The initial point of our knowledge of hypnotism is the fact that we can practically observe that it is possible for one person to mentally control the thoughts and actions of another person; and that the person controlled cannot ordinarily regain his individual power to think and act for himself until permitted to do so by the person controlling him.

It is well to analyze this fact and satisfactorily explain it to ourselves, that we may have a basis upon which to build our knowledge of hypnotic phenomena. By way of illustration let us consider one of the simplest examples.

A hypnotist has seated before him a subject with whom he intends to experiment. Apparently there is little difference between them; both seem sound in mind and body; still one assumes at once to direct the other, who obeys. This may be by agreement; but evidently no lot was cast as to who should command and who should obey. It seems to have been decided by mutual consent, or rather not to have been decided at all, but simply to have been taken for granted. One assumes the role of operator and consequently the other becomes at once the subject. The one asserts a superiority and the other instantly manifests a greater or less degree of submission. No words to this effect have been spoken and no physical force has been employed to produce it, nevertheless it is realized by all parties interested.

The operator directs the subject to assume certain positions, which are assumed at once. He says but few words; but every request made is instantly obeyed. The subject is able to voluntarily withdraw his attention and refuse obedience, but chooses to, or rather simply does, remain and follow whatever instruction is given him..

The operator makes certain movements and then utters assertions which are heard and believed by the subject, who manifestly has relinquished all independence. He believes the most absurd statements and at a mere suggestion from the operator performs all manner of actions and zealously applies himself to any task assigned him, real or imaginary. In fact, whatever the operator wills and suggests that the subject performs.

Such is an example of ordinary hypnotism, where the operator has mentally influenced the thoughts and actions of the subject; and we must establish in our own minds a satisfactory explanation of how the influence was obtained and obedience enforced. The subject's transition from voluntary submission to involuntary obedience was apparently gradual; yet there must have been an instant when the change was made.

We can, by way of illustration, compare this performance to the gradual addition of weights to one side of a pair of scales to counteract the pressure exerted by some heavy substance on the other side. Little by little additional weights are added until the balancing point is reached and then passed. Similarly, the will of the operator gradually overcomes the resistance of the subject and when the balancing point has been passed there is no more resistance and the subject is hypnotized.

To carry the illustration further, when the profound stage of hypnotic sleep has been produced, the operator's will may be compared to one side of the scale completely loaded down with weights; while the subject's will is nothing in comparison. It makes no impression, whatever, and does not enter into the question of balance.

In testing a new subject it is always uncertain just how much will power may be necessary to cause submission; and the act of hypnotizing is usually gradual. When a subject has been thoroughly controlled, it is comparatively easy to again hypnotize him; or, carrying out the illustration, knowing the pressure upon one side of the scale, the weights to counterbalance it may be applied at once.

Experience soon demonstrates to an operator the degree of effort he must exert to hypnotize a subject; and the most expert hypnotist occasionally meets with persons whom he quickly perceives to be beyond his powers of influence.