The article was brief: 

Mysterious disappearances, such as that of Betty Blackwell, have alarmed the public and baffled the police before this—­ disappearances that have in their suddenness, apparent lack of purpose, and inexplicability much in common with her case.  Leaving out of account the class of disappearances for their own convenience—­embezzlers, blackmailers, and so forth—­there is still a large number of recorded cases where the subjects have dropped out of sight without apparent cause or reason and have left behind them untarnished reputations and solvent back accounts.  Of these, a small percentage are found to have met with violence; others have been victims of suicidal mania, and sooner or later a clue has come to light which has established the fact.  The dead are often easier to find than the living.

Of the remaining small proportion, there are on record, however, a number of carefully authenticated cases where the subject has been the victim of a sudden and complete loss of memory.

This dislocation of memory is a variety of aphasia known as amnesia, and when the memory is recurrently lost and restored, we have alternating personality.  The Society for Psychical Research and many eminent psychologists, among them the late William James, Dr. Weir Mitchell, Dr. Hodgson of Boston, and Dr. A. E. Osborn of San Francisco, have reported many cases of alternating personality.

Studious efforts are being made to understand and to explain the strange type of mental phenomena exhibited in these cases, but as yet no one has given a clear and comprehensive explanation of them.  Such cases are by no means always connected with disappearances, and exhaustive studies have been made of types of alternating personality that have from first to last been carefully watched by scientists of the first rank.

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.”