At that time it was my impression that in these séances Lombroso’s interest was in the spiritualists, not in the “spirits,” and, in the next place, in the abnormal trance-state of the mediums. This was undoubtedly so at that time; but his subsequent publications have shown that at a later date he went much further than this, and ascribed to the brain-substance the faculty of exercising a powerful influence beyond the periphery of the body (although, according to the dominant and still unshaken opinion, the function of the brain-substance is subject to the law of isolated nervous conduction). For example, in the _Annales des Sciences Psychiques_, 1892, p. 146 _et seq._, Lombroso wrote as follows: “Not one of these facts (which we must admit to be facts, since we cannot deny that which we have seen with our own eyes) is of a nature to render it necessary to suppose for its explanation the existence of a world different from that admitted by neuropathologists to exist. I see nothing inadmissible in the supposition that in hysterical and hypnotized persons the stimulation of certain centres, which become powerful owing to the paralyzing of all the others, and thus give rise to a transposition and transmission of psychical forces, may also result in a transformation into luminous or motor force. In this way we can understand how the force, which I will call cortical or cerebral, of a medium can, for example, raise a table from the floor, pluck someone by the beard, strike him or caress him—very frequent phenomena in these séances. In certain conditions, which are very rare, the cerebral movement which we call thought is transmitted to distance, sometimes small, sometimes very considerable. Now, in the same way in which this force is transmitted, it may also become transformed, and the psychic force may manifest itself as a motor force. Do we not see the magnet give rise to a deflection of the compass-needle without any visible intermediary?” We must not without further consideration dismiss this idea as absurd, because a very simple experiment suffices to show that the well-known and continuous heat-radiation from the living body—that is to say, the dispersal from the body of ultra-red etheric undulations—undergoes notable and easily measurable changes, in association with every change in the intellectual or emotional equilibrium, just as the arterial pulse, which changes under the influence of emotional disturbance, gives rise to varying oscillations in the air. But we do not possess sense-organs adequate to detect either these atmospheric or these etheric undulations. We were unable to establish their existence until physiology had given us Mosso’s plethysmograph and Zamboni’s dry battery.