"What do you mean?" asked Dr. van Heerden.

"I merely repeat the words of the dead man," answered Beale, "heart failure!"

He picked up from the table the leather case which the doctor had taken from his pocket. There were four little phials and one of these was uncorked.

"Digitalis!" he read. "That shouldn't kill him, doctor."

He looked at van Heerden thoughtfully, then picked up the phial again. It bore the label of a well-known firm of wholesale chemists, and the seal had apparently been broken for the first time when van Heerden opened the tiny bottle.

"You have sent for the police?" Beale asked the agitated manager.

"Oui, m'sieur—directly. They come now, I think."

He walked to the vestibule to meet three men in plain clothes who had just come through the swing-doors. There was something about van Heerden's attitude which struck Beale as strange. He was standing in the exact spot he had stood when the detective had addressed him. It seemed as if something rooted him to the spot. He did not move even when the ambulance men were lifting the body nor when the police were taking particulars of the circumstances of the death. And Beale, escorting the shaken girl up the broad staircase to a room where she could rest and recover, looked back over his shoulder and saw him still standing, his head bent, his fingers smoothing his beard.

"It was dreadful, dreadful," said the girl with a shiver. "I have never seen anybody—die. It was awful."

Beale nodded. His thoughts were set on the doctor. Why had he stood so motionless? He was not the kind of man to be shocked by so normal a phenomenon as death. He was a doctor and such sights were common to him. What was the reason for this strange paralysis which kept him chained to the spot even after the body had been removed?

The girl was talking, but he did not hear her. He knew instinctively that in van Heerden's curious attitude was a solution of PrÉdeaux's death.

"Excuse me a moment," he said.

He passed with rapid strides from the room, down the broad stairway and into the palm-court.

Van Heerden had gone.

The explanation flashed upon him and he hurried to the spot where the doctor had stood.

On the tessellated floor was a little patch no bigger than a saucer which had been recently washed.

He beckoned the manager.

"Who has been cleaning this tile?" he asked.

The manager shrugged his shoulders.

"It was the doctor, sare—so eccentric! He call for a glass of water and he dip his handkerchief in and then lift up his foot and with rapidity incredible he wash the floor with his handkerchief!"

"Fool!" snapped Beale. "Oh, hopeless fool!"

"Sare!" said the startled manager.

"It's all right, M'sieur Barri," smiled Beale ruefully. "I was addressing myself—oh, what a fool I've been!"

He went down on his knees and examined the floor.

"I want this tile, don't let anybody touch it," he said.

Of course, van Heerden had stood because under his foot he had crushed the digitalis tablet he had taken from the phial, and for which he had substituted something more deadly. Had he moved, the powdered tablet would have been seen. It was simple—horribly simple.

He walked slowly back to where he had left Oliva.

What followed seemed ever after like a bad dream to the girl. She was stunned by the tragedy which had happened under her eyes and could offer no evidence which in any way assisted the police in their subsequent investigation, the sum of which was ably set forth in the columns of the Post Record.

"The tragedy which occurred in the Palm-Court of the Grand Alliance Hotel yesterday must be added to the already long list of London's unravelled mysteries. The deceased, a man named Jackson, has been staying at the hotel for a week and was on the point of departure for Canada. At the last moment Dr. van Heerden, who was assisting the unfortunate man, discovered that Jackson was no other than the wanted man in the Millinborn murder, a crime which most of our readers will recall.

"Dr. van Heerden stated to our representative that the man had represented that he was a friend of the late John Millinborn, but was anxious to get to Canada. He had produced excellent credentials, and Dr. van Heerden, in a spirit of generosity, offered to assist him. At the eleventh hour, however, he was struck with the likeness the man bore to the published description of the missing man in the Millinborn case, and was on the point of telegraphing to the authorities at Liverpool, when he discovered that Jackson had missed the train.

"The present tragedy points to suicide. The man, it will be remembered, collapsed, and Dr. van Heerden rendered first aid, administering to the man a perfectly harmless drug. The post-mortem examination reveals the presence in the body of a considerable quantity of cyanide of potassium, and the police theory is that this was self-administered before the collapse. In the man's pocket was discovered a number of cyanide tablets.

