There was nothing about the house to distinguish it from its stolid and respectable neighbors. It had a dingy face, woodwork painted a dark red with the traditional brass knocker and bell-pull. The windows were hung with curtains of the ordinary type, the Venetian blinds were half down, which in itself is a sign of middle-class respectability. In the center of the red door was a small brass plate bearing the name of Dr. Sergius Tchigorsky.

Not that Dr. Tchigorsky was a medical practitioner in the ordinary sense of the word. No neatly appointed "pillbox" ever stood before 101; no patient ever passed the threshold.

Tchigorsky was a savant and a traveler to boot; a man who dealt in strange out-of-the-way things, and the interior of his house would have been a revelation to the top-hatted, frock-coated doctors and lawyers and City men who elected to make their home in Brant Street, W.

The house was crammed with curiosities and souvenirs of travel from basement to garret. A large sky-lighted billiard-room at the back of the house had been turned into a library and laboratory combined.

And here, when not traveling, Tchigorsky spent all his time, seeing strange visitors from time to time, Mongolians, Hindoos, natives of Tibet—for Tchigorsky was one of the three men who had penetrated to the holy city of Lassa, and returned to tell the tale.

The doctor came into his study from his breakfast, and stood ruminating, rubbing his hands before the fire. In ordinary circumstances he would have been a fine man of over six feet in height.

But a cruel misfortune had curved his spine, while his left leg dragged almost helplessly behind him, his hands were drawn up as if the muscles had been cut and then knotted up again.

Tchigorsky had entered Lassa five years ago as a god who walks upright. When he reached the frontier six months later he was the wreck he still remained. And of those privations and sufferings Tchigorsky said nothing. But there were times when his eyes gleamed and his breath came short and he pined for the vengeance yet to be his.

As to his face, it was singularly strong and intellectual. Yet it was disfigured with deep seams checkered like a chessboard. We have seen something like it before, for the marks were identical with those that disfigured Ralph Ravenspur and made his face a horror to look upon.

A young man rose from the table where he was making some kind of an experiment. He was a fresh-colored Englishman, George Abell by name, and he esteemed it a privilege to call himself Tchigorsky's secretary.

"Always early and always busy," Tchigorsky said. "Is there anything in the morning papers that is likely to interest me, Abell?"

"I fancy so," Abell replied thoughtfully. "You are interested in the Ravenspur case?"

A lurid light leapt into the Russian's eyes. He seemed to be strangely moved. He paced up and down the room, dragging his maimed limb after him.

"Never more interested in anything in my life," he said. "You know as much of my past as any man, but there are matters, experiences unspeakable. My face, my ruined frame! Whence come these cruel misfortunes? That secret will go down with me to the grave. Of that I could speak to one man alone, and I know not whether that man is alive or dead."

Tchigorsky's words trailed off into a rambling incoherent murmur. He was far away with his own gloomy and painful thoughts. Then he came back to earth with a start. He stood with his back to the fireplace, contemplating Abell.

"I am deeply interested in the Ravenspur case, as you know," he said. "A malignant fiend is at work yonder—a fiend with knowledge absolutely supernatural. You smile! I myself have seen the powers of darkness doing the bidding of mortal man. All the detectives in Europe will never lay hands upon the destroyer of the Ravenspurs. And yet, in certain circumstances, I could."

"Then, in that case, sir, why don't you?"

"Do it? I said in certain circumstances. I have part of a devilish puzzle; the other part is in the hands of a man who may be dead. I hold half of the bank-note; somebody else has the other moiety. Until we can come together, we are both paupers. If I can find that other man, and he has the nerve and the pluck he used to possess, the curse of the Ravenspurs will cease. But, then, I shall never see my friend again."

"But you might solve the problem alone."

"Impossible. That man and myself made a most hazardous expedition in search of dreadful knowledge. That formula we found. For the purposes of safety, we divided it. And then we were discovered. Of what followed I dare not speak. I dare not even think.

"I escaped from my dire peril, but I cannot hope that my comrade was so fortunate. He must be dead. And, without him, I am as powerless as if I knew nothing. I have no proof. Yet I know quite well who is responsible for those murders at Ravenspur."

Abell stared at his chief in astonishment. He knew Tchigorsky too well to doubt the evidence of his simple word. The Russian was too strong a man to boast.

"You cannot understand," he said. "It is impossible to understand without the inner knowledge that I possess, and even my knowledge is not perfect. Were I to tell the part I know I should be hailed from one end of England to the other as a madman. I should be imprisoned for malignant slander. But if the other man turned up—if only the other man should turn up!"

Tchigorsky broke into a rambling reverie again. When he emerged to mundane matters once more he ordered Abell to read the paragraph relating to the latest phase of the tragedy of the lost Ravenspur.

"It runs," said Abell, "'Another Strange Affair at Ravenspur Castle. The mystery of this remarkable case still thickens. Late on Wednesday night Mr. Rupert Ravenspur, the head of the family, was awakened by a choking sensation and a total loss of breath. On attempting to leave his bed, the unfortunate gentleman found himself unable to move.

"'He states that the room appeared to be filled with a fine spray of some sickly, sweet drug or liquid that seemed to act upon him as chloroform does on a subject with a weak heart. Mr. Ravenspur managed to cry out, but the vapor held him down, and was slowly stifling him——'"

"Ah," Tchigorsky cried. "Ah, I thought so. Go on!"

His eyes were gleaming; his whole face glistened with excitement.

"'Providentially the cry reached the ears of another of the Ravenspurs. This gentleman burst open his father's door, and noticing the peculiar, pungent odor, had the good sense to break a window and admit air into the room.

"'This prompt action was the means of saving the life of the victim, and it is all the more remarkable because it was carried out by a Mr. Ralph Ravenspur, a blind gentleman, who had just returned from foreign parts.'"

A cry—a scream broke from Tchigorsky's lips. He danced about the room like a madman. For the time being it was impossible for the astonished secretary to determine whether this was joy or anguish.

"You are upset about something, sir," he said.

Tchigorsky recovered himself by a violent effort that left him trembling like a reed swept in the wind. He gasped for breath.

"It was the madness of an overwhelming joy!" he cried. "I would cheerfully have given ten years of my life for this information. Abell, you will have to go to Ravenspur for me to-day."

Abell said nothing. He was used to these swift surprises.

"You are to see this Ralph Ravenspur, Abell," continued Tchigorsky. "You are not to call at the castle; you are to hang about till you get a chance of delivering my message unseen. The mere fact that Ralph Ravenspur is blind will suffice for a clue to his identity. Look up the time-table!"

Abell did so. He found a train to land him at Biston Junction, some ten miles from his destination. Half an hour later he was ready to start. From an iron safe Tchigorsky took a small object and laid it in Abell's hand.

"Give him that," he said. "You are simply to say: 'Tchigorsky—Danger,' and come away, unless Ralph Ravenspur desires speech with you. Now, go. And as you value your life, do not lose that casket."

It was a small brass box no larger than a cigarette case, rusty and tarnished, and covered with strange characters, evidently culled from some long-forgotten tongue.