The attitude of the suspicious man tends to generate in others the kind of conduct that seems to justify his suspicions. In most of us there lurks a certain strain of mischief which trustfulness disarms but distrust encourages. The inexperienced kitten which approaches us confidingly with arched back and upright tail, soliciting caresses, generally receives the gentle treatment that it expects; whereas the worldly-wise tom-cat, who, in response to friendly advances, scampers away and grins at us suspiciously from the fancied security of an adjacent wall, impels us to accelerate his retreat with a well-directed clod.  
Now the proceedings of Mr. H. Weiss resembled those of the tom-cat aforesaid and invited an analogous reply. To a responsible professional man his extraordinary precautions were at once an affront and a challenge. Apart from graver considerations, I found myself dwelling with unholy pleasure on the prospect of locating the secret hiding-place from which he seemed to grin at me with such complacent defiance; and I lost no time and spared no trouble in preparing myself for the adventure. The very hansom which bore me from the Temple to Kennington Lane was utilized for a preliminary test of Thorndyke's little apparatus. During the whole of that brief journey I watched the compass closely, noted the feel and sound of the road-material and timed the trotting of the horse. And the result was quite encouraging. It is true that the compass-needle oscillated wildly to the vibration of the cab, but still its oscillations took place around a definite point which was the average direction, and it was evident to me that the data it furnished were very fairly reliable. I felt very little doubt, after the preliminary trial, as to my being able to produce a moderately intelligible track-chart if only I should get an opportunity to exercise my skill.
 
But it looked as if I should not. Mr. Weiss's promise to send for me again soon was not fulfilled. Three days passed and still he made no sign. I began to fear that I had been too outspoken; that the shuttered carriage had gone forth to seek some more confiding and easy-going practitioner, and that our elaborate preparations had been made in vain. When the fourth day drew towards a close and still no summons had come, I was disposed reluctantly to write the case off as a lost opportunity.
 
And at that moment, in the midst of my regrets, the bottle-boy thrust an uncomely head in at the door. His voice was coarse, his accent was hideous, and his grammatical construction beneath contempt; but I forgave him all when I gathered the import of his message.
 
"Mr. Weiss's carriage is waiting, and he says will you come as quickly as you can because he's took very bad to-night."
 
I sprang from my chair and hastily collected the necessaries for the journey. The little board and the lamp I put in my overcoat pocket; I overhauled the emergency bag and added to its usual contents a bottle of permanganate of potassium which I thought I might require. Then I tucked the evening paper under my arm and went out.
 
The coachman, who was standing at the horse's head as I emerged, touched his hat and came forward to open the door.
 
"I have fortified myself for the long drive, you see," I remarked, exhibiting the newspaper as I stepped into the carriage.
 
"But you can't read in the dark," said he.
 
"No, but I have provided myself with a lamp," I replied, producing it and striking a match.
 
He watched me as I lit the lamp and hooked it on the back cushion, and observed:
 
"I suppose you found it rather a dull ride last time. It's a longish way. They might have fitted the carriage with an inside lamp. But we shall have to make it a quicker passage to-night. Governor says Mr. Graves is uncommon bad."
 
With this he slammed the door and locked it. I drew the board from my pocket, laid it on my knee, glanced at my watch, and, as the coachman climbed to his seat, I made the first entry in the little book.
 
"8.58. W. by S. Start from home. Horse 13 hands."
 
The first move of the carriage on starting was to turn round as if heading for Newington Butts, and the second entry accordingly read:
 
"8.58.30. E. by N."
 
But this direction was not maintained long. Very soon we turned south and then west and then south again. I sat with my eyes riveted on the compass, following with some difficulty its rapid changes. The needle swung to and fro incessantly but always within a definite arc, the centre of which was the true direction. But this direction varied from minute to minute in the most astonishing manner. West, south, east, north, the carriage turned, "boxing" the compass until I lost all count of direction. It was an amazing performance. Considering that the man was driving against time on a mission of life and death urgency, his carelessness as to direction was astounding. The tortuousness of the route must have made the journey twice as long as it need have been with a little more careful selection. At least so it appeared to me, though, naturally, I was not in a position to offer an authoritative criticism.
 
