Take one string whose points of tension are unyielding, and another whose points of tension are yielding; then cause one of them to undulate, and it will impart its motion to the atmosphere, when the atmosphere will strike upon the other; and if it have the same points of tension that the other has, it will undulate; but if it have not the same tension, it will receive the influence of the atmosphere, the tendency of which will be to depress it and bring it to its own vibration; thus eventually the two strings will be made to harmonize. So when we sit down to mesmerize a person, he may be so positive that we do not at first succeed, perhaps, in producing the least impression upon him. We try again and again, and at last succeed in controlling the nerve-system, and through that the mental system of the subject. We are each time we try reducing the nerve-system to our key or standard, and the moment it is reduced to that point, the subject is under the operator’s control, and not till then. When I speak of the harmonic action of one system upon another, it will be perceived that I speak of the relative measure or length of the nerve-undulation which passes between one mind and another. In the nerve-plane there is this method of addressing the nervous perceptions by external means—by language, by signs, by pantomimic representations. And there is the internal method corresponding to inspiration, which consists in coming into nervous sympathy and receiving nervous sensations one from another. A sensitive person looking upon a wound shrinks from beholding the sight, and there are real sensations experienced in his nervous system which have been produced, not because a nerve-influence has acted upon him, but because he has seen the wound. The impression first fell upon his conscious perceptions, and then went to his feelings, which is analogous to the principle that the idea first comes into the thought, and thence reaches the feelings.