The variety known as the ambulatory type, where the patient suddenly loses all knowledge of his own identity and of the past and takes himself off, leaving no trace or clue, is the variety which the present case of Miss Blackwell seems to suggest.
There followed a number of most interesting cases and an elaborate argument by the writer to show that Betty Blackwell was a victim of this psychological aberration, that she was, in other words, "a vanisher."
I laid down the paper with a questioning look at Kennedy.
"As a scientist," he replied deliberately, "the theory, of course, does appeal to me, especially in the ingenious way in which that writer applied it. However, as a detective"—he shook his head slowly—"I must deal with facts—not speculations. It leaves much to be explained, to say the least."
Just then the door buzzer sounded and Carton himself sprang to answer it.
"That's Mrs. Blackwell now—her mother. I told her that I was going to take the case to you, Kennedy, and took the liberty of asking her to come up here to meet you. Good-afternoon, Mrs. Blackwell. Let me introduce Professor Kennedy and Mr. Jameson, of whom I spoke to you."
She bowed and murmured a tremulous greeting. Kennedy placed a chair for her and she thanked him.
Mrs. Blackwell was a slender little woman in black, well past middle age. Her face and dress spoke of years of economy, even of privation, but her manner was plainly that of a woman of gentle breeding and former luxury. She was precisely of the type of decayed gentlewoman that one meets often in the city, especially at some of the middle-class boarding-houses.
Deeply as the disappearance of her daughter had affected her, Mrs. Blackwell was facing it bravely. That was her nature. One could imagine that only when Betty was actually found would this plucky little woman collapse. Instinctively, one felt that she claimed his assistance in the unequal fight she was waging against the complexities of modern life for which she had been so ill prepared.
"I do hope you will be able to find my daughter," she began, controlling her voice with an effort. "Mr. Carton has been so kind, more than kind, I am sure, in getting your aid. The police seem to be able to do nothing. They make out reports, put me off, tell me they are making progress—but they don't find Betty."