As far as I could judge, we followed the same route as before. Once I heard a tug's whistle and knew that we were near the river, and we passed the railway station, apparently at the same time as on the previous occasion, for I heard a passenger train start and assumed that it was the same train. We crossed quite a number of thoroughfares with tram-lines—I had no idea there were so many—and it was a revelation to me to find how numerous the railway arches were in this part of London and how continually the nature of the road-metal varied.
 
It was by no means a dull journey this time. The incessant changes of direction and variations in the character of the road kept me most uncommonly busy; for I had hardly time to scribble down one entry before the compass-needle would swing round sharply, showing that we had once more turned a corner; and I was quite taken by surprise when the carriage slowed down and turned into the covered way. Very hastily I scribbled down the final entry ("9.24. S.E. In covered way"), and having closed the book and slipped it and the board into my pocket, had just opened out the newspaper when the carriage door was unlocked and opened, whereupon I unhooked and blew out the lamp and pocketed that too, reflecting that it might be useful later.
 
As on the last occasion, Mrs. Schallibaum stood in the open doorway with a lighted candle. But she was a good deal less self-possessed this time. In fact she looked rather wild and terrified. Even by the candle-light I could see that she was very pale and she seemed unable to keep still. As she gave me the few necessary words of explanation, she fidgeted incessantly and her hands and feet were in constant movement.
 
"You had better come up with me at once," she said. "Mr. Graves is much worse to-night. We will wait not for Mr. Weiss."
 
Without waiting for a reply she quickly ascended the stairs and I followed. The room was in much the same condition as before. But the patient was not. As soon as I entered the room, a soft, rhythmical gurgle from the bed gave me a very clear warning of danger. I stepped forward quickly and looked down at the prostrate figure, and the warning gathered emphasis. The sick man's ghastly face was yet more ghastly; his eyes were more sunken, his skin more livid; "his nose was as sharp as a pen," and if he did not "babble of green fields" it was because he seemed to be beyond even that. If it had been a case of disease, I should have said at once that he was dying. He had all the appearance of a man in articulo mortis. Even as it was, feeling convinced that the case was one of morphine poisoning, I was far from confident that I should be able to draw him back from the extreme edge of vitality on which he trembled so insecurely.
 
"He is very ill? He is dying?"
 
It was Mrs. Schallibaum's voice; very low, but eager and intense. I turned, with my finger on the patient's wrist, and looked into the face of the most thoroughly scared woman I have ever seen. She made no attempt now to avoid the light, but looked me squarely in the face, and I noticed, half-unconsciously, that her eyes were brown and had a curious strained expression.
 
"Yes," I answered, "he is very ill. He is in great danger."
 
She still stared at me fixedly for some seconds. And then a very odd thing occurred. Suddenly she squinted—squinted horribly; not with the familiar convergent squint which burlesque artists imitate, but with external or divergent squint of extreme near sight or unequal vision. The effect was quite startling. One moment both her eyes were looking straight into mine; the next, one of them rolled round until it looked out of the uttermost corner, leaving the other gazing steadily forward.
 
She was evidently conscious of the change, for she turned her head away quickly and reddened somewhat. But it was no time for thoughts of personal appearance.
 
"You can save him, doctor! You will not let him die! He must not be allowed to die!"
 
She spoke with as much passion as if he had been the dearest friend that she had in the world, which I suspected was far from being the case. But her manifest terror had its uses.
 
"If anything is to be done to save him," I said, "it must be done quickly. I will give him some medicine at once, and meanwhile you must make some strong coffee."
 
"Coffee!" she exclaimed. "But we have none in the house. Will not tea do, if I make it very strong?"
 
"No, it will not. I must have coffee; and I must have it quickly."
 
"Then I suppose I must go and get some. But it is late. The shops will be shut. And I don't like leaving Mr. Graves."
 
"Can't you send the coachman?" I asked.
 
She shook her head impatiently. "No, that is no use. I must wait until Mr. Weiss comes."
 
"That won't do," I said, sharply. "He will slip through our fingers while you are waiting. You must go and get that coffee at once and bring it to me as soon as it is ready. And I want a tumbler and some water."
 
She brought me a water-bottle and glass from the wash-stand and then, with a groan of despair, hurried from the room.
 
