Unconscious Muscular Action, produced during an especially Nervous Condition.—So long as only movements with contact were known, in which the movement observed was one of those which muscular action might produce, explanations based on the hypothesis of unconscious muscular action were certainly sufficient and much more probable than all the other explanations which had been up to that time proposed.
From this point of view (entirely physiological) it is settled that we must distinguish between the effort which a muscle exerts and the consciousness we have of this effort. It will be remembered that there exist in the human organism a great number of muscles that habitually exert considerable effort without our being in the slightest degree aware of it. It has been pointed out that muscles exist whose contractions are perceptible by us in a certain state of the system and unperceived in another state. It is therefore conceivable that the muscles of our limbs might as an exceptional thing, exhibit the same phenomenon. The preparation for the movement of the table, the special kind of reaction that takes place at this interval of waiting, put the nervous system into a particular condition in which certain muscular movements may take place in an unconscious manner.
But, evidently, this theory is not sufficient to account for movements without contact, nor those that take place in such a way that muscular action could not produce them. It is therefore these two classes of movements which must serve as the basis of new experiments and as the foundation of a new theory.
How also explain the very peculiar and truly inconceivable character of the movements of the table?—this starting to move, so insensible, so gentle, so different from the abruptness characteristic of the impetus given by mechanical force; these levitations so spontaneous, so energetic, which leap up to meet the hands; these dances and imitations of music which you would in vain attempt to equal by means of the combined and voluntary action of the operators; these little raps succeeding the loud ones, when the command is given, the exquisite delicacy of which nothing can express. Several times when someone asked a so-called spirit his age, one of the legs of the centre-table lifted up and rapped 1, 2, 3, etc. Then the movement was accelerated. Finally, the three legs beat a kind of drum-roll so rapid that it was impossible to count, and which the most skilful could never succeed in imitating. On another occasion, under the contact of hands, the table was turning upon three legs, upon two, upon a single one; and, in this last position, changed feet, throwing its weight first upon one and then upon another with great ease, and with nothing abrupt or jerky in its motions. Neither the experimenters nor their most eminent opponents would ever be able to imitate mechanically this dance of the table, and, above all, the whirling pirouettes and changes of feet.
Electricity.—Many have tried to explain the movements of tables by electricity. Even supposing that they involve the very abundant production of this agent, no known effect of electricity would account for the movement of the tables. But, in fact, it is easy to show that there is no electricity produced; for, when a galvanometer was interposed in the chain, no deviation of the needle took place. The electrometer remains as indifferent to the solicitations of the tables as does the mariner's compass.
Nervo-magnetism.—There is certainly some analogy between several phenomena of nervo-magnetism and those of the tables. Those passes which seem to favor balancing without contact; the motion imparted by the chain to this man whom they cause to turn about (unless, indeed, there is in this some effect of the imagination); finally, the power that many mesmerizers exert over the tables—all this seems to indicate a kinship between the two orders of phenomena. But, since the laws of nervo-magnetism are little known, there is no conclusion to be drawn from this, and it seems to me preferable, for the present, to study separately the phenomena of tables, which are better adapted to the experiments of the physicist, and which, well studied, will render more service to nervo-magnetism than it could receive in a long time from this obscure branch of physiology.
Thury next touches upon M. de Gasparin's theory of fluidic action. Being certain that he accurately understands this theory, he gives a résumé of it in the following items:
1. A fluid is produced by the brain, and flows along the nerves.
2. This fluid can go beyond the limits of the body; it can be emitted.
3. Under the influence of the will, it can move hither and thither.