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. G.o.d 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 amus.e.m.e.nt.

"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 s.p.a.ce, 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 antic.i.p.ate. 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 subst.i.tution. 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.