I lost no time in applying the remedies that I had to hand. Shaking out into the tumbler a few crystals of potassium permanganate, I filled it up with water and approached the patient. His stupor was profound. I shook him as roughly as was safe in his depressed condition, but elicited no resistance or responsive movement. As it seemed very doubtful whether he was capable of swallowing, I dared not take the risk of pouring the liquid into his mouth for fear of suffocating him. A stomach-tube would have solved the difficulty, but, of course, I had not one with me. I had, however, a mouth-speculum which also acted as a gag, and, having propped the patient's mouth open with this, I hastily slipped off one of the rubber tubes from my stethoscope and inserted into one end of it a vulcanite ear-speculum to serve as a funnel. Then, introducing the other end of the tube into the gullet as far as its length would permit, I cautiously poured a small quantity of the permanganate solution into the extemporized funnel. To my great relief a movement of the throat showed that the swallowing reflex still existed, and, thus encouraged, I poured down the tube as much of the fluid as I thought it wise to administer at one time.
 
The dose of permanganate that I had given was enough to neutralize any reasonable quantity of the poison that might yet remain in the stomach. I had next to deal with that portion of the drug which had already been absorbed and was exercising its poisonous effects. Taking my hypodermic case from my bag, I prepared in the syringe a full dose of atropine sulphate, which I injected forthwith into the unconscious man's arm. And that was all that I could do, so far as remedies were concerned, until the coffee arrived.
 
I cleaned and put away the syringe, washed the tube, and then, returning to the bedside, endeavoured to rouse the patient from his profound lethargy. But great care was necessary. A little injudicious roughness of handling, and that thready, flickering pulse might stop for ever; and yet it was almost certain that if he were not speedily aroused, his stupor would gradually deepen until it shaded off imperceptibly into death. I went to work very cautiously, moving his limbs about, flicking his face and chest with the corner of a wet towel, tickling the soles of his feet, and otherwise applying stimuli that were strong without being violent.
 
So occupied was I with my efforts to resuscitate my mysterious patient that I did not notice the opening of the door, and it was with something of a start that, happening to glance round, I perceived at the farther end of the room the shadowy figure of a man relieved by two spots of light reflected from his spectacles. How long he had been watching me I cannot say, but, when he saw that I had observed him, he came forward—though not very far—and I saw that he was Mr. Weiss.
 
"I am afraid," he said, "that you do not find my friend so well to-night?"
 
"So well!" I exclaimed. "I don't find him well at all. I am exceedingly anxious about him."
 
"You don't—er—anticipate anything of a—er—anything serious, I hope?"
 
"There is no need to anticipate," said I. "It is already about as serious as it can be. I think he might die at any moment."
 
"Good God!" he gasped. "You horrify me!"
 
He was not exaggerating. In his agitation, he stepped forward into the lighter part of the room, and I could see that his face was pale to ghastliness—except his nose and the adjacent red patches on his cheeks, which stood out in grotesquely hideous contrast. Presently, however, he recovered a little and said:
 
"I really think—at least I hope—that you take an unnecessarily serious view of his condition. He has been like this before, you know."
 
I felt pretty certain that he had not, but there was no use in discussing the question. I therefore replied, as I continued my efforts to rouse the patient:
 
"That may or may not be. But in any case there comes a last time; and it may have come now."
 
"I hope not," he said; "although I understand that these cases always end fatally sooner or later."
 
"What cases?" I asked.
 
"I was referring to sleeping sickness; but perhaps you have formed some other opinion as to the nature of this dreadful complaint."
 
I hesitated for a moment, and he continued: "As to your suggestion that his symptoms might be due to drugs, I think we may consider that as disposed of. He has been watched, practically without cessation since you came last, and, moreover, I have myself turned out the room and examined the bed and have not found a trace of any drug. Have you gone into the question of sleeping sickness?"
 
I looked at the man narrowly before answering, and distrusted him more than ever. But this was no time for reticence. My concern was with the patient and his present needs. After all, I was, as Thorndyke had said, a doctor, not a detective, and the circumstances called for straightforward speech and action on my part.
 
"I have considered that question," I said, "and have come to a perfectly definite conclusion. His symptoms are not those of sleeping sickness. They are in my opinion undoubtedly due to morphine poisoning."
 
