It was through experiments on hypnotized subjects that scientists first learned of the suggestibility of the subconscious mind. In hypnosis a person can be made to believe almost anything and to do almost anything compatible with the safety and the moral sense of the individual. The instinct of self-preservation will not allow the most deeply hypnotized person to do anything dangerous to himself; and the moral complexes, laid in the subconscious, never permit a person to perform in earnest an act of which the waking moral sense would disapprove. Within these limits, a person in the dissociated hypnotic state can be made to accept almost any suggestion. We found in the last chapter how open to suggestion is a person in normal sleep. Of the dissociation of hysteria we shall have occasion to speak in later chapters. Although all these special states heighten suggestibility, we must not forget how susceptible each of us is in his normal waking state. =Living Its Faith.= All this gathers meaning only when we realize that ideas are dynamic. They always tend to work themselves out to fulfilment. The subconscious no sooner gets a conviction than it tries to act it out. Of course it can succeed only up to a certain limit. If it believes the stomach to have cancer, it cannot make cancer, but it can make the stomach misbehave. One of my patients, on hearing of a case of brain-tumor immediately imagined this to be her trouble, and developed a pain in her head. She could not manufacture a tumor, but she could manufacture what she believed to be the symptoms. There was another patient who was supposed to have brain-tumor. This young woman seemed to have lost almost entirely the power to keep her equilibrium in walking. Her center of gravity was never over her feet, but away out in space, so that she was continually banging from one side of the room to the other, only saving herself from injury by catching at the wall or the furniture with her hands. Several physicians who had been interested in the case had found the symptoms strongly suggestive of brain-tumor. There were, however, certain unmistakable earmarks of hysteria, such as childlike bland indifference to the awkwardness of the gait which was a grotesque caricature of several brain and spinal-cord diseases, with no accurate picture of any single one. This was evidently a case, not of actual loss of power but a dissociation of the memory-picture of walking. The patient was a trained nurse and knew in a general way the symptoms of brain-tumor. When the suggestion of brain-tumor had fixed itself in her mind she was able subconsciously to manufacture what she believed to be the symptoms of that disease.