Mr.Galton, out of all his packets of reports of hallucinations, does not even allude to a veracious example, whether he has records of such a thing or not.
Such reports, however, are ghost stories, "which we now proceed," or continue, "to narrate".

The reader will do well to remember that while everything ghostly, and not to be explained by known physical facts, is in the view of science a hallucination, every hallucination is not a ghost for the purposes of story-telling.

The hallucination must, for story-telling purposes, be _veracious_.
Following our usual method, we naturally begin with the anecdotes least trying to the judicial faculties, and most capable of an ordinary explanation.

Perhaps of all the senses, the sense of touch, though in some ways the surest, is in others the most easily deceived.
Some people who cannot call up a clear mental image of things seen, say a saltcellar, can readily call up a mental revival of the feeling of touching salt.

Again, a slight accidental throb, or leap of a sinew or vein, may feel so like a touch that we turn round to see who touched us.