Philosophers occasionally regret the limited number of their senses, and think a world of knowledge would flow from their possessing but one more. Now, persons of highly-wrought nervous systems have what is equivalent to a new sense, in their augmentation of natural sensibility. But philosophers will not accept this equivalent. They must have the boon from nature their own way, or not at all.
To turn elsewhere.--We may now look into a broader seam of illusive power--one which lies entirely within ourselves, and needs no objective influence to bring its ghost-producing fertility into play. Let me exemplify it in operation.
A young gentleman, who has recently left Oxford, told me, that he was one evening at a supper-party in college, when they were joined by a common friend on his return from hunting. They expected him, but were struck with his appearance. He was pale and agitated. On questioning him, they learned the cause. During the latter part of his ride home, he had been accompanied by a horseman, who kept exact pace with him, the rider and horse being facsimiles of himself and the steed he rode, even to the copy of a newfangled bit he sported that day for the first time. The apparition vanished on his entering the town. He had, in fact, seen his double or fetch, and it had shaken his nerves pretty considerably. His friends advised him to consult the college tutor, who failed not to give him some good advice, and hoped the warning would not be thrown away. My informant, who thought the whole matter very serious, and was disposed to believe the unearthly visit to have been no idle one, added, that it _had_ made the ghost-seer, for the time at all events, a wiser and better man.
In more ignorant times, the appearance of one's fetch was held to be of very alarming import, and to menace either death or serious personal harm. Now, it is known to be one of the commonest forms in which _sensorial illusions_ shape themselves. And these are matters of every-day occurrence.
It would seem, that when the blood is heated or the nervous system over-strained, we are liable to attach reality to the mere productions of the imagination. There must be few who have not had personal experience of this affection. In the first night of a febrile attack, and often in the progress of fever, the bed-hangings appear to the patient swarming with human faces, generally of a disagreeable and menacing expression. With some, opium will produce a host of similar visitants. In much illness, I have often myself taken this drug, and always hoped it would provide me a crop of apparitions that I might analyse. But I was disappointed; opium I found to give me only a great tranquillity and clearness of thought. Once or twice only have I had a vision, and that but a transitory landscape. I used in vain to look upon that _black mixture_ which lies before one in the dark, and try to make its fragmentary lights arrange themselves into definite shapes. And I have imaged to my mind familiar scenes or faces, (as in the daytime a strong conception will half realise such,) but they were not more distinct then than formerly,--ideas only and perfectly transient. But, as I have said, once or twice I have had the satisfaction of seeing a bright and coloured landscape spread before my view; yet unlike reality, and more resembling a diorama, occupying a rectangle on the black mixture before my eyes. It was not a known and familiar scene, but a brilliant sketch, made out of materials I remembered, but could not by a deliberate effort _have combined_ so effectively. It was a spontaneous throe of the imagination, which had force to overpersuade the organs of perception.