"At last, as I came once again in view of the Thames, with the moon reflected in the water, and the dark arches of the bridge looking black and solemn contrasted against the silvery stream, I saw before me, a long way before me, a man whose figure stood out in relief against the white road--a man walking wearily and with evident difficulty--a man, too, slightly deformed. "I walked on rapidly, till within about a score yards of him, then I slackened my speed, and taking care that my leisurely footsteps should be heard, overtook him by degrees, and then, when I was quite abreast, asked if he could oblige me with a light. "He looked up in my face, and said, with a forced, painful smile and studied courtesy of manner: "'I am sorry, sir, to say that I do not smoke.' "I do not know exactly what reply I made. I know his countenance struck me so forcibly, it was with difficulty I could utter some commonplace remark concerning the beauty of the night. "'I do not like moonlight,' he said, and as he said it, something, a connection of ideas, or a momentary speculation, came upon me so suddenly, that once again I failed to reply coherently, but asked if he could tell me the shortest way to the Brompton Road. "'To which end?' he inquired. "'That nearest Hyde Park Corner,' I answered. "As it turned out, no question could have served my purpose better. "'I am going part of the way there,' he said, 'and will show you the nearest route--that is,' he added, 'if you can accommodate your pace to mine,' and he pointed, as he spoke, to his right foot, which evidently was causing him considerable pain. "Now, that was something quite in my way, and by degrees I got him to tell me about the accident which had caused his slight deformity. I told him I was a doctor, and had been to see a patient, and so led him on to talk about sickness and disease, till at length he touched upon diseases of a morbid character; asking me if it were true that in some special maladies the patient was haunted by an apparition which appeared at a particular hour. "I told him it was quite true, and that such cases were peculiarly distressing, and generally proved most difficult to cure--mentioning several well-authenticated instances, which I do not mean to detail to you, Patterson, as I know you have an aversion to anything savouring of medical shop. "'You doctors do not believe in the actual existence of any such apparitions, of course?' he remarked, after a pause. "I told him we did not; that we knew they had their rise and origin solely in the malady of the patient. "'And yet,' he said, 'some ghost stories--I am not now speaking of those associated with disease, are very extraordinary, unaccountable--'