from the encircling waters.