Ayscough drew the sheet over the dead man's face and signed to his companion to follow him outside, to a room where Melky Rubinstein, still gravely meditating over the events of the evening, was awaiting their reappearance.

"So that," said Ayscough, jerking his thumb in the direction of the mortuary, "that's Chen Li! You're certain?"

"Chen Li! without a doubt!" answered the house-surgeon. "I know him well!"

"The younger of the two?" suggested Ayscough.

The house-surgeon shook his head.

"I can't say as to that," he answered. "It would be difficult to tell which of two Chinese, of about the same age, was the older. But that's Chen. He and the other, Chang Li, are very much alike, but Chen was a somewhat smaller and shorter man."

"What do you know of them?" inquired Ayscough. "Can you say what's known at your hospital?"

"Very little," replied the house-surgeon. "They entered, as students there--we have several foreigners--about last Christmas--perhaps at the New Year. All that I know of them is that they were like most Easterns-- very quiet, unassuming, inoffensive fellows, very assiduous in their studies and duties, never giving any trouble, and very punctual in their attendance."

"And, you say, they haven't been seen at the hospital for some days?" continued Ayscough. "Now, can you tell me--it's important--since what precise date they've been absent?"

The house-surgeon reflected for a moment--then he suddenly drew out a small memorandum book from an inner pocket.

"Perhaps I can," he answered, turning the pages over. "Yes--both these men should have been in attendance on me--a class of my own, you know--on the 20th, at 10.35. They didn't turn up. I've never seen them since--in fact, I'm sure they've never been at the hospital since."

"The 20th?" observed Ayscough. He looked at Melky, who was paying great attention to the conversation. "Now let's see--old Mr. Multenius met his death on the afternoon of the 18th. Parslett was poisoned on the night of the 19th. Um!"

"And Parslett was picked up about half-way between the Chink's house and his own place, Mr. Ayscough--don't you forget that!" muttered Melky. "I'm not forgetting--don't you make no error!"

"You don't know anything more that you could tell us about these two?" asked the detective, nodding reassuringly at Melky and then turning to the house-surgeon. "Any little thing?--you never know what helps."

"I can't!" said the house-surgeon, who was obviously greatly surprised by what he had seen and heard. "These Easterns keep very much to themselves, you know. I can't think of anything."

"Don't know anything of their associates--friends--acquaintances?" suggested Ayscough. "I suppose they had some--amongst your students?"

"I never saw them in company with anybody--particularly--except a young Japanese who was in some of their classes," replied the house-surgeon. "I have seen them talking with him--in Gower Street."

"What's his name?" asked Ayscough, pulling out a note-book.

"Mr. Mori Yada," answered the house-surgeon promptly. "He lives in Gower Street--I don't know the precise number of the house. Yes, that's the way to spell his name. He's the only man I know who seemed to know these two."

"Have you seen him lately?" asked Ayscough.

"Oh, yes--regularly--today, in fact," said the house-surgeon.

He waited a moment in evident expectation of other questions; as the detective asked none--"I gather," he remarked, "that Chang Li has disappeared?"

"The house these two occupied is empty," replied Ayscough.

"I am going to suggest something," said the house-surgeon. "I know--from personal observation--that there is a tea-shop in Tottenham Court Road--a sort of quiet, privately-owned place--Pilmansey's--which these two used to frequent. I don't know if that's of any use to you?"

"Any detail is of use, sir," answered Ayscough, making another note. "Now, I'll tell this taxi-man to drive you back to the hospital. I shall call there tomorrow morning, and I shall want to see this young Japanese gentleman, too. I daresay you see that this is a case of murder--and there's more behind it!"

"You suspect Chang Li?" suggested the house-surgeon as they went out to the cab.

"Couldn't say that--yet," replied Ayscough, grimly. "For anything I know, Chang Li may have been murdered, too. But I've a pretty good notion what Chen Li was knifed for!"

When the house-surgeon had gone away, Ayscough turned to Melky.

"Come back to Molteno Lodge," he said. "They're searching it. Let's see if they've found anything of importance."

The house which had been as lifeless and deserted when Melky and the detective visited it earlier in the evening was full enough of energy and animation when they went back. One policeman kept guard at the front gate; another at the door of the yard; within the house itself, behind closed doors and drawn shutters and curtains, every room was lighted and the lynx-eyed men were turning the place upside down. One feature of the search struck the newcomers immediately--the patch of ground whereon Melky had found the dead man had been carefully roped off. Ayscough made a significant motion of his hand towards it.

"Good!" he said, "that shows they've found footprints. That may be useful. Let's hear what else they've found."

