Now my nerve-fluid moves by pulsatory movements, as move all other media, and these movements sustain to those of your nerve-fluid commensurable or incommensurable relations; and you will find that the law of musical harmony, by which one of two strings having the same tension communicates its motion to the other, is the law which determines the harmony between my nerve-system and yours. I am constituted to speak upon a certain key, like an instrument. My nerve-vibrations undulate to that key, and when I am in perfect health, there is perfect harmony in my system. Your nerve-undulations are perhaps tuned on a different key, and if you are positive to me, my nerve-undulation will not move yours, nor yours mine, but they will resist each other like two strings unequally tuned. So my nerve-vibration will not communicate its undulations to you, nor will yours communicate its undulations to me, unless we happen to be upon the same key, or in harmonic or commensurable relations with one another. But in order to get our nerve-systems to undulate one upon the other, I must either become negative to you or you must become negative to me. If I relax the key of my nerve-vibration, I shall change them until my nerve-system undulates in harmony with your nerve-system; and I being negative and you positive, you undulate to my key, and we get nerve-sensations between us without any sign. The individual in mesmerizing his subject becomes positive, and he will succeed in mesmerizing that subject just as soon as he brings about a harmony of nerve-vibration, so that the nerve-vibrations of both are alike. The condition is that the operator places himself in a positive position, while the subject must become negative, by allowing his nerves to become relaxed; then the operator commences by a strong effort to undulate, so to speak, his nerve-influence or forces upon the medium, until the medium sinking down comes to his key; and then he by his forces insulates the system, and the individual passes rapidly into the condition of mesmerism; but do any thing to disturb that medium, so as to make the points of nerve-tension unyielding, and the operator may work till doomsday in vain. It is not till the points have yielded and the vibrations harmonize with his that he can produce the effect upon the medium. This is on the same principle with the phenomena exhibited in experiments with the string, which is a type of the law of communication in every sphere—the vibration of the string represents the entire law.