"In some instances it may be difficult to decide whether spectral appearances and spectral noises proceed from physical derangement or from an overwrought state of mind. Want of exercise and amusement may also be a prevailing cause. A friend mentions to us the following case: An acquaintance of his, a merchant, in London, who had for years paid very close attention to business, was one day, while alone in his counting house, very much surprised to hear, as he imagined, persons outside the door talking freely about him. Thinking it was some acquaintances who were playing off a trick, he opened the door to request them to come in, when to his amazement, he found that nobody was there. He again sat down to his desk, and in a few minutes the same dialogue recommenced. The language was very alarming. One voice seemed to say: 'We have the scoundrel in his own counting house; let us go in and seize him.' 'Certainly,' replied the other voice, 'it is right to take him; he has been guilty of a great crime, and ought to be brought to condign punishment.' Alarmed at these threats, the bewildered merchant rushed to the door; and there again no person was to be seen. He now locked his door and went home; but the voices, as he thought, followed him through the crowd, and he arrived at his house in a most unenviable state of mind. Inclined to ascribe the voices to derangement in mind, he sent for a medical attendant, and told his case, and a certain kind of treatment was prescribed. This, however, failed; the voices menacing him with punishment for purely imaginary crimes continued, and he was reduced to the brink of despair. At length a friend prescribed entire relaxation from business, and a daily game of cricket, which, to his great relief, proved an effectual remedy. The exercise banished the phantom voices, and they were no more heard." "So you think that I am in need of out-door exercise?" "Exactly." "And that my experience was illusory, the result of vertigo, or some temporary calenture of the brain?" "To be plain with you, yes." "But I asked you a while ago if specters or phantoms ever leave tangible evidence of their presence." The Professor's eyes dilated in interrogation. I continued: "Well, this one did. After I had followed him out, I found on the table a long, white hair, which I still have," and producing the little coil from my pocket-book, I handed it to him. He examined it curiously, eyed me furtively, and handed it back with the cautious remark: "I think you had better commence your exercise at once." CHAPTER III. A SECOND INTERVIEW WITH THE MYSTERIOUS VISITOR.