"'I am satisfied,' said Dr. van Heerden, 'that the man already contemplated the deed, and when I voiced my suspicions in the palm-court he decided upon the action. The presence in his pocket of cyanide—one of the deadliest and quickest of poisons—suggests that he had the project in his mind. I did not see his action or, of course, I should have stopped him!'"

Oliva Cresswell read this account in her room two nights following the tragedy and was struck by certain curious inaccuracies, if all that the doctor had told her was true.

Mr. Beale read the account, smiled across the table grimly to the bearded superintendent of the Criminal Investigation Department.

"How does that strike you for ingenuity?" he said, pushing the paper over the table.

"I have read it," said the other laconically, "I think we have sufficient evidence to arrest van Heerden. The tile from the Grand Alliance shows traces of digitalis."

Beale shook his head.

"The case would fall," he said. "What evidence have you? We did not confiscate his medicine-case. He might have dropped a tablet of digitalis by accident. The only evidence you could convict van Heerden on is proof that he brought with him cyanide tablets which he slipped into PrÉdeaux's pocket. No, we can prove nothing."

"What is your theory in connection with the crime?"

"I have many theories," said Mr. Beale, rising and pacing the room, "and one certainty. I am satisfied that Millinborn was killed by Doctor van Heerden. He was killed because, during the absence of Mr. Kitson in the village, the doctor forced from the dying man a secret which up till then he had jealously preserved. When Kitson returned he found his friend, as he thought, in extremis, and van Heerden also thought that John Millinborn would not speak again. To his surprise Millinborn did speak and van Heerden, fearful of having his villainy exposed, stabbed him to the heart under the pretext of assisting him to lie down.

"Something different occurred at the Grand Alliance Hotel. A man swoons, immediately he is picked up by the doctor, who gives him a harmless drug—that is to say, harmless in small quantities. In five seconds the man is dead. At the inquest we find he has been poisoned—cyanide is found in his pocket. And who is this man? Obviously the identical person who witnessed the murder of John Millinborn and whom we have been trying to find ever since that crime."

"Van Heerden won't escape the third time. His presence will be a little more than a coincidence," said the superintendent.

Beale laughed.

"There will be no third time," he said shortly, "van Heerden is not a fool."

"Have you any idea what the secret was that he wanted to get from old Millinborn?" asked the detective.

Beale nodded.

"Yes, I know pretty well," he said, "and in course of time you will know, too."

The detective was glancing over the newspaper account.

"I see the jury returned a verdict of 'Suicide whilst of unsound mind!'" he said. "This case ought to injure van Heerden, anyway."

"That is where you are wrong," said Beale, stopping in his stride, "van Heerden has so manoeuvred the Pressmen that he comes out with an enhanced reputation. You will probably find articles in the weekly papers written and signed by him, giving his views on the indiscriminate sale of poisons. He will move in a glamour of romance, and his consulting-rooms will be thronged by new admirers."

"It's a rum case," said the superintendent, rising, "and if you don't mind my saying so, Mr. Beale, you're one of the rummiest men that figure in it. I can't quite make you out. You are not a policeman and yet we have orders from the Foreign Office to give you every assistance. What's the game?"

"The biggest game in the world," said Beale promptly, "a game which, if it succeeds, will bring misery and suffering to thousands, and will bring great businesses tumbling, and set you and your children and your children's children working for hundreds of years to pay off a new national debt."

"Man alive!" said the other, "are you serious?"

Beale nodded.

"I was never more serious in my life," he said, "that is why I don't want the police to be too inquisitive in regard to this murder of Jackson, whose real name, as I say, is PrÉdeaux. I can tell you this, chief, that you are seeing the development of the most damnable plot that has ever been hatched in the brain of the worst miscreant that history knows. Sit down again. Do you know what happened last year?" he asked.

"Last year?" said the superintendent. "Why, the war ended last year."

"The war ended, Germany was beaten, and had to accept terms humiliating for a proud nation, but fortunately for her Prussia was not proud, she was merely arrogant. Her worst blow was the impoverishing conditions which the Entente Powers imposed. That is to say, they demanded certain concessions of territory and money which, added to the enormous interest of war stock which the Germans had to pay, promised to cripple Prussia for a hundred years."

