It was dusk, on the evening of December 7, 1906, when I first encountered Sir John Harmon. At the moment of his entrance I was standing over the table in my study, a lighted match in my cupped hands and a pipe between my teeth. The pipe was never lit.

I heard the lower door slam shut with a violent clatter. The stairs resounded to a series of unsteady footbeats, and the door of my study was flung back. In the opening, staring at me with quiet dignity, stood a young, careless fellow, about five feet ten in height and decidedly dark of complexion. The swagger of his entrance branded him as an adventurer. The ghastly pallor of his face, which was almost colorless, branded him as a man who has found something more than mere adventure.

“Doctor Dale?” he demanded.

“I am Doctor Dale.”

He closed the door of the room deliberately, advancing toward me with slow steps.

“My name is John Harmon--Sir John Harmon. It is unusual, I suppose,” he said quietly, with a slight shrug, “coming at this late hour. I won’t keep you long.”

He faced me silently. A single glance at those strained features convinced me of the reason for his coming. Only one thing can bring such a furtive, restless stare to a man’s eyes. Only one thing--fear.

“I’ve come to you. Dale, because--” Sir John’s fingers closed heavily over the edge of the table--”because I am on the verge of going mad.”

“From fear?”

“From fear, yes. I suppose it is easy to discover. A single look at me...”

“A single look at you,” I said simply, “would convince any man that you are deadly afraid of something. Do you mind telling me just what it is?”

He shook his head slowly. The swagger of the poise was gone; he stood upright now with a positive effort, as if the realization of his position had suddenly surged over him.

“I do not know,” he said quietly. “It is a childish fear--fear of the dark, you may call it. The cause does not matter; but if something does not take this unholy terror away, the effect will be madness.”

I watched him in silence for a moment, studying the shrunken outline of his face and the unsteady gleam of his narrowed eyes. I had seen this man before. All London had seen him. His face was constantly appearing in the sporting pages, a swaggering member of the upper set--a man who had been engaged to nearly every beautiful woman in the country--who sought adventure in sport and in night life, merely for the sake of living at top speed. And here he stood before me, whitened by fear, the very thing he had so deliberately laughed at!

“Dale,” he said slowly, “for the past week I have been thinking things that I do not want to think and doing things completely against my will. Some outside power--God knows what it is--is controlling my very existence.”

He stared at me, and leaned closer across the table.

“Last night, some time before midnight,” he told me, “I was sitting alone in my den. Alone, mind you--not a soul was in the house with me. I was reading a novel; and suddenly, as if a living presence had stood in the room and commanded me, I was forced to put the book down. I fought against it, fought to remain in that room and go on reading. And I failed.”

“Failed?” My reply was a single word of wonder.

“I left my home: because I could not help myself. Have you ever been under hypnotism, Dale? Yes? Well, the thing that gripped me was something similar--except that no living person came near me in order to work his hypnotic spell. I went alone, the whole way. Through back streets, alleys, filthy dooryards--never once striking a main thoroughfare--until I had crossed the entire city and reached the west side of the square. And there, before a big gray town-house, I was allowed to stop my mad wandering. The power, whatever it was, broke. I--well, I went home.”

Sir John got to his feet with an effort, and stood over me.

“Dale,” he whispered hoarsely, “what was it?”

“You were conscious of every detail?” I asked. “Conscious of the time, of the locality you went to? You are sure it was not some fantastic dream?”

“Dream! Is it a dream to have some damnable force move me about like a mechanical robot?”

“But ... You can think of no explanation?” I was a bit skeptical of his story.

He turned on me savagely.

“I have no explanation. Doctor,” he said curtly. “I came to you for the explanation. And while you are thinking over my case during the next few hours, perhaps you can explain this: when I stood before that gray mansion on After Street, alone in the dark, there was murder in my heart. I should have killed the man who lived in that house, had I not been suddenly released from the force that was driving me forward!”

Sir John turned from me in bitterness. Without offering any word of departure, he pulled open the door and stepped across the sill. The door closed, and I was alone.

That was my introduction to Sir John Harmon. I offer it in detail because it was the first of a startling series of events that led to the most terrible case of my career. In my records I have labeled the entire case “The Affair of the Death Machine.”