"But my dear sir!" he exclaimed, "the thing is impossible! Haven't I just told you that he has been watched continuously?"
 
"I can only judge by the appearances that I find," I answered; and, seeing that he was about to offer fresh objections, I continued: "Don't let us waste precious time in discussion, or Mr. Graves may be dead before we have reached a conclusion. If you will hurry them up about the coffee that I asked for some time ago, I will take the other necessary measures, and perhaps we may manage to pull him round."
 
The rather brutal decision of my manner evidently daunted him. It must have been plain to him that I was not prepared to accept any explanation of the unconscious man's condition other than that of morphine poisoning; whence the inference was pretty plain that the alternatives were recovery or an inquest. Replying stiffly that I "must do as I thought best," he hurried from the room, leaving me to continue my efforts without further interruption.
 
For some time these efforts seemed to make no impression. The man lay as still and impassive as a corpse excepting for the slow, shallow and rather irregular breathing with its ominous accompanying rattle. But presently, by imperceptible degrees, signs of returning life began to make their appearance. A sharp slap on the cheek with the wet towel produced a sensible flicker of the eyelids; a similar slap on the chest was followed by a slight gasp. A pencil, drawn over the sole of the foot, occasioned a visible shrinking movement, and, on looking once more at the eyes, I detected a slight change that told me that the atropine was beginning to take effect.
 
This was very encouraging, and, so far, quite satisfactory, though it would have been premature to rejoice. I kept the patient carefully covered and maintained the process of gentle irritation, moving his limbs and shoulders, brushing his hair and generally bombarding his deadened senses with small but repeated stimuli. And under this treatment, the improvement continued so far that on my bawling a question into his ear he actually opened his eyes for an instant, though in another moment, the lids had sunk back into their former position.
 
Soon after this, Mr. Weiss re-entered the room, followed by Mrs. Schallibaum, who carried a small tray, on which were a jug of coffee, a jug of milk, a cup and saucer and a sugar basin.
 
"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:
 
As Mr. Weiss stood, with his head slightly turned, I was able to look through one glass of his spectacles at the wall beyond. On the wall was a framed print; and the edge of the frame, seen through the spectacle-glass, appeared quite unaltered and free from distortion, magnification or reduction, as if seen through plain window-glass; and yet the reflections of the candle-flame in the spectacles showed the flame upside down, proving conclusively that the glasses were concave on one surface at least. The strange phenomenon was visible only for a moment or two, and as it passed out of my sight it passed also out of my mind.
 
"No," I said, replying to the last question; "I can think of no way in which he could have effectually hidden a store of morphine. Judging by the symptoms, he has taken a large dose, and, if he has been in the habit of consuming large quantities, his stock would be pretty bulky. I can offer no suggestion whatever."
 
"I suppose you consider him quite out of danger now?"
 
"Oh, not at all. I think we can pull him round if we persevere, but he must not be allowed to sink back into a state of coma. We must keep him on the move until the effects of the drug have really passed off. If you will put him into his dressing-gown we will walk him up and down the room for a while."
 
"But is that safe?" Mr. Weiss asked anxiously.
 
"Quite safe," I answered. "I will watch his pulse carefully. The danger is in the possibility, or rather certainty, of a relapse if he is not kept moving."
 
With obvious unwillingness and disapproval, Mr. Weiss produced a dressing-gown and together we invested the patient in it. Then we dragged him, very limp, but not entirely unresisting, out of bed and stood him on his feet. He opened his eyes and blinked owlishly first at one and then at the other of us, and mumbled a few unintelligible words of protest; regardless of which, we thrust his feet into slippers and endeavoured to make him walk. At first he seemed unable to stand, and we had to support him by his arms as we urged him forward; but presently his trailing legs began to make definite walking movements, and, after one or two turns up and down the room, he was not only able partly to support his weight, but showed evidence of reviving consciousness in more energetic protests.
 
At this point Mr. Weiss astonished me by transferring the arm that he held to the housekeeper.
 
"If you will excuse me, doctor," said he, "I will go now and attend to some rather important business that I have had to leave unfinished. Mrs. Schallibaum will be able to give you all the assistance that you require, and will order the carriage when you think it safe to leave the patient. In case I should not see you again I will say 'good night.' I hope you won't think me very unceremonious."
 
