He dared not do that. He thought then of going to the front of the house, and watching there, and endeavoring to intercept James and Clemency before they turned into the driveway. But he felt that he could not for one second relax his watch upon the watching man, and he had no guarantee whatever that, at the first sound of wheels, the man himself would not make for the front of the house. Then he thought, as always, of not disturbing the sick woman whose room faced the road. It seemed to him that his only course was to remain where he was and wait for the return of Aaron before James and Clemency. He knew now that the horse must have balked. His only hope was that James and Clemency, since it was such a fine night, and time is so short for lovers, might take such a long drive that even the balky mare might relent. Always he heard at intervals the trot of a horse, which only existed in his imagination. He began to wonder if he should know when Aaron, or Clemency and James, actually did drive into the yard, if he should be quick enough. Suddenly he thought of the dog: that he would follow him, and of what might happen. The dog's chain-leash was on the table. He stole across, got it, fastened it to the animal's collar, and made the end secure to a staple which he had had fixed in the wall for that purpose. As yet no intention of injury to the man except in self-defense was in his mind. If actually attacked, he must defend himself, of course, but he wished more than anything to drive the intruder away with no collision. That was what he hoped for. The time went on, and the strain upon the doctor's nerves was nearly driving him mad. Sometimes the mare balked for hours. He began to hope that Aaron would leave her, and return home on foot. That would settle the matter. But he remembered a strange trait of obstinacy in Aaron. He remembered how he had once actually sat all night in the buggy while the mare balked. The man balked as well as the horse. "The damned fool," he muttered to himself in an agony. The dog growled in response. Then it was that first the thought came to Gordon of what might be done to save them all. He stood aghast with the horror of it. He was essentially a man of peace himself, unless driven to the wall. He was a good fighter at bay, but there was in his heart, along with strength, utter good-will and gentleness toward all his kind. He only wished to go his way in peace, and for those whom he loved to go in peace, but that had been denied him. He began considering the nature of the man whose dark figure remained motionless on the driveway. He knew him from the first. It sounded sensational, his recapitulation of his knowledge, but it was entirely true. It was that awful truth, which is past human belief, which no man dares put into fiction. That man out there had been from his birth a distinct power for evil upon the face of the earth. He had menaced all creation, so far as one personality may menace it. He was a