Phrased in this manner, the telepathic impact seemed the less startling, the less extreme hypothesis of the two,--mainly, perhaps, because the picture which it called up was left so vague and obscure. But now instead of a fleeting hallucination we have to deal with a strong and lasting impulse--such, for instance, as the girl's impulse to _write_, in Dr. Liébeault's case (Appendix VIII. C):--an impulse which seems to come from the depths of the being, and which (like a post-hypnotic suggestion) may override even strong disinclination, and keep the automatist uncomfortable until it has worked itself out. We may still call this a _telepathic impact_, if we will, but we shall find it hard to distinguish that term from a _psychical invasion_. This strong, yet apparently alien, motor innervation corresponds in fact as closely as possible to our idea of an _invasion_--an invasion no longer of the room only in which the percipient is sitting, but of his own body and his own powers. It is an invasion which, if sufficiently prolonged, would become a _possession_; and it both unites and intensifies those two earlier conjectures;--of telepathic impact on the percipient's mind, and of "phantasmogenetic presence" in the percipient's surroundings. What seemed at first a mere impact is tending to become a persistent control; what seemed an incursion merely into the percipient's environment has become an incursion into his organism itself. As has been usual in this inquiry, this slight forward step from vagueness to comparative clearness of conception introduces us at once to a whole series of novel problems. Yet, as we have also learnt to expect, some of our earlier phenomena may have to be called in with advantage to illustrate phenomena more advanced. In cases of split personality, to begin with, we have seen just the same phenomena occurring where certainly no personality was concerned save the percipient's own. We have seen a section of the subliminal self partially or temporarily dominating the organism; perhaps controlling permanently one arm alone;[193] or perhaps controlling intermittently the whole nervous system;--and all this with varying degrees of displacement of the primary personality. Similarly with post-hypnotic suggestion. We have seen the subliminal self ordered to write (say) "It has left off raining"--and thereupon writing the words without the conscious will of the automatist--and again with varying degrees of displacement of the waking self. The step hence to such a case as Mrs. Newnham's is thus not a very long one. Mrs. Newnham's subliminal self, exercising supernormal faculty, and by some effort of its own, acquires certain facts from Mr. Newnham's mind, and uses her hand to write them down automatically. The great problem here introduced is how the subliminal self acquires the facts, rather than how it succeeds in writing them down when it has once acquired them.