An ordinary case of ecmnesia may present problems as insoluble in their way as those offered by spirit-possession itself. There may be in ecmnesia periods of life absolutely and permanently extruded from memory; and there may be also periods which are only temporarily thus extruded. Thus on Wednesday and Thursday I may be unaware of what I learnt and did on Monday and Tuesday; and then on Friday I may recover Monday's and Tuesday's knowledge, as well as retaining Wednesday's and Thursday's, so that my brain-cells have taken on, so to say, two separate lines of education since Sunday--that which began on Monday, and that which began on Wednesday. These intercurrent educations may have been naturally discordant, and may be fused in all kinds of ways in the ultimate synthesis. These processes are completely obscure; and all that can be said is that their mechanism probably belongs to the same unknown series of operations which ultimately lead to that completest break in the history of the brain-cells which consists in their intercalary occupation by an external spirit. Passing on to _genius_, which I discussed in my third chapter, it is noticeable that there also there is a certain degree of temporary substitution of one control for another over important brain-centres. We must here regard the subliminal self as an entity partially distinct from the supraliminal, and its occupation of these brain-centres habitually devoted to supraliminal work is a kind of possession, which illustrates in yet another way the rapid metastasis of psychical product (so to term it) of which these highest centres are capable. The highest genius would thus be the completest _self-possession_,--the occupation and dominance of the whole organism by those profoundest elements of the self which act from the fullest knowledge, and in the wisest way. The next main subject which fell under our description was _sleep_. And this state--the normal state which most resembles trance--has long ago suggested the question which first hints at the possibility of ecstasy, namely, What becomes of the soul during sleep? I think that our evidence has shown that sometimes during apparent ordinary sleep the spirit may travel away from the body, and may bring back a memory, more or less confused, of what it has seen in this clairvoyant excursion. This may indeed happen for brief flashes during waking moments also. But ordinary sleep seems to help the process; and deeper states of sleep--spontaneous or induced--seem still further to facilitate it. In the coma preceding death, or during that "suspended animation" which is sometimes taken for death, this travelling faculty has seemed to reach its highest point.