He shook hands with me and went out of the room, leaving me, as I have said, profoundly astonished that he should consider any business of more moment than the condition of his friend, whose life, even now, was but hanging by a thread. However, it was really no concern of mine. I could do without him, and the resuscitation of this unfortunate half-dead man gave me occupation enough to engross my whole attention.
 
The melancholy progress up and down the room re-commenced, and with it the mumbled protests from the patient. As we walked, and especially as we turned, I caught frequent glimpses of the housekeeper's face. But it was nearly always in profile. She appeared to avoid looking me in the face, though she did so once or twice; and on each of these occasions her eyes were directed at me in a normal manner without any sign of a squint. Nevertheless, I had the impression that when her face was turned away from me she squinted. The "swivel eye"—the left—was towards me as she held the patient's right arm, and it was almost continuously turned in my direction, whereas I felt convinced that she was really looking straight before her, though, of course, her right eye was invisible to me. It struck me, even at the time, as an odd affair, but I was too much concerned about my charge to give it much consideration.
 
Meanwhile the patient continued to revive apace. And the more he revived, the more energetically did he protest against this wearisome perambulation. But he was evidently a polite gentleman, for, muddled as his faculties were, he managed to clothe his objections in courteous and even gracious forms of speech singularly out of agreement with the character that Mr. Weiss had given him.
 
"I thangyou," he mumbled thickly. "Ver' good take s'much trouble. Think I will lie down now." He looked wistfully at the bed, but I wheeled him about and marched him once more down the room. He submitted unresistingly, but as we again approached the bed he reopened the matter.
 
"S'quite s'fficient, thang you. Gebback to bed now. Much 'bliged frall your kindness"—here I turned him round—"no, really; m'feeling rather tired. Sh'like to lie down now, f'you'd be s'good."
 
"You must walk about a little longer, Mr. Graves," I said. "It would be very bad for you to go to sleep again."
 
He looked at me with a curious, dull surprise, and reflected awhile as if in some perplexity. Then he looked at me again and said:
 
"Thing, sir, you are mistake—mistaken me—mist—"
 
Here Mrs. Schallibaum interrupted sharply:
 
"The doctor thinks it's good for you to walk about. You've been sleeping too much. He doesn't want you to sleep any more just now."
 
"Don't wanter sleep; wanter lie down," said the patient.
 
"But you mustn't lie down for a little while. You must walk about for a few minutes more. And you'd better not talk. Just walk up and down."
 
"There's no harm in his talking," said I; "in fact it's good for him. It will help to keep him awake."
 
"I should think it would tire him," said Mrs. Schallibaum; "and it worries me to hear him asking to lie down when we can't let him."
 
She spoke sharply and in an unnecessarily high tone so that the patient could not fail to hear. Apparently he took in the very broad hint contained in the concluding sentence, for he trudged wearily and unsteadily up and down the room for some time without speaking, though he continued to look at me from time to time as if something in my appearance puzzled him exceedingly. At length his intolerable longing for repose overcame his politeness and he returned to the attack.
 
"Surely v' walked enough now. Feeling very tired. Am really. Would you be s'kind 's t'let me lie down few minutes?"
 
"Don't you think he might lie down for a little while?" Mrs. Schallibaum asked.
 
I felt his pulse, and decided that he was really becoming fatigued, and that it would be wiser not to overdo the exercise while he was so weak. Accordingly, I consented to his returning to bed, and turned him round in that direction; whereupon he tottered gleefully towards his resting-place like a tired horse heading for its stable.
 
As soon as he was tucked in, I gave him a full cup of coffee, which he drank with some avidity as if thirsty. Then I sat down by the bedside, and, with a view to keeping him awake, began once more to ply him with questions.
 
"Does your head ache, Mr. Graves?" I asked.
 
"The doctor says 'does your head ache?'" Mrs. Schallibaum squalled, so loudly that the patient started perceptibly.
 
"I heard him, m'dear girl," he answered with a faint smile. "Not deaf you know. Yes. Head aches a good deal. But I thing this gennleman mistakes—"
 
"He says you are to keep awake. You mustn't go to sleep again, and you are not to close your eyes."
 
