“Not tonight,” he said.

“But why? You’re wrong!” cried Josephine.

He dropped his head and became oblivious.

“Well!” said Cyril Scott, rising at last with a bored exclamation. “I think I’ll retire.”

“Will you?” said Julia, also rising. “You’ll find your candle outside.”

She went out. Scott bade good night, and followed her. The four people remained in the room, quite silent. Then Robert rose and began to walk about, agitated.

“Don’t you go back to ’em. Have a night out. You stop here tonight,” Jim said suddenly, in a quiet intimate tone.

The stranger turned his head and looked at him, considering.

“Yes?” he said. He seemed to be smiling coldly.

“Oh, but!” cried Josephine. “Your wife and your children! Won’t they be awfully bothered? Isn’t it awfully unkind to them?”

She rose in her eagerness. He sat turning up his face to her. She could not understand his expression.

“Won’t you go home to them?” she said, hysterical.

“Not tonight,” he replied quietly, again smiling.

“You’re wrong!” she cried. “You’re wrong!” And so she hurried out of the room in tears.

“Er—what bed do you propose to put him in?” asked Robert rather officer–like.

“Don’t propose at all, my lad,” replied Jim, ironically—he did not not like Robert. Then to the stranger he said:

“You’ll be all right on the couch in my room?—it’s a good couch, big enough, plenty of rugs—” His voice was easy and intimate.

Aaron looked at him, and nodded.

They had another drink each, and at last the two set off, rather stumbling, upstairs. Aaron carried his bowler hat with him.

Robert remained pacing in the drawing–room for some time. Then he went out, to return in a little while. He extinguished the lamps and saw that the fire was safe. Then he went to fasten the window–doors securely. Outside he saw the uncanny glimmer of candles across the lawn. He had half a mind to go out and extinguish them—but he did not. So he went upstairs and the house was quiet. Faint crumbs of snow were falling outside.

When Jim woke in the morning Aaron had gone. Only on the floor were two packets of Christmas–tree candles, fallen from the stranger’s pockets. He had gone through the drawing–room door, as he had come. The housemaid said that while she was cleaning the grate in the dining–room she heard someone go into the drawing–room: a parlour– maid had even seen someone come out of Jim’s bedroom. But they had both thought it was Jim himself, for he was an unsettled house mate.

There was a thin film of snow, a lovely Christmas morning.

Our story will not yet see daylight. A few days after Christmas, Aaron sat in the open shed at the bottom of his own garden, looking out on the rainy darkness. No one knew he was there. It was some time after six in the evening.

“Do you know, Watson,” said Holmes as we sat together in the gathering darkness, “I have really some scruples as to taking you to-night. There is a distinct element of danger.”

“Can I be of assistance?”

“Your presence might be invaluable.”

“Then I shall certainly come.”

“It is very kind of you.”

“You speak of danger. You have evidently seen more in these rooms than was visible to me.”

“No, but I fancy that I may have deduced a little more. I imagine that you saw all that I did.”

“I saw nothing remarkable save the bell-rope, and what purpose that could answer I confess is more than I can imagine.”

“You saw the ventilator, too?”

“Yes, but I do not think that it is such a very unusual thing to have a small opening between two rooms. It was so small that a rat could hardly pass through.”

“I knew that we should find a ventilator before ever we came to Stoke Moran.”

“My dear Holmes!”

“Oh, yes, I did. You remember in her statement she said that her sister could smell Dr. Roylott’s cigar. Now, of course that suggested at once that there must be a communication between the two rooms. It could only be a small one, or it would have been remarked upon at the coroner’s inquiry. I deduced a ventilator.”

“But what harm can there be in that?”

“Well, there is at least a curious coincidence of dates. A ventilator is made, a cord is hung, and a lady who sleeps in the bed dies. Does not that strike you?”

“I cannot as yet see any connection.”

“Did you observe anything very peculiar about that bed?”

“No.”

“It was clamped to the floor. Did you ever see a bed fastened like that before?”

“I cannot say that I have.”

“The lady could not move her bed. It must always be in the same relative position to the ventilator and to the rope — or so we may call it, since it was clearly never meant for a bell-pull.”

“Holmes,” I cried, “I seem to see dimly what you are hinting at. We are only just in time to prevent some subtle and horrible crime.”

“Subtle enough and horrible enough. When a doctor does go wrong he is the first of criminals. He has nerve and he has knowledge. Palmer and Pritchard were among the heads of their profession. This man strikes even deeper, but I think, Watson, that we shall be able to strike deeper still. But we shall have horrors enough before the night is over; for goodness’ sake let us have a quiet pipe and turn our minds for a few hours to something more cheerful.”

* * *

About nine o’clock the light among the trees was extinguished, and all was dark in the direction of the Manor House. Two hours passed slowly away, and then, suddenly, just at the stroke of eleven, a single bright light shone out right in front of us.

“That is our signal,” said Holmes, springing to his feet; “it comes from the middle window.”