A possible explanation of a different kind has been already illustrated by the story quoted on page 153, where it was shown that a solitary hallucination had grown in the course of five-and-twenty years into a collective vision. The narrator in this case was a child at the time of the alleged experience. Children and uneducated persons generally, who are not prone to analyse their own sensations, seem liable after a certain interval to mistake the image called up by another's recital for an actual experience of their own; and this is especially likely to occur when the auditor was present at the time of the experience or familiar with the scene of the occurrence. Indeed, most persons who visualise with moderate facility are probably liable to this form of mistake on a small scale. I had about five years since an example of this in my own case. A friend had described to me minutely some simple apparatus of his own invention. About a year later he brought the apparatus to London and offered to show it to me. I replied that I had already seen it; but on being confronted with it I found the proportions and general appearance of the actual object quite unlike my mental image of it. I had in fact never seen the object, but the image which I had mentally constructed to enable me to follow my friend's description a year before remained so vivid as to lead me to believe that it was founded on actual sensation. But a sensory hallucination is too striking and unusual an experience to be readily feigned, and it is very improbable that the memory of educated persons, at any rate, would be untrustworthy as regards their recent experiences of the kind. As already explained, the accounts of this and other forms of telepathic affection included in this book have in almost all cases been written down within ten years of the event.