Impressed by the recurrence of this hallucination, the physician in charge of the case questioned the boy's mother as to a possible explanation for his believing the devil was chasing him. Reluctantly, the mother confessed that one day when her little son had been unruly she had warned him that if he did not behave the devil would come for him. It was the night after she had thus foolishly threatened him that he had his first attack of _pavor nocturnus_. Armed with this knowledge, the physician began a course of treatment which effected a cure in a week. It properly included tonics and dieting to overcome the indigestion and other physical ailments caused by the strain of nervous excitement. But its principal feature was treatment by suggestion, to dislodge from the boy's mind his morbid fear of the devil. Anything which causes the instinct of fear to function abnormally may act with decisive force in bringing on night terrors. The telling of ghost stories and other gruesome tales of the supernatural has been productive of much harm in this respect. And, as brought out in the preceding chapter, cases of night terrors have similarly been traced to the hearing or reading by children of fairy tales containing elements of the horrible. The child that is supersensitive may be so impressed by these elements as to brood over them and, in waking reverie, apply them to himself. Thus they get fixed in the mind, to disturb and alarm it, and, eventually, to find expression in dreams of so unpleasant a character that night terrors may be a result. With the night terrors left untreated psychologically, subsequent nervous ailments, perhaps lifelong invalidism, may further penalise the hapless victim of parental thoughtlessness. I am reminded of a certain patient of Doctor Sidis's, a woman afflicted with neurotic ills up to the age of sixty, and, when she first consulted the New England specialist, displaying a most complicated set of disease symptoms. She had kidney trouble, stomach trouble, frequent headaches, insomnia, and general nervousness. In especial, she suffered from an obsessive fear of becoming insane. This fear, at times, was so extreme that she would walk up and down her room night after night, "like an animal in a cage," to use Doctor Sidis's expressive phrase. Repeated examinations by different physicians had failed to bring to light any evidences of organic disease of stomach, kidneys, or brain, and a diagnosis of hysteria had finally been made. Consequently, it became Doctor Sidis's special task to endeavour to get at these latent memory-images that had acted with disintegrative power on the mental and bodily processes, recall them to conscious remembrance, and, by suggestive treatment, rob them of their disease-producing potency.