"Well?" said the detective, when the other had stopped.

"Well?" repeated Beale, with a hard little smile. "Germany is going to get that money back."

"War?"

Beale laughed.

"No, nothing so foolish as war. Germany has had all the war she wants. Oh no, there'll be no war. Do you imagine that we should go to war because I came to the Foreign Office with a crazy story. I can tell you this, that officially the German Government have no knowledge of this plot and are quite willing to repudiate those people who are engaged in it. Indeed, if the truth be told, the Government has not contributed a single mark to bring the scheme to fruition, but when it is working all the money required will be instantly found. At present the inventor of this delightful little scheme finds himself with insufficient capital to go ahead. It is his intention to secure that capital. There are many ways by which this can be done. He has already borrowed £40,000 from White, of Punsonby's."

Superintendent McNorton whistled.

"There are other ways," Beale went on, "and he is at liberty to try them all except one. The day he secures control of that fortune, that day I shoot him."

"The deuce you will?" said the startled Mr. McNorton.

"The deuce I will," repeated Beale.

There was a tap at the door and McNorton rose.

"Don't go," said Beale, "I would like to introduce you to this gentleman."

He opened the door and a grey-haired man with a lean, ascetic face came in.

Beale closed the door behind him and led the way to the dining-room.

"Mr. Kitson, I should like you to know Superintendent McNorton."

The two men shook hands.

"Well?" said Kitson, "our medical friend seems to have got away with it." He sat at the table, nervously drumming with his fingers. "Does the superintendent know everything?"

"Nearly everything," replied Beale.

"Nearly everything," repeated the superintendent with a smile, "except this great Green Rust business. There I admit I am puzzled."

"Even I know nothing about that," said Kitson, looking curiously at Beale. "I suppose one of these days you will tell us all about it. It is a discovery Mr. Beale happed upon whilst he was engaged in protecting Miss——" He looked at Beale and Beale nodded—"Miss Cresswell," said Kitson.

"The lady who was present at the murder of Jackson?"

"There is no reason why we should not take you into our confidence, the more so since the necessity for secrecy is rapidly passing. Miss Oliva Cresswell is the niece of John Millinborn. Her mother married a scamp who called himself Cresswell but whose real name was PrÉdeaux. He first spent every penny she had and then left her and her infant child."

"PrÉdeaux!" cried the detective. "Why you told me that was Jackson's real name."

"Jackson, or PrÉdeaux, was her father," said Kitson, "it was believed that he was dead; but after John Millinborn's death I set inquiries on foot and discovered that he had been serving a life sentence in Cayenne and had been released when the French President proclaimed a general amnesty at the close of the war. He was evidently on his way to see John Millinborn the day my unhappy friend was murdered, and it was the recognition of his daughter in the palm-court of the Grand Alliance which produced a fainting-fit to which he was subject."

"But how could he recognize the daughter? Had he seen her before?"

For answer Kitson took from his pocket a leather folder and opened it. There were two photographs. One of a beautiful woman in the fashion of 25 years before; and one a snapshot of a girl in a modern costume, whom McNorton had no difficulty in recognizing as Oliva Cresswell.

"Yes," he said, "they might be the same person."

"That's the mother on the left," explained Kitson, "the resemblance is remarkable. When Jackson saw the girl he called her Mary—that was his wife's name. Millinborn left the whole of his fortune to Miss Cresswell, but he placed upon me a solemn charge that she was not to benefit or to know of her inheritance until she was married. He had a horror of fortune-hunters. This was the secret which van Heerden surprised—I fear with violence—from poor John as he lay dying. Since then he has been plotting to marry the girl. To do him justice, I believe that the cold-blooded hound has no other wish than to secure her money. His acquaintance with White, who is on the verge of ruin, enabled him to get to know the girl. He persuaded her to come here and a flat was found for her. Partly," said the lawyer dryly, "because this block of flats happens to be her own property and the lady who is supposed to be the landlady is a nominee of mine."