Twelve hours after Sir John’s departure--which will bring the time, to the morning of December 8--the headlines of the Daily Mail stared up at me from the table. They were black and heavy: those headlines, and horribly significant. They were:

FRANKLIN WHITE Jr. FOUND MURDERED

Midnight Marauder Strangles Young Society Man in West-End Mansion

I turned the paper hurriedly, and read:

Between the hours of one and two o’clock this morning, an unknown

murderer entered the home of Franklin White, Jr., well known

West-End sportsman, and escaped, leaving behind his strangled

victim.

Young White, who is a favorite in London upper circles, was

discovered in his bed this morning, where he had evidently lain

dead for many hours. Police are seeking a motive for the crime,

which may have its origin in the fact that White only recently

announced his engagement to Margot Vernee, young and exceedingly

pretty French débutante.

Police say that the murderer was evidently an amateur, and that he

made no attempt to cover his crime. Inspector Thomas Drake of

Scotland Yard has the case.

There was more, much more. Young White had evidently been a decided favorite, and the murder had been so unexpected, so deliberate, that the Mail reporter had made the most of his opportunity for a story. But aside from what I have reprinted, there was only a single short paragraph which claimed my attention. It was this:

The White home is not a difficult one to enter. It is a huge gray

town-house, situated just off the square, in After Street. The

murderer entered by a low French window, leaving it open.

I have copied the words exactly as they were printed. The item does not call for any comment.

But I had hardly dropped the paper before she stood before me. I say “she”--it was Margot Vernee, of course--because for some peculiar reason I had expected her. She stood quietly before me, her cameo face, set in the black of mourning, staring straight into mine.

“You know why I have come?” she said quickly.

I glanced at the paper on the table before me, and nodded. Her eyes followed my glance.

“That is only part of it, Doctor,” she said. “I was in love with Franklin--very much--but I have come to you for something more. Because you are a famous psychologist, and can help me.”

She sat down quietly, leaning forward so that her arms rested on the table. Her face was white, almost as white as the face of that young adventurer who had come to me on the previous evening. And when she spoke, her voice was hardly more than a whisper.

“Doctor, for many days now I have been under some strange power. Something frightful, that compels me to think and act against my will.”

She glanced at me suddenly, as if to note the effect of her words. Then:

“I was engaged to Franklin for more than a month, Doctor: yet for a week now I have been commanded--commanded--by some awful force, to return to--to a man who knew me more than two years ago. I can’t explain it. I did not love this man; I hated him bitterly. Now comes this mad desire, this hungering, to go to him. And last night--”

Margot Vernee hesitated suddenly. She stared at me searchingly. Then, with renewed courage, she continued.

“Last night, Doctor, I was alone. I had retired for the night, and it was late, nearly three o’clock. And then I was strangely commanded, by this awful power that has suddenly taken possession, of my soul, to go out. I tried to restrain myself, and in the end I found myself walking through the square. I went straight to Franklin White’s home. When I reached there, it was half past three--I could hear Big Ben. I went in--through the wide French window at the side of the house. I went straight to Franklin’s room--_because I could not prevent myself from going_.”

A sob came from Margot’s lips. She had half risen from her chair, and was holding herself together with a brave effort. I went to her side and stood over her. And she, with a half crazed laugh, stared up at me.

“He was dead when I saw him!” she cried. “Dead! Murdered! That infernal force, what ever it was, had made me go straight to my lover’s side, to see him lying there, with those cruel finger marks on his throat--dead, I tell you, I--oh, it is horrible!”

She turned suddenly.

“When I saw him,” she said bitterly, “the sight of him--and the sight of those marks--broke the spell that held me. I crept from the house as if I had killed him. They--they will probably find out that I was there, and they will accuse me of the murder. It does not matter. But this power--this awful thing that has been controlling me--is there no way to fight it?”

I nodded heavily. The memory, of that unfortunate fellow who had come to me with the same complaint was still holding me. I was prepared to wash my hands of the whole horrible affair. It was clearly not a medical case, clearly out of my realm.

“There is a way to fight it,” I said quietly. “I am a doctor, not a master of hypnotism, or a man who can discover the reasons behind that hypnotism. But London has its Scotland Yard, and Scotland Yard has a man who is one of my greatest comrades...”

She nodded her surrender. As I stepped to the telephone, I heard her murmur, in a weary, troubled voice:

“Hypnotism? It is not that. God knows what it is. But it has always happened when I have been alone. One cannot hypnotise through distance...”

