A favorite demonstration of profound hypnosis made in public exhibitions is the production of catalepsy. The subject is brought into this condition by the method explained in Chapter VII (Degrees Of Hypnosis), and when the subject is perfectly rigid, his body is lifted and placed in such a position as to cause the head to rest upon one chair, while the feet rest upon another, making of it a sort of human bridge, upon which the operator may place weights, or upon which he may stand. Such an act is positive evidence of hypnosis, for it cannot be performed under natural conditions.

Very frequently we hear of large stones being placed upon the chest of a cataleptic person, and then being broken by a sledge hammer. This can be done, but it must be remembered that hypnosis does not alter the structures of bones and muscles, and serious physical injury might follow such an uncalled-for exhibition.

In this connection it is well to repeat the caution against forcing a subject into a lethargic trance except for purely scientific purposes. Operators have rendered their subjects almost lifeless for days and weeks, and in Oriental countries self-hypnotists have thrown themselves into trances lasting for months.