"And I suppose that explains Mr. Beale," smiled the inspector.

"That explains Mr. Beale," said Kitson, "whom I brought from New York especially to shadow van Heerden and to protect the girl. In the course of investigations Mr. Beale has made another discovery, the particulars of which I do not know."

There was a little pause.

"Why not tell the girl?" said the superintendent.

Kitson shook his head.

"I have thought it out, and to tell the girl would be tantamount to breaking my faith with John Millinborn. No, I must simply shepherd her. The first step we must take"—he turned to Beale—"is to get her away from this place. Can't you shift your offices to—say New York?"

Beale shook his head.

"I can and I can't," he said. "If you will forgive my saying so, the matter of the Green Rust is of infinitely greater importance than Miss Cresswell's safety."

James Kitson frowned.

"I don't like to hear you say that, Beale."

"I don't like hearing myself say it," confessed the other, "but let me put it this way. I believe by staying here I can afford her greater protection and at the same time put a spoke in the wheel of Mr. van Heerden's larger scheme."

Kitson pinched his lips thoughtfully.

"Perhaps you are right," he said. "Now I want to see this young lady, that is why I have come. I suppose there will be no difficulty?"

"None at all, I think," said Beale. "I will tell her that you are interested in the work she is doing. I might introduce you as Mr. Scobbs," he smiled.

"Who is Scobbs?"

"He is a proprietor of a series of hotels in Western Canada, and is, I should imagine, a most praiseworthy and inoffensive captain of minor industry, but Miss Cresswell is rather interested in him," he laughed. "She found the name occurring in Canadian guide-books and was struck by its quaintness."

"Scobbs," said the lawyer slowly. "I seem to know that name."

"You had better know it if I am going to introduce you as Scobbs himself," laughed Beale.

"Shall I be in the way?" asked the superintendent.

"No, please stay," said Beale. "I would like you to see this lady. We may want your official assistance one of these days to get her out of a scrape."

Mr. Beale passed out of the flat and pressed the bell of the door next to his. There was no response. He pressed it again after an interval, and stepped back to look at the fanlight. No light showed and he took out his watch. It was nine o'clock. He had not seen the girl all day, having been present at the inquest, but he had heard her door close two hours before. No reply came to his second ring, and he went back to his flat.

"She's out," he said. "I don't quite understand it. I particularly requested her yesterday not to go out after dark for a day or two."

He walked into his bedroom and opened the window. The light of day was still in the sky, but he took a small electric lamp to guide him along the narrow steel balcony which connected all the flats with the fire-escape. He found her window closed and bolted, but with the skill of a professional burglar he unfastened the catch and stepped inside.

The room was in darkness. He switched on the light and glanced round. It was Oliva's bedroom, and her workday hat and coat were lying on the bed. He opened the long cupboard where she kept her limited wardrobe. He knew, because it was his business to know, every dress she possessed. They were all there as, also, were the three hats which she kept on a shelf. All the drawers of the bureau were closed and there was no sign of any disorder such as might be expected if she had changed and gone out. He opened the door of the bedroom and walked into the sitting-room, lighting his way across to the electric switch by means of his lamp.

The moment the light flooded the room he realized that something was wrong. There was no disorder, but the room conveyed in some indescribable manner a suggestion of violence. An object on the floor attracted his attention and he stooped and picked it up. It was a shoe, and the strap which had held it in place was broken. He looked at it, slipped it in his pocket and passed rapidly through the other rooms to the little kitchen and the tiny bath-room, put on the light in the hall and made a careful scrutiny of the walls and the floor.

The mat was twisted out of its place, and on the left side of the wall there were two long scratches. There was a faint sickly odour.

"Ether," he noted mentally.

He went quickly into the dining-room. The little bureau-desk was open and a letter half-finished was lying on the pad, and it was addressed to him and ran:

"Dear Mr. Beale,—

Circumstances beyond my control make it necessary for me to leave to-night for Liverpool."

That was all. It was obviously half finished. He picked it up, folded it carefully and slipped it in his pocket. Then he returned to the hall, opened the door and passed out.

He explained briefly what had happened and crossed to the doctor's flat, and rang the bell.