And so, with Margot Vernee’s consent, I sought the aid of Inspector Thomas Drake, of Scotland Yard. In half an hour Drake stood beside me, in the quiet of my study. When he had heard Margot’s story, he asked a single significant question. It was this:

“You say you have a desire to go back to a man who was once intimate with you. Who is he?”

Margot looked at him dully.

“It is Michael Strange,” she said slowly. “Michael Strange, of Paris. A student of science.”

Drake nodded. Without further questioning he dismissed my patient; and when she had gone, he turned to me.

“She did not murder her sweetheart, Dale” he said. “That is evident. Have you any idea who did?”

And so I told him of that other young man. Sir John Harmon, who had come to me the night before. When I had finished. Drake stared at me--stared through me--and suddenly turned on his heel.

“I shall be back, Dale,” he said curtly. “Wait for me!”

Wait for him! Well, that was Drake’s peculiar way of going about things. Impetuous, sudden--until he faced some crisis. Then, in the face of danger, he became a cold, indifferent officer of Scotland Yard.

And so I waited. During the twenty-four hours that elapsed before Drake returned to my study, I did my best to diagnose the case before me. First, Sir John Harmon--his visit to the home of Franklin White. Then--the deliberate murder. And, finally, young Margot Vernee, and her confession. It was like the revolving whirl of a pinwheel, this series of events: continuous and mystifying, but without beginning or end. Surely, somewhere in the procession of horrors, there would be a loose end to cling to. Some loose end that would eventually unravel the pinwheel!

It was plainly not a medical affair, or at least only remotely so. The thing was in proper hands, then, with Drake following it through. And I had only to wait for his return.

He came at last, and closed the door of the room behind him. He stood over me with something of a swagger.

“Dale, I have been looking into the records of this Michael Strange,” he said quietly. “They are interesting, those records. They go back some ten years, when this fellow Strange was beginning his study of science. And now Michael Strange is one of the greatest authorities in Paris on the subject of mental telegraphy. He has gone into the study of human thought with the same thoroughness that other scientists go into the subject of radio telegraphy. He has written several books on the subject.”

Drake pulled a tiny black volume from the pocket of his coat and dropped it on the table before me. With one hand he opened it to a place which he had previously marked in pencil.

“Read it,” he said significantly.

I looked at him in wonder, and then did as he ordered. What I read was this:

“Mental telegraphy is a science, not a myth. It is a very real fact, a very real power which can be developed only by careful research. To most people it is merely a curiosity. They sit, for instance, in a crowded room at some uninteresting lecture, and stare continually at the back of some unsuspecting companion until that companion, by the power of suggestion, turns suddenly around. Or they think heavily of a certain person nearby, perhaps commanding him mentally to hum a certain popular tune, until the victim, by the power of their will, suddenly fulfills the order. To such persons, the science of mental telegraphy is merely an amusement.

“And so it will be, until science has brought it to such a perfection that these waves of thought can be broadcast--that they can be transmitted through the ether precisely as radio waves are transmitted. In other words, mental telegraphy is at present merely a mild form of hypnotism. Until it has been developed so that those hypnotic powers can be directed through space, and directed accurately to those individuals to whom they are intended, this science will have no significance. It remains for scientists of to-day to bring about that development.”

I closed the book. When I looked up, Drake was watching me intently, as if expecting me to say something.

“Drake,” I said slowly, more to myself than to him, “the pinwheel is beginning to unravel. We have found the beginning thread. Perhaps, if we follow that thread...”

Drake smiled.

“If you’ll pick up your hat and coat, Dale,” he interrupted, “I think we have an appointment. This Michael Strange, whose book you have just enjoyed so immensely, is now residing on a certain quiet little side street about three miles from the square, in London!”

I followed Drake in silence, until we had left Cheney Lane in the gloom behind us. At the entrance to the square my companion called a cab; and from there on we rode slowly, through a heavy darkness which was blanketed by a wet, penetrating fog. The cabby, evidently one who knew my companion by sight (and what London cabby does not know his Scotland Yard men!) chose a route that twisted through gloomy, uninhabited side streets, seldom winding into the main route of traffic.

As for Drake, he sank back in the uncomfortable seat and made no attempt at conversation. For the entire first part of our journey he said nothing. Not until we had reached a black, unlighted section of the city did he turn to me.

