638 POPULAR SCIENCE MONTHLY. 



between the hallucination and the stimulus which has generated 

 it. It is frequently very close, any change in the stimulus either 

 destroying the hallucination or making in it a corresponding 

 change. In the case of crystal gazing, for example, if one looks 

 at the image through a magnifying glass or prism, it is sometimes 

 destroyed and sometimes magnified or doubled. Very often 

 hallucinations originated independently appear to attach them- 

 selves in much the same way to some contiguous percept and be- 

 come practically a part of it. The element to which it is attached 

 is what the French investigators have termed the point de repere, 

 and M. Binet has endeavored to show that without such a point 

 de repere no hallucination can exist. The matter is still under 

 discussion, and must be set aside with this brief allusion. 



If we once admit that subconscious states exist, we are tempted 

 in many cases of hallucination to make use of the conception to 

 explain the facts. In the case of Mrs. Beasant's ghost, for ex- 

 ample, it may be that the memory was revived before the ap- 

 parition was seen, but remained subconscious until externalized 

 by some obscure agencies which one can not precisely specify. 

 An analogous experience — in this case a crystal vision — is given 

 by Miss X : * 



" I find in my notebook a memorandum of August 3d as to a 

 vision of a corner of a room, with a red carpet and walls decorated 

 in stripes of pink, white, and green, for which for many months I 

 was unable to account. Only a few days ago (May 10, 1889, is 

 the date of writing) I called on a friend whom I had not visited 

 since July, and whose house had, I observed, been newly and 

 handsomely decorated. A letter which she had written to me be- 

 fore leaving town in the summer waa by chance referred to, and 

 on returning home I sought it, to settle a disputed point, and found 

 that it was dated August 2d and contained the information that 

 her staircase had been painted and 'looked at present like a Nea- 

 politan ice.' This, I doubt not, supplied the coloring of my 

 l^icture." 



Here the development of the vision was influenced by an 

 allusion contained in a letter read the preceding day which was 

 no longer in mind. Now, one must suppose either that that 

 allusion still existed in some way and was capable of influencing 

 the vision, or that the vision had been suggested subconsciously, 

 had existed subconsciously, and had been brought to light by the 

 crystal, or that it had been suggested by the letter, forgotten, and 

 then revived. Of these three suppositions the last is the most 

 plausible, but it is difiicult in other cases to resort to it. Take 

 another case of Miss X 's : " On March 9th I saw in the crystal 



* Proceedings of the Society for Psychical Reieareb, vol. v, p. 512. 



