The way to induce trance-umbra, is to administer a little dose of mesmerism. One operator, like Dr. Darling, (I quote from Dr. Gregory’s most instructive and interesting _Letters on Animal Magnetism_,) directs his patient to sit still with his eyes fixed, and his attention concentrated on a coin held in his hand, or on a double-convex bit of zinc with a central portion of copper so held. This is, in truth, a gentle dose of hypnotism. The patient looks in quiet repose at a small object held in his hand or his lap, instead of fatiguing his sensations by straining the eye-balls upwards. Suppose a group of a dozen persons sitting thus in a half-darkened, still room, preserving a studied quietude, and concentrating their attention on one point of easy vision; in from fifteen to twenty minutes one or more is found to be in the state of trance-umbra. Mr. Lewis (I quote again the same authority) employs a different process. He eyes his patients intently as they sit in a row before him, still and composed, with a concentrated will, and its full outward expression by him, to influence their psychical condition. In five minutes it often happens that the state of trance-umbra supervenes.
In the mean time, what has marked its arrival? The Rev. R. S. F. writes me, that he had been three times the subject of the first of the two methods: the operator was Mr. Stone, Lecturer at the Marylebone Scientific Institution. The first two experiments were successful, the third failed. Then Mr. F. writes, “The only circumstance which I noticed (bearing upon the above question) in myself, and which I afterwards found tallied with the experience of others, was this: On the two occasions when I was affected, after about ten minutes the coin began to disappear from my sight, and to reappear a confused, brilliant substance, similar to those appearances which remain on the retina after one has been looking towards the sun for a few minutes, and I seemed for the moment to have fallen into a half-dreamy state; but in the subsequent part of the experiments, I appeared to myself to be in my ordinary state. On the third occasion, when the experiment failed with myself and with all the others, (which I think might be accounted for by the accidental irregularity of the proceedings,) I did not experience the sensations mentioned above.” This account tallies with other evidence upon the point; a brief period of disturbed sensation, or threatening confusion, or loss of consciousness, passes over the patient. The wing of the unseen power, to speak figuratively, has cast its shadow upon him. It is evident that this transient psychical disturbance is the same phenomenon with that which Zschokke experienced whenever his seer-gift was manifested. The agency which thus can at pleasure be used to call forth trance-umbra, is the same which employed longer, or more intensely, produces perfect trance. The little dose thrilling through the system, without driving sense and apprehension from their usual seats, seems, as it were, to remove their fastenings; to throw up, as it were, the sashes of the body, so that the soul can now look forth and see, not as through a glass, darkly, but free to grasp directly things out of its corporeal tenement, whether of the nature of matter or mind.