There is, then, a gradual preparation required, at least for the majority of operators. Does this preparation consist in a modification that takes place in the operator, or in the inert body on which he acts, or in both? In order to resolve this problem, experimenters who had been practicing at one table went over to another, operating on which they found their full power unabated. The preparation therefore consists in a modification that takes place in the individuals, and not in the inert body.[58] This modification occurring in individuals is dissipated rather rapidly, especially when the chain of experimenters is broken. _Inner Development of the Operators._--It is only after a certain period of waiting that the operators, who have not so far acted, cause even the easiest movement,--that of rotation with contact. It is during this time that the force, or the conditions determining the manifestation of the force, develop themselves. From that time on, the developed force has nothing to do but to increase. That which takes place, therefore, in this time of waiting, is a very important thing to be considered. We already know that it is the operators themselves who are modified. But what is it that takes place within them? It must be that a kind of activity is set up in the organism, an activity which ordinarily requires the intervention of the will. This activity, this work, is accompanied by a certain fatigue. The action is not aroused in all operators with equal ease and promptness. There are even persons (the author estimates their number at one in ten) in whom it appears that it cannot be produced at all. In the midst of this great diversity of natural aptitudes, it is observed that children "can secure obedience from the table just like grown folks." Nevertheless, children do not magnetize. Thus, although several facts seem to show that magnetizers (or mesmerizers) have frequently a strong power over the tables, yet one cannot admit the identity of magnetic power and power over the tables; the one is not the measure of the other. Only, the magnetic power would constitute (or presume) a favorable subjective condition. A will simple and strong, animation, high spirits, the concentration of the thought upon the work to do, good bodily health, perhaps the very physical act of turning around the table, and, finally, everything that can contribute to unity of will-power among the experimenters,--all these things help to make efficacious the commands addressed to the table with force and authority. The tables (says M. de Gasparin) "wish to be handled gaily, freely, with animation and confidence; they must be humored at the start with amusing and easy exercises." The first condition necessary for success with the table is good health and the second, confidence.