"You think there will be a next time?" I interrupted.

Poirot's face grew very grave.

"It is a duel to the death, won ami. You and I on the one side, the Big Four on the other. They have won the first trick; but they have failed in their plan to get me out of the way, and in the future they have to reckon with Hercule Poirot!"

For a day or two after our visit from the fake Asylum attendant I was in some hopes that he might return, and I refused to leave the flat even for a moment. As far as I could see, he had no reason to suspect that we had penetrated his disguise. He might, I thought, return and try to remove the body, but Poirot scoffed at my reasoning.

"Afon ami," he said, "if you wish you may wait in to put salt on the little bird's tail, but for me I do not waste my time so."

"Well then, Poirot," I argued, "why did he run the risk of coming at all. If he intended to return later for the body, I can see some point in his visit. He would at least be removing the evidence against himself; as it is, he does not seem to have gained anything."

Poirot shrugged his most Gallic shrug. "But you do not see with the eyes of Number Four, Hastings," he said. "You talk of evidence, but what evidence have we against him? True, we have a body, but we have no proof even that the man was murdered-prussic acid, when inhaled, leaves no trace. Again, we can find no one who saw any one enter the flat during our absence, and we have found out nothing about the movements of our late friend, Mayerling…

"No, Hastings, Number Four has left no trace, and he knows it. His visit we may call a reconnaisance. Perhaps he wanted to make quite sure that Mayerling was dead, but more likely, I think, he came to see Hercule Poirot, and to have speech with the adversary whom alone he must fear."

Poirot's reasoning appeared to me typically egotistical, but I forbore to argue.

"And what about the inquest?" I asked. "I suppose you will explain things clearly there, and let the police have a full description of Number Four."

"And to what end? Can we produce anything to impress a coroner's jury of your solid Britishers? Is our description of Number Four of any value? No; we shall allow them to call it 'Accidental Death,' and may be, although I have not much hope, our clever murderer will pat himself on the back that he deceived Hercule Poirot in the first round."

Poirot was right as usual. We saw no more of the man from the asylum, and the inquest, at which I gave evidence, but which Poirot did not even attend, aroused no public interest.

As, in view of his intended trip to South America, Poirot had wound up his affairs before my arrival, he had at this time no cases on hand, but although he spent most of his time in the flat I could get little out of him.

He remained buried in an arm-chair, and discouraged my attempts at conversation.

And then one morning, about a week after the murTHE BIG FOUR ^\ der, he asked me if I would care to accompany him of* a visit he wished to make. I was pleased, for I felt h^ was making a mistake in trying to work things out so en' tirely on his own, and I wished to discuss the case will* him. But I found he was not communicative. Even when I asked where we were going, he would not answer.

Poirot loves being mysterious. He will never part with a piece of information until the last possible moment. Ii» this instance, having taken successively a 'bus and twy trains, and arrived in the neighbourhood of one of Loa" don's most depressing southern suburbs, he consented at last to explain matters.

"We go, Hastings, to see the one man in England who knows most of the underground life of China."

"Indeed! Who is he?"

"A man you have never heard of-a Mr. John Ingles.

To all intents and purposes, he is a retired Civil Servant of mediocre intellect, with a house full of Chinese curios with which he bores his friends and acquaintances.

Nevertheless, I am assured by those who should know that the only man capable of giving me the information I seek is this same John Ingles."

A few moments more saw us ascending the steps of The Laurels, as Mr. Ingles's residence was called. Personally, I did not notice a laurel bush of any kind, so deduced that it had been named according to the usual obscure nomenclature of the suburbs.

We were admitted by an impassive-faced Chinese servant and ushered into the presence of his master. Mr.

Ingles was a squarely-built man, somewhat yellow of countenance, with deep-set eyes that were oddly reflective in character. He rose to greet us, setting aside an open letter which he had held in his hand. He referred to it after his greeting.

"Sit down, won't you? Halsey tells me that you want some information and that I may be useful to you in the matter."

"That is so, monsieur. I ask of you if you have any knowledge of a man named Li Chang Yen?"

"That's rum-very rum indeed. How did you come to hear about the man?"

"You know him, then?"

"I've met him once. And I know something of him-not quite as much as I should like to. But it surprises me that any one else in England should even have heard of him. He's a great man in his way-mandarin class and all that, you know-but that's not the crux of the matter.

There's good reason to suppose that he's the man behind it all."

"Behind what?"

"Everything. The world-wide unrest, the labour troubles that beset every nation, and the revolutions that break out in some. There are people, not scaremongers, who know what they are talking about, and they say that there is a force behind the scenes which aims at nothing less then the disintegration of civilisation.

In Russia, you know, there were many signs that Lenin and Trotsky were mere puppets whose every action was dictated by another's brain. I have no definite proof that would count with you, but I am quite convinced that this brain was Li Chang Yen's."

"Oh, come," I protested, "isn't that a bit farfetched?

How would a Chinaman cut any ice in

Russia?"

Poirot frowned at me irritably.

"For you, Hastings," he said, "everything is farfetched that comes not from your own imagination; for me, I agree with this gentleman. But continue, I pray, monsieur."

"What exactly he hopes to get out of it all I cannot pretend to say for certain," went on Mr. Ingles; "but I assume his disease is one that has attacked great brains from the time of Akbar and Alexander to Napoleon-a lust for power and personal supremacy. Up to modern times armed force was necessary for conquest, but in this century of unrest a man like Li Chang Yen can use other means. I have evidence that he has unlimited money behind him for bribery and propaganda, and there are signs that he controls some scientific force more powerful than the world has dreamed of."

Poirot was following Mr. Ingles's words with the closest attention.

"And in China?" he asked. "He moves there too?"

The other nodded in emphatic assent.

"There," he said, "although I can produce no proof that would count in a court of law, I speak from my own knowledge. I know personally every man who counts for anything in China to-day, and this I can tell you: the men who loom most largely in the public eye are men of little or no personality. They are marionettes who dance to the wires pulled by a master hand, and that hand is Li Chang Yen's. His is the controlling brain of the East to-day. We don't understand the East-we never shall; but Li Chang Yen is its moving spirit. Not that he comes out into the limelight-oh, not at all; he never moves from his palace in Pekin. But he pulls strings-that's it, pulls strings-and things happen far away."

"And is there no one to oppose him?" asked Poirot.