“Very good. Mrs. Marker, you can go. Now we are making a little progress. Our lady enters the room, advances to the bureau, and either opens it or tries to do so. While she is thus engaged, young Willoughby Smith enters the room. In her hurry to withdraw the key, she makes this scratch upon the door. He seizes her, and she, snatching up the nearest object, which happens to be this knife, strikes at him in order to make him let go his hold. The blow is a fatal one. He falls and she escapes, either with or without the object for which she has come. Is Susan, the maid, there? Could anyone have got away through that door after the time that you heard the cry, Susan?”

“No, sir, it is impossible. Before I got down the stair, I’d have seen anyone in the passage. Besides, the door never opened, or I would have heard it.”

“That settles this exit. Then no doubt the lady went out the way she came. I understand that this other passage leads only to the professor’s room. There is no exit that way?”

“No, sir.”

“We shall go down it and make the acquaintance of the professor. Halloa, Hopkins! this is very important, very important indeed. The professor’s corridor is also lined with cocoanut matting.”

“Well, sir, what of that?”

“Don’t you see any bearing upon the case? Well, well. I don’t insist upon it. No doubt I am wrong. And yet it seems to me to be suggestive. Come with me and introduce me.”

We passed down the passage, which was of the same length as that which led to the garden. At the end was a short flight of steps ending in a door. Our guide knocked, and then ushered us into the professor’s bedroom.

It was a very large chamber, lined with innumerable volumes, which had overflowed from the shelves and lay in piles in the corners, or were stacked all round at the base of the cases. The bed was in the centre of the room, and in it, propped up with pillows, was the owner of the house. I have seldom seen a more remarkable-looking person. It was a gaunt, aquiline face which was turned towards us, with piercing dark eyes, which lurked in deep hollows under overhung and tufted brows. His hair and beard were white, save that the latter was curiously stained with yellow around his mouth. A cigarette glowed amid the tangle of white hair, and the air of the room was fetid with stale tobacco smoke. As he held out his hand to Holmes, I perceived that it was also stained with yellow nicotine.

“A smoker, Mr. Holmes?” said he, speaking in well-chosen English, with a curious little mincing accent. “Pray take a cigarette. And you, sir? I can recommend them, for I have them especially prepared by Ionides, of Alexandria. He sends me a thousand at a time, and I grieve to say that I have to arrange for a fresh supply every fortnight. Bad, sir, very bad, but an old man has few pleasures. Tobacco and my work - that is all that is left to me.”

Holmes had lit a cigarette and was shooting little darting glances all over the room.

“Tobacco and my work, but now only tobacco,” the old man exclaimed. “Alas! what a fatal interruption! Who could have foreseen such a terrible catastrophe? So estimable a young man! I assure you that, after a few months’ training, he was an admirable assistant. What do you think of the matter, Mr. Holmes?”

“I have not yet made up my mind.”

“I shall indeed be indebted to you if you can throw a light where all is so dark to us. To a poor bookworm and invalid like myself such a blow is paralyzing. I seem to have lost the faculty of thought. But you are a man of action - you are a man of affairs. It is part of the everyday routine of your life. You can preserve your balance in every emergency. We are fortunate, indeed, in having you at our side.”