(_e_) I have already said a few words about the sudden sensation of fatigue, which is felt when an important phenomenon occurs. I have carefully examined the state of the assistants before and after the seances, and I have invariably noticed that most of the experimenters were tired after a successful seance. This fatigue appears to be in fairly exact proportion to the results obtained. I speak of parakinetic and telekinetic results; for it must be noted that the fatigue determined by these abnormal movements is not identical—at least in the case of the medium—with the fatigue which other phenomena appear to occasion. Movements without contact entail a lassitude, comparable to that ensuing after a long walk or prolonged physical exercise. III. The last observation leads me to the examination of my third proposition. This is, that the force employed in the production of para or telekinetic phenomena has, probably, a connection with the organism of the experimenters. The analysis I have just made allows one to surmise the very serious reasons, which lead me to formulate this conclusion so precisely. The first of these reasons is the correlation, existing between the movements and muscular contractions of the sitters and the paranormal movements. I have pointed out that this connection appears, in reality, to reside in the muscular contraction rather than in the free movements of the limbs: this is a first ascertainment. There is yet another, that provoked paranormal phenomena are, apparently, approximatively proportional to the movement executed by the experimenter and the effort he makes. These two first points appear to me to be acquired, and the correlation observed between the muscular effort and the paranormal movement, indicates reciprocal dependence between these two phenomena. We may go further, and try to discover whether the relation indicated resides in the fact, itself, of muscular contraction, or in the physiological fact which provokes it—that is to say, the nervous discharge. Observation tends to show, that it is with the nervous influx that the relation pointed out appears to be made manifest. In support of this opinion I will indicate:— (_a_) The attraction and repulsion which the palm of the hand exercises to the almost total exclusion of the back of the hand; (_b_) The diverse sensations which I have analysed; (_c_) The influence of the mental condition and dispositions of the experimenters;