“Ver’ well,” he replied drowsily.  “Sorry t’ give you all this trouble.  L’ keep awake.  But I think you’re mistak’n—­”

“He says it’s very important that you shouldn’t go to sleep, and that I am to see that you don’t.  Do you understand?”

“Yes, I un’stan’.  But why does this gennlem’n—?”

“Now it’s of no use for you to ask a lot of questions,” Mrs. Schallibaum said playfully; “we’ll talk to you to-morrow.  Good night, doctor.  I’ll light you down the stairs, but I won’t come down with you, or the patient will be falling asleep again.”

Taking this definite dismissal, I retired, followed by a dreamily surprised glance from the sick man.  The housekeeper held the candle over the balusters until I reached the bottom of the stairs, when I perceived through the open door along the passage a glimmer of light from the carriage lamps.  The coachman was standing just outside, faintly illuminated by the very dim lamplight, and as I stepped into the carriage he remarked in his Scotch dialect that I “seemed to have been makin’ a nicht of it.”  He did not wait for any reply—­none being in fact needed—­but shut the door and locked it.

I lit my little pocket-lamp and hung it on the back cushion.  I even drew the board and notebook from my pocket.  But it seemed rather unnecessary to take a fresh set of notes, and, to tell the truth, I rather shirked the labour, tired as I was after my late exertions; besides, I wanted to think over the events of the evening, while they were fresh in my memory.  Accordingly I put away the notebook, filled and lighted my pipe, and settled myself to review the incidents attending my second visit to this rather uncanny house.

Considered in leisurely retrospect, that visit offered quite a number of problems that called for elucidation.  There was the patient’s condition, for instance.  Any doubt as to the cause of his symptoms was set at rest by the effect of the antidotes.  Mr. Graves was certainly under the influence of morphine, and the only doubtful question was how he had become so.  That he had taken the poison himself was incredible.  No morphinomaniac would take such a knock-down dose.  It was practically certain that the poison had been administered by someone else, and, on Mr. Weiss’s own showing, there was no one but himself and the housekeeper who could have administered it.  And to this conclusion all the other very queer circumstances pointed.

What were these circumstances?  They were, as I have said, numerous, though many of them seemed trivial.  To begin with, Mr. Weiss’s habit of appearing some time after my arrival and disappearing some time before my departure was decidedly odd.  But still more odd was his sudden departure this evening on what looked like a mere pretext.  That departure coincided in time with the sick man’s recovery of the power of speech.  Could it be that Mr. Weiss was afraid that the half-conscious man might say something compromising to him in my presence?  It looked rather like it.  And yet he had gone away and left me with the patient and the housekeeper.