has the feeling, more or less precise, that a phenomenon is about to take place. Eusapia Paladino often announces what is coming. In this case the nervous energy, employed to realise the phenomenon, would be in connection with the conscious nervous centres of the medium only; and she would appear to the sitters to be subjected to an extraneous personal will. Eusapia attributes it to ‘John,’ who seems to have the characteristics of a secondary personality. Such appears to me to be the genesis of the personification, in the greater number of cases observed by me. There are others, however, where this explication is less satisfactory. I do not hide from myself how difficult it is to admit the hypothesis I have just formulated. We are ill-prepared to consider the _psychic force_ as identical, at least in its essence, with that which circulates in our nerves; and we are no better prepared to believe, that this force may be able to serve as a vehicle to a part of our personal or subliminal consciousness, or to think that it can preserve any connection with our psychic centres, when it acts beyond the limits of the body. Nevertheless, it looks as though it were really so, in the greater number of cases. These data suffice to render comprehensible the possible mechanism of raps and movements without contact. It is not even necessary to suppose that the nervous force acts beyond the limits of the body, if we admit that the experimenters create around them a sort of magnetic field. The nervous force would reach a maximum of potentiality in the experimenters or in the medium; the objects placed within the field would have a different potentiality; according to the conditions, we would have phenomena of attraction or repulsion. In this way we could understand motor phenomena. Raps are less easily explained, unless we consider them as facts analogous to electrical discharges. The rap would then be equivalent to the noise of a spark; it would be invisible, though in some cases it might be perceived. Lights and forms raise problems much more difficult of solution. They may be susceptible of the following explanation: we will suppose that particles of a very attenuated substance, _e.g._ the ether or any other kind of rarefied matter, existed capable of being acted upon by nerve force; they would become charged, and dispersed, according to the lines of force, and these lines would be determined by the action of nerve centres, and would take form corresponding to those particular centres. They would have a certain plasticity, if I may thus express myself, and this plasticity would be in connection with those centres, possessing preponderating physiological activity. If this connection existed with the superior ideative centres, we would have intelligible, definite forms, such as faces of human beings, heads of animals, and objects; should connection with the inferior centres be established, undefined forms only would be obtained.