"All ri' Pol'n. Keep'm open," and he proceeded forthwith to shut them with an air of infinite peacefulness. I grasped his hand and shook it gently, on which he opened his eyes and looked at me sleepily. The housekeeper stroked his head, keeping her face half-turned from me—as she had done almost constantly, to conceal the squinting eye, as I assumed—and said:
 
"Need we keep you any longer, doctor? It is getting very late and you have a long way to go."
 
I looked doubtfully at the patient. I was loath to leave him, distrusting these people as I did. But I had my work to do on the morrow, with, perhaps, a night call or two in the interval, and the endurance even of a general practitioner has its limits.
 
"I think I heard the carriage some time ago," Mrs. Schallibaum added.
 
I rose hesitatingly and looked at my watch. It had turned half-past eleven.
 
"You understand," I said in a low voice, "that the danger is not over? If he is left now he will fall asleep, and in all human probability will never wake. You clearly understand that?"
 
"Yes, quite clearly. I promise you he shall not be allowed to fall asleep again."
 
As she spoke, she looked me full in the face for a few moments, and I noted that her eyes had a perfectly normal appearance, without any trace whatever of a squint.
 
"Very well," I said. "On that understanding I will go now; and I shall hope to find our friend quite recovered at my next visit."
 
I turned to the patient, who was already dozing, and shook his hand heartily.
 
"Good-bye, Mr. Graves!" I said. "I am sorry to have to disturb your repose so much; but you must keep awake, you know. Won't do to go to sleep."
 
"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.
 
But when I came to think about it I remembered that Mrs. Schallibaum had shown some anxiety to prevent the patient from talking. She had interrupted him more than once, and had on two occasions broken in when he seemed to be about to ask me some question. I was "mistaken" about something. What was that something that he wanted to tell me?
 
It had struck me as singular that there should be no coffee in the house, but a sufficiency of tea. Germans are not usually tea-drinkers and they do take coffee. But perhaps there was nothing in this. Rather more remarkable was the invisibility of the coachman. Why could he not be sent to fetch the coffee, and why did not he, rather than the housekeeper, come to take the place of Mr. Weiss when the latter had to go away.
 
There were other points, too. I recalled the word that sounded like "Pol'n," which Mr. Graves had used in speaking to the housekeeper. Apparently it was a Christian name of some kind; but why did Mr. Graves call the woman by her Christian name when Mr. Weiss addressed her formally as Mrs. Schallibaum? And, as to the woman herself: what was the meaning of that curious disappearing squint? Physically it presented no mystery. The woman had an ordinary divergent squint, and, like many people, who suffer from this displacement, could, by a strong muscular effort, bring the eyes temporarily into their normal parallel position. I had detected the displacement when she had tried to maintain the effort too long, and the muscular control had given way. But why had she done it? Was it only feminine vanity—mere sensitiveness respecting a slight personal disfigurement? It might be so; or there might be some further motive. It was impossible to say.
 
Turning this question over, I suddenly remembered the peculiarity of Mr. Weiss's spectacles. And here I met with a real poser. I had certainly seen through those spectacles as clearly as if they had been plain window-glass; and they had certainly given an inverted reflection of the candle-flame like that thrown from the surface of a concave lens. Now they obviously could not be both flat and concave; but yet they had the properties peculiar to both flatness and concavity. And there was a further difficulty. If I could see objects unaltered through them, so could Mr. Weiss. But the function of spectacles is to alter the appearances of objects, by magnification, reduction or compensating distortion. If they leave the appearances unchanged they are useless. I could make nothing of it. After puzzling over it for quite a long time, I had to give it up; which I did the less unwillingly inasmuch as the construction of Mr. Weiss's spectacles had no apparent bearing on the case.
 
On arriving home, I looked anxiously at the message-book, and was relieved to find that there were no further visits to be made. Having made up a mixture for Mr. Graves and handed it to the coachman, I raked the ashes of the surgery fire together and sat down to smoke a final pipe while I reflected once more on the singular and suspicious case in which I had become involved. But fatigue soon put an end to my meditations; and having come to the conclusion that the circumstances demanded a further consultation with Thorndyke, I turned down the gas to a microscopic blue spark and betook myself to bed.