"Good," he said; "I will see you again," with a polite bow; and turning to the door which I had previously locked, he opened it softly, and with a quiet "Good night" disappeared in the hall-way. I looked after him with bewildered senses; but a sudden impulse caused me to glance toward the table, when I saw that he had forgotten his knife. With the view of returning this, I reached to pick it up, but my finger tips no sooner touched the handle than a sudden chill shivered along my nerves. Not as an electric shock, but rather as a sensation of extreme cold was the current that ran through me in an instant. Rushing into the hall-way to the landing of the stairs, I called after the mysterious being, "You have forgotten your knife," but beyond the faint echo of my voice, I heard no sound. The phantom was gone. A moment later I was at the foot of the stairs, and had thrown open the door. A street lamp shed an uncertain light in front of the house. I stepped out and listened intently for a moment, but not a sound was audible, if indeed I except the beating of my own heart, which throbbed so wildly that I fancied I heard it. No footfall echoed from the deserted streets; all was silent as a churchyard, and I closed and locked the door softly, tiptoed my way back to my room, and sank collapsed into an easy chair. I was more than exhausted; I quivered from head to foot, not with cold, but with a strange nervous chill that found intensest expression in my spinal column, and seemed to flash up and down my back vibrating like a feverous pulse. This active pain was succeeded by a feeling of frozen numbness, and I sat I know not how long, trying to tranquilize myself and think temperately of the night's occurrence. By degrees I recovered my normal sensations, and directing my will in the channel of sober reasoning, I said to myself: "There can be no mistake about his visit, for his knife is here as a witness to the fact. So much is sure, and I will secure that testimony at all events." With this reflection I turned to the table, but to my astonishment I discovered that the knife had disappeared. It needed but this miracle to start the perspiration in great cold beads from every pore. My brain was in a whirl, and reeling into a chair, I covered my face with my hands. How long I sat in this posture I do not remember. I only know that I began to doubt my own sanity, and wondered if this were not the way people became deranged. Had not my peculiar habits of isolation, irregular and intense study, erratic living, all conspired to unseat reason? Surely here was every ground to believe so; and yet I was able still to think consistently and hold steadily to a single line of thought. Insane people can not do that, I reflected, and gradually the tremor and excitement wore away. When I had become calmer and more collected, and my sober judgment said, "Go to bed; sleep just as long as you can; hold your eyelids down, and