“Are you indeed?” I exclaimed.

“I studied in Paris for a year under Charcot at the Salpêtrière Hospital.* If Uncle Augustus had possessed the funds, he would certainly have set me up in Cavendish Square, and my expertise would thus be certified geographically. I am afraid Baker Street is the revered locus of criminal detection, not of the cure of mental disease. At present I subsist on referrals: the nervous, the hypochondriacal, and the merely sick. And of course, the occasional stabbing comes my way.”

“Yes, well,” coughed Holmes, “as it happens that is just the matter in which I require your assistance.”

“That is wonderful news!” Dr. Agar grinned. “I was burning with curiosity, but as a gentleman, I could hardly ask. What sort of assistance may I render?”

“Dr. Watson’s Medical Directory informed me you were a specialist in nervous disorders, and a glance at your shelves tells me you may be just the expert I require. Textbook of Brain Disorders, Mental Pathology and Therapeutics, Psychopathia Sexualis*—if you are the doctor your library proclaims, you could be of the greatest use.”

Holmes related briefly the circumstances which led to his grisly introduction to Dr. Agar. When he finished, the doctor nodded with an expression of deepest interest.

“I have, of course, followed the Ripper’s crimes very closely. I had an inkling from the press reports that it was his work I stitched up the other night. But let me understand you, sir—do you seek aid that is in some way psychological?”

“I do,” confirmed Holmes. “I am a consulting detective, Dr. Agar, and as such many branches of study come within my sphere, the majority of which deal with gathering and interpreting hard evidence. However, I believe the Ripper may be a variety of criminal I have never before pursued, and one against whom hard evidence is of alarmingly little use. My practice is based upon the fact that, although a given crime may appear unique, to the connoisseur of criminal history, it nearly always follows an established pattern. In this case, the template was so very rare that it took me some time to identify it. But since the events of the thirtieth, I begin to know this fellow better. The double murder eroded his mask in a profound fashion. It appears we must understand that slaying these women is a pleasure second only to afterwards ripping them to pieces.”

I felt a growing revulsion at the conversation, but Dr. Agar appeared profoundly intrigued. “He seeks out women who have wronged him and enacts these terrible crimes out of sheer hatred?” I questioned.

Holmes shook his head. “I do not believe he knows them. It is my working hypothesis that this man kills perfect strangers. In fact, I have been led to believe that we are on the trail of a complete madman who is for all appearances an ordinary person.”

I stared at him aghast. “I could well believe that the fiend is mad,” I protested, “but what you suggest is impossible. There must be another motive behind the deaths of these women. The mad do not walk among the sane unremarked.”

“Do they not?” he queried, one brow tilted toward the ceiling.

“No,” I insisted irritably. “The merely eccentric are as sane as you or I, but as for a man who butchers the most pitiable of our populace without reason or foreknowledge—can you seriously believe such malice could go about the business of day-to-day life without exciting alarm?”

“Do not ask me. That is what I wish to inquire of Dr. Agar,” Holmes replied, turning the force of his steely gaze upon the psychologist standing before the dwindling fire. “Is it possible, in your professional opinion, for a madman to enact a faultless pretense of rational humanity?”

Dr. Agar moved to his bookshelf and selected a slim volume. “I begin to guess at your meaning, Mr. Holmes. You refer to the London Monster.”

Holmes swiftly indicated a passage from his commonplace book. “I refer not only to the London Monster, although he plays a telling role. Nearly a century ago—April seventeen eighty-eight, London: first appearance of the London ‘Monster.’ Approximately fifty women knifed on the streets between the years of eighty-eight and ninety. Suspect never caught. Mark that, Watson. Moving to the Continent; Innsbruck, eighteen twenty-eight: multiple women approached and stabbed with a common pocketknife. Case never closed. Bremen, eighteen eighty: a hairdresser slashed the breasts of no fewer than thirty-five women in broad daylight before he was apprehended. All are examples of what I believe could be termed a deeply morbid erotic mania.”

“Your chain of reasoning is rather terrifying, sir,” said Dr. Agar.

“What chain of reasoning, Holmes?” I questioned apprehensively.

“If I can discover a link connecting the victims—shared knowledge of a secret is an excellent example—the hypothesis will, blessedly, shatter,” he returned. “But I have repeated to myself Cui bono? until I can feel the words burned upon my brain, and the only answer is No one. For now, it is clear that any man committing so many motiveless crimes must necessarily be mad. And yet, in order to continue freely committing them…”

“The culprit cannot have appeared to be mad,” finished Dr. Agar.

“So I put it to you, Dr. Agar,” Holmes concluded grimly. “Is such a thing possible?”

“It is a very difficult question to answer with any degree of assurance,” he replied carefully. “After all, is mental illness a sickness of the soul, degeneracy of stock, or a defect of the brain? What you propose is an entirely new form of madness—a monomania lurking beneath a rational mind, aiding itself and disguising itself. Your idea comes closer to the classical definition of pure malevolence than any maniac who lashes out with a frenzied knife. You speak of a complete moral degeneracy, assisted by an affable exterior and a shrewd intelligence.”

“Precisely,” said Sherlock Holmes.

“I’m afraid I think it entirely possible,” Dr. Agar replied.

“Then there is nothing for it,” said my friend. “My thanks for your assistance. If you will excuse me, I have a deal of work ahead of me. Payment for your past services is there, on the table.”

Dr. Agar quickly attempted to return the notes. “Mr. Holmes, as your neighbour, I would not dream of exacting payment over an emergency.”

“Then consider it a consulting fee,” my friend smiled. “This way, Watson. We’ll not intrude further upon Dr. Agar’s time.”

“Thank you, Mr. Holmes,” said the affable young fellow at the door. “If you should feel the need to intrude again, I beg that you will not hesitate! I treated three patients this afternoon—two for insomnia, and one for an ill-disguised preoccupation with opiates. Your visit has quite redeemed the day.”*

We waved to Dr. Agar and strolled the few steps back to our own door.

“You appear disturbed, Dr. Watson,” Holmes remarked.

“I cannot readily believe such men exist outside the realm of fiction designed to horrify the reader,” I admitted, casting about for my key.

“It is difficult to fathom, I know, for I required weeks to even consider such a nightmare possible.”

“And you are sure our man is of a kind?” I persisted as we made our way up the stairs.

“I have no doubt of it.”

“I cannot begin to think what steps you will take. It is a monster you describe, Holmes.”

“He is neither a monster nor a beast, but something far more dangerous. I fear that men, when possessed of both utter depravity and absolute conviction, are far more deadly than either. And I begin to fear that such men are nearly impossible to find. But I’ll do it, Watson. I shall have him. I swear to you it shall be done.” Holmes nodded a good night and then, without another word, vanished into the confines of his room.