“I remember a case of a woman named Jenny,” Dr. Lytton mused aloud. “Do you mind sitting closer so I can see you, Julien? It’s rather difficult talking to an apparition. Thanks.... Now we’ll discuss the strange case of Florence Ballau. I’ll give you the groundwork. We’ll be able to operate in the open, then. And I shall need your help. Yes, you can help me, Julien.”

“Go on,” De Medici muttered.

“About Jenny,” Dr. Lytton resumed. “Well, she was the mother of a three-year-old boy who, while playing, slipped out of the window of their flat. As she came walking back from the grocery store, Jenny looked up. She saw her child hanging by his fingers from the window four stories above the ground. She stood powerless and transfixed while his little fingers slowly gave way. She watched him slip ... slip, and then his body shot to the ground and was smashed to a pulp before her eyes. And here we have a logical cause for dual personality.

“The shock was terrific for the mother. It split her mind. And an abnormal condition developed. Her little son fell to his death eight years ago and Jenny is now in an asylum. I’ve studied her carefully. She is the ideal dual personality case. You see, Julien, nothing inherited, no phantoms, no mysterious impulses. Merely a shock that split the mind into two compartments. She presents the following symptoms. She will be engaged, for instance, in sewing or in conversation. Suddenly she ceases her work. She stands up. Her eyes lift. And for the minutes that follow she lives over again the awful scene of her little son’s death, carrying out in every detail the tragedy of the thing. And during the minutes the hallucination endures she goes through the scene with all the power of an accomplished emotional actress.

“Yes, I’ve watched her. While this drama is in progress she is perfectly unconscious of the actual things happening around her. She hears nothing that is said and sees nothing but the imaginary scene which she is reliving. This phenomenon, which is technically called somnambulism, will end as suddenly as it begins, and Jenny will return to her former occupation, absolutely unaware of the fact that it has been interrupted. You see how different your alleged and artificial case of fancied obsession is, Julien. You remember too much. The vision of Francesca is in your mind now—the thing you fancied you saw. Therefore you are not a victim of disassociation. If you’re a man of evil at all, it is you who sit here and not a hidden, unknown you that walks in the dark places of your subconscious.”

Dr. Lytton leaned forward and placed his hand on De Medici’s knee.

“If Jenny is questioned during her apparently normal intervals,” he said, “it will be found that she has not only entirely forgotten everything that happened during her somnambulism, but that the whole tragedy of her boy’s death has completely disappeared from her conscious mind. She remembers nothing of the minutes she stood watching her son slipping from the window ledge. And if you press her she’ll discuss his death vaguely and indifferently as if it were the death of someone else’s child. She’ll say, ‘Oh, he just died, that’s all.’ And reveal no interest or emotion whatsoever. Yet concerning all other things of her past life she has a rather keen memory.

“This curious localized loss of memory or amnesia is found in some cases. In other dual personality cases we have a complete loss of memory of all events preceding the shock that produced the disassociation. So you see, science absolves you, Julien.”

De Medici nodded.

“Now we come to Florence Ballau. A high-strung, vivid temperament,” continued Dr. Lytton. “The letter signed Floria and decorated with the dagger reveals one thing. Its writer is suffering from delusions of persecution. Persecutory delusions are a common form of mental disorder. We all have them more or less. Floria is the terrified and persecuted thing that dwells in the soul of Florence Ballau. At times this terrified thing usurps the body of Miss Ballau and lives its own mysterious life. As in the case of Jenny it is not an inherited phenomenon. It was induced by shock of some sort. Florence may be dimly aware of the change after she returns to herself. More likely, however, she is merely distracted, depressed, and suffers from a sense of bewilderment.”