“Dale,” he said at length, “have you ever hunted tiger?”

I looked at him and laughed.

“Why?” I replied. “Do you expect this hunt of ours will be something of a blind chase?”

“It will be a blind chase, no doubt of it,” he said. “And when we have followed the trail to its end, I imagine we shall find something very like a tiger to deal with. I have looked rather deeply into Michael Strange’s life, and unearthed a bit of the man’s character. He has twice been accused of murder--murder by hypnotism--and has twice cleared himself by throwing scientific explanations at the police. That is the nature of his entire history for the past ten years.”

I nodded, without replying. As Drake turned away from me again, our cab poked its laboring nose into a narrowing, gloomy street. I had a glimpse of a single unsteady street lamp on the corner, and a dim sign, “Mate Lane.” And then we were dragging along the curb. The cab stopped with a groan.

I had stepped down and was standing by the cab door when suddenly, from the darkness in front of me, a strange figure advanced to my side. He glanced at me intently; then, seeing that I was evidently not the man he sought, he turned to Drake. I heard a whispered greeting and an undertone of conversation. Then, quietly, Drake stepped toward me.

“Dale,” he said. “I thought it best that I should not show myself here to-night. No, there is no time for explanation now; you will understand later. Perhaps”--significantly--”sooner than you anticipate. Inspector Hartnett will go through the rest of this pantomime with you.”

I shook hands with Drake’s man, still rather bewildered at the sudden substitution. Then, before I was aware of it, Drake had vanished and the cab was gone. We were alone, Hartnett and I, in Mate Lane.

The home of Michael Strange--number seven--was hardly inviting. No light was in evidence. The big house stood like a huge, unadorned vault set back from the street, some distance from its adjoining buildings. The heavy steps echoed to our footbeats as we mounted them in the darkness; and the sound of the bell, as Hartnett pressed it came sharply to us from the silence of the interior.

We stood there, waiting. In the short interval before the door opened, Hartnett glanced at his watch (it was nearly ten o’clock), and said to me:

“I imagine, Doctor, we shall meet a blank wall. Let me do the talking, please.”

That was all. In another moment the big door was pulled slowly open from the inside, and in the entrance, glaring out at us, stood the man we had come to see. It is not hard to remember that first impression of Michael Strange. He was a huge man, gaunt and haggard, moulded with the hunched shoulders and heavy arms of a gorilla. His face seemed to be unconsciously twisted into a snarl. His greeting, which came only after he had stared at us intently, for nearly a minute, was curt and rasping.

“Well, gentlemen? What is it?”

“I should like a word with Dr. Michael Strange,” said my companion quietly.

“I am Michael Strange.”

“And I,” replied Hartnett, with a suggestion of a smile, “am Raoul Hartnett, from Scotland Yard.”

I did not see any sign of emotion on Strange’s face. He stepped back in silence to allow us to enter. Then closing the big door after us, he led the way along a carpeted hall to a small, ill-lighted room just beyond. Here he motioned us to be seated, he himself standing upright beside the table, facing us.

“From Scotland Yard,” he said, and the tone was heavy with dull sarcasm. “I am at your service, Mr. Hartnett.”

And now, for the first time, I wondered just why Drake had insisted on my coming here to this gloomy house in Mate Lane. Why he had so deliberately arranged a substitute so that Michael Strange should not come face to face with him directly. Evidently Hartnett had been carefully instructed as to his course of action--but why this seemingly unnecessary caution on Drake’s part? And now, after we had gained admission, what excuse would Hartnett offer for the intrusion? Surely he would not follow the bull-headed rôle of a common policeman!

There was no anger, no attempt at dramatics, in Hartnett’s voice. He looked quietly up at our host.

“Dr. Strange,” he said at length, “I have come to you for your assistance. Last night, some time after midnight, Franklin White was strangled to death. He was murdered, according to substantial evidence, by the girl he was going to marry--Margot Vernee. I come to you because you know this girl rather well, and can perhaps help Scotland Yard in finding her motive for killing White.”

Michael Strange said nothing. He stood there, scowling down at my companion in silence. And I, too, I must admit, turned upon Hartnett with a stare of bewilderment. His accusation of Margot had brought a sense of horror to me. I had expected almost anything from him, even to a mad accusation of Strange himself. But I had hardly foreseen this cold blooded declaration.