The man in charge of these operations was standing within the dining-room when Ayscough and Melky walked in, and he at once beckoned them into the room and closed the door.

"We've made two or three discoveries," he said, glancing at Ayscough. "To start with, there were footprints of a rather unusual sort round these bushes where the man was lying--so I've had it carefully fenced in around there--we'll have a better look at 'em, in daylight. Very small prints, you understand--more like a woman's than a man's."

Ayscough's sharp eyes turned to the hearth--there were two or three pairs of slippers lying near the fender and he pointed to them.

"These Chinamen have very small feet, I believe," he said. "The footprints are probably theirs. Well--what else?"

"This," answered the man in charge, producing a small parcel from the side-pocket of his coat, and proceeding to divest it of a temporary wrapping. "Perhaps Mr. Rubinstein will recognize it. We found it thrown away in a fire-grate in one of the bedrooms upstairs--you see, it's half burnt."

He produced a small, stoutly-made cardboard box, some three inches square, the outer surface of which was covered with a thick, glossy-surfaced dark- green paper, on which certain words were deeply impressed in gilt letters. The box was considerably charred and only fragments of the lettering on the lid remained intact--but it was not difficult to make out what the full wording had been.

. . . . enius,
  . . .nd jeweller,
    . . ed Street.

"That's one of the late Mr. Multenius's boxes," affirmed Melky at once. "Daniel Multenius, Pawnbroker and Jeweller, Praed Street--that's the full wording. Found in a fireplace, d'ye say, mister? Ah--and what had he taken out of it before he threw the box away, now, Mr. Ayscough--whoever it was that did throw it away?"

"That blessed orange and yellow diamond, I should think!" said Ayscough. "Of course! Well, anything else?"

The man in charge carefully wrapped up and put away the jeweller's box; then, with a significant glance at his fellow-detective, he slipped a couple of fingers into his waistcoat pocket and drew out what looked like a bit of crumpled paper.

"Aye!" he answered. "This! Found it--just there! Lying on the floor, at the end of this table."

He opened out the bit of crumpled paper as he spoke and held it towards the other two. Ayscough stared, almost incredulously, and Melky let out a sharp exclamation.

"S'elp us!" he said. "A five-hundred-pound bank-note!"

"That's about it," remarked the exhibitor. "Bank of England note for five hundred of the best! And--a good 'un, too. Lying on the floor."

"Take care of it," said Ayscough laconically. "Well--you haven't found any papers, documents, or anything of that sort, that give any clue?"

"There's a lot of stuff there," answered the man in charge, pointing to a pile of books and papers on the table, "but it seems to be chiefly exercises and that sort of thing. I'll look through it myself, later."

"See if you can find any letters, addresses, and so on," counselled Ayscough. He turned over some of the books, all of them medical works and text-books, opening some of them at random. And suddenly he caught sight of the name which the house-surgeon had given him half-an-hour before, written on a fly-leaf: Mori Yada, 491, Gower Street--and an idea came into his mind. He bade the man in charge keep his eyes open and leave nothing unexamined, and tapping Melky's arm, led him outside. "Look here!" he said, drawing out his watch, as they crossed the hall, "it's scarcely ten o'clock, and I've got the address of that young Jap. Come on--we'll go and ask him a question or two."

So for the second time that evening, Melky, who was beginning to feel as if he were on a chase which pursued anything but a straight course, found himself in Gower Street again, and followed Ayscough along, wondering what was going to happen next, until the detective paused at the door of a tall house in the middle of the long thoroughfare and rang the bell. A smart maid answered that ring and looked dubiously at Ayscough as he proffered a request to see Mr. Mori Yada. Yes--Mr. Yada was at home, but he didn't like to see any one, of an evening when he was at his studies, and--in fact he'd given orders not to be disturbed at that time.

"I think he'll see me, all the same," said Ayscough, drawing out one of his professional cards. "Just give him that, will you, and tell him my business is very important."

He turned to Melky when the girl, still looking unwilling, had gone away upstairs, and gave him a nudge of the elbow.

"When we get up there--as we shall," whispered Ayscough, "you watch this Jap chap while I talk to him. Study his face--and see if anything surprises him."

"Biggest order, mister--with a Jap!" muttered Melky. "Might as well tell me to watch a stone image--their faces is like wood!"

"Try it!" said Ayscough. "Flicker of an eyelid--twist of the lip-- anything! Here's the girl back again."

A moment later Melky, treading close on the detective's heels, found himself ushered into a brilliantly-lighted, rather over-heated room, somewhat luxuriously furnished, wherein, in the easiest of chairs, a cigar in his lips, a yellow-backed novel in his hand, sat a slimly-built, elegant young gentleman whose face was melting to a smile.