As he shouted, he drew a tiny pellet from his inner pocket and hurled it point-blank through the vaporous body of the specter.

Even as I seized Spence’s hand and fought with him for possession of the pistol, I saw the transformation from the tail of my eye. As de Grandin’s missile tore through its unsubstantial substance, the vision-woman seemed to shrink in upon herself, to become suddenly more compact, thinner, scrawny. Her rounded bosom flattened to mere folds of leatherlike skin stretched drum-tight above staring ribs, her slender graceful hands were horrid, claw-tipped talons, and the yearning, enticing face of Dorothy Spence became a mask of hideous, implacable hate, great-eyed, thin-lipped, beak-nosed—such a face as the demons of hell might show after a million years of burning in the infernal fires. A screech like the keening of all the owls in the world together split the fog-wrapped stillness of the night, and the monstrous thing before us seemed suddenly to shrivel, shrink to a mere spot of baleful, phosphorescent fire, and disappear like a snuffed-out candle’s flame.

Spence saw it, too. The pistol dropped from his nerveless fingers to the car’s floor with a soft thud, and his arm went limp in my grasp as he fell forward in a dead faint.

“Parbleu,” de Grandin swore softly as he climbed into the unconscious lad’s car. “Let us drive forward, Friend Trowbridge. We will take him home and administer a soporific. He must sleep, this poor one, or the memory of what we have shown him will rob him of his reason.”

So, we carried Alvin Spence to his home, administered a hypnotic and left him in the care of his wondering mother with instructions to repeat the dose if he should wake.

It was a mile or more to the nearest bus station, and we set out at a brisk walk, our heels hitting sharply against the frosty concrete of the road.

“What in the world was it, de Grandin?” I asked as we marched in step down the darkened highway. “It was the most horrible—”

“Parbleu,” he interrupted, “someone comes this way in a monstrous hurry!”

His remark was no exaggeration. Driven as though pursued by all the furies from pandemonium, came a light motorcar with plain black sides and a curving top. “Look out!” the driver warned as he recognized me and came to a bumping halt. “Look out, Dr. Trowbridge, it’s walking! It got out and walked!”

De Grandin regarded him with an expression of comic bewilderment. “Now what is it that walks, mon brave?” he demanded. “Mordieu, you chatter like a monkey with a handful of hot chestnuts! What is it that walks, and why must we look out for it, hein?”