“How do you find him now?” Mr. Weiss asked anxiously.

“I am glad to say that there is a distinct improvement,” I replied.  “But we must persevere.  He is by no means out of the wood yet.”

I examined the coffee, which looked black and strong and had a very reassuring smell, and, pouring out half a cupful, approached the bed.

“Now, Mr. Graves,” I shouted, “we want you to drink some of this.”

The flaccid eyelids lifted for an instant but there was no other response.  I gently opened the unresisting mouth and ladled in a couple of spoonfuls of coffee, which were immediately swallowed; whereupon I repeated the proceeding and continued at short intervals until the cup was empty.  The effect of the new remedy soon became apparent.  He began to mumble and mutter obscurely in response to the questions that I bellowed at him, and once or twice he opened his eyes and looked dreamily into my face.  Then I sat him up and made him drink some coffee from the cup, and, all the time, kept up a running fire of questions, which made up in volume of sound for what they lacked of relevancy.

Of these proceedings Mr. Weiss and his housekeeper were highly interested spectators, and the former, contrary to his usual practice, came quite close up to the bed, to get a better view.

“It is really a most remarkable thing,” he said, “but it almost looks as if you were right, after all.  He is certainly much better.  But tell me, would this treatment produce a similar improvement if the symptoms were due to disease?”

“No,” I answered, “it certainly would not.”

“Then that seems to settle it.  But it is a most mysterious affair.  Can you suggest any way in which he can have concealed a store of the drug?”

I stood up and looked him straight in the face; it was the first chance I had had of inspecting him by any but the feeblest light, and I looked at him very attentively.  Now, it is a curious fact—­though one that most persons must have observed—­that there sometimes occurs a considerable interval between the reception of a visual impression and its complete transfer to the consciousness.  A thing may be seen, as it were, unconsciously, and the impression consigned, apparently, to instant oblivion; and yet the picture may be subsequently revived by memory with such completeness that its details can be studied as though the object were still actually visible.

Something of this kind must have happened to me now.  Preoccupied as I was, by the condition of the patient, the professional habit of rapid and close observation caused me to direct a searching glance at the man before me.  It was only a brief glance—­for Mr. Weiss, perhaps embarrassed by my keen regard of him, almost immediately withdrew into the shadow—­and my attention seemed principally to be occupied by the odd contrast between the pallor of his face and the redness of his nose and by the peculiar stiff, bristly character of his eyebrows.  But there was another fact, and a very curious one, that was observed by me subconsciously and instantly forgotten, to be revived later when I reflected on the events of the night.  It was this: