THE fog swirled slowly round him, driven by a heavy movement of its own, for of course there was no wind. It hung in poisonous thick coils and loops; it rose and sank; no light penetrated it directly from street-lamp or motor-car, though here and there some big shop-window shed a glimmering patch upon its ever-shifting curtain.

O'Reilly's eyes ached and smarted with the incessant effort to see a foot beyond his face. The optic nerve grew tired, and sight, accordingly, less accurate. He coughed as he shuffled forward cautiously through the choking gloom. Only the stifled rumble of crawling traffic persuaded him he was in a crowded city at all— this, and the vague outlines of groping figures, hugely magnified, emerging suddenly and disappearing again, as they fumbled along inch by inch towards uncertain destinations.

The figures, however, were human beings; they were real. That much he knew. He heard their muffled voices, now close, now distant, strangely smothered always. He also heard the tapping of innumerable sticks, feeling for iron railings or the curb. These phantom outlines represented living people. He was not alone.

It was the dread of finding himself quite alone that haunted him, for he was still unable to cross an open space without assistance. He had the physical strength, it was the mind that failed him. Midway the panic terror might descend upon him, he would shake all over, his will dissolve, he would shriek for help, run wildly—into the traffic probably— or, as they called it in his North Ontario home, "throw a fit" in the street before advancing wheels. He was not yet entirely cured, although under ordinary conditions he was safe enough, as Dr. Henry had assured him.

When he left Regent's Park by Tube an hour ago the air was clear, the November sun shone brightly, the pale blue sky was cloudless, and. The assumption that he could manage the journey across London Town alone was justified. The following day he was to leave for Brighton for the week of final convalescence: this little preliminary test of his powers on a bright November afternoon was all to the good. Doctor Henry furnished minute instructions:

"You change at Piccadilly Circus—without leaving the underground station, mind—and get out at South Kensington. You know the address of your V. A. D. friend. Have your cup of tea with her, then come back the same way to Regent's Park. Come back before dark; say six o'clock at latest. It's better." He had described exactly what turns to take after leaving the station, so many to the right, so many to the left; it was a little confusing, but the distance was short. "You can always ask. You can't possibly go wrong."

The unexpected fog, however, now blurred these instructions in a confused jumble in his mind. The failure of outer sight reacted upon memory. The V. A. D. besides had warned him that her address was "not easy to find the first time. The house lies in a backwater. But with your 'backwoods' instincts you'll probably manage it better than any Londoner!" She, too, had not calculated upon the fog.

When O'Reilly came up the stairs at South Kensington Station, he emerged into such murky darkness that he thought he was still underground. An impenetrable world lay round him. Only a raw bite in the damp atmosphere told him he stood beneath an open sky. For some little time he stood and stared,a Canadian soldier, his home among clear brilliant spaces, now face to face for the first time in his life with that thing he had so often read about, a bad London fog. With keenest interest and surprise he enjoyed the novel spectacle for perhaps ten minutes, watching the people arrive and vanish, and wondering why the station lights stopped dead the instant they touched the street, then, with a sense of adventure—it cost an effort—he left the covered building and plunged into the opaque sea beyond.

Repeating to himself the directions he had received—first to the right, second to the left, once more to the left, and so forth,—he checked each turn, assuring himself it was impossible to go wrong. He made correct if slow progress, until someone blundered into him with an abrupt and startling question: "Is this right, do you know, for South Kensington Station?"

It was the suddenness that startled him; one moment there was no one, the next they were face to face, another, and the stranger had vanished into the gloom with a courteous word of grateful thanks. But the little shock of interruption had put memory out of gear. Had he already turned twice to the right, or had he not? O'Reilly realised sharply he had forgotten his memorized instructions. He stood still, making strenuous efforts at recovery, but each effort left him more uncertain than before. Five minutes later he was lost as hopelessly as any townsman who leaves his tent in the backwoods without blazing the trees to ensure finding his way back again. Even the sense of direction, so strong in him among his native forests, was completely gone. There were no stars, there was no wind, no smell, no sound of running water. There was nothing anywhere to guide him, nothing but occasional dim outlines, groping, shuffling, emerging and disappearing in the eddying fog, but rarely coming within actual speaking, much less touching, distance. He was lost utterly; more, he was alone.

Yet not quite alone—the thing he dreaded most. There were figures still in his immediate neighborhood. They emerged, vanished, reappeared, dissolved. No, he was not quite alone. He saw these thickenings of the fog, he heard their voices, the tapping of their cautious sticks, their shuffling feet as well. They were real. They moved, it seemed, about him in a circle, never coming very close.

"But they 're real," he said to himself aloud, betraying the weak point in his armor. "They 're human beings right enough. I'm positive of that."

He had never argued with Dr. Henry. He wanted to get well; he had obeyed implicitly, believing everything the doctor told him—up to a point. But he had always had his own idea about these "figures," because, among them, were often enough his own pals from the Somme, Gallipoli, the Mespot horror, too. And he ought to know his own pals when he saw them! At the same time he knew quite well he had been "shocked," his being dislocated, half dissolved as it were, his system pushed into some lopsided condition that meant inaccurate registration. True. He grasped that perfectly. But, in that shock and dislocation, had he not possibly picked up another gear? Were there not gaps and broken edges, pieces that no longer dovetailed, fitted as usual, interstices, in a word? Yes, that was the word—interstices. Cracks, so to speak, between his perception of the outside world and his inner interpretation of these? Between memory and recognition? Between the various states of consciousness that usually dovetailed so neatly that the joints were normally imperceptible?

His state, he well knew, was abnormal, but were his symptoms on that account unreal? Could not these interstices be used by—others? When he saw his "figures," he used to ask himself: "Are not these the real ones, and the others—the human beings, unreal?"

This question now revived in him with a new intensity. Were these figures in the fog real or unreal? The man who had asked the way to the station, was he not, after all, a shadow merely?

By the use of his cane and foot and what of sight was left to him he knew that he was on an island. A lamp-post stood up solid and straight beside him, shedding its faint patch of glimmering light. Yet there were railings, however, that puzzled him, for his stick hit the metal rods distinctly in a series. And there should be no railings round an island. Yet he had most certainly crossed a dreadful open space to get where he was. His confusion and bewilderment increased with dangerous rapidity. Panic was not far away.

He was no longer on an omnibus route. A rare taxi crawled past occasionally, a whitish patch at the window indicating an anxious human face; now and again came a van or cart, the driver holding a lantern as he led the stumbling horse. These comforted him, rare though they were. But it was the figures that drew his attention most. He was quite sure they were real. They were human beings like himself.

For all that, he decided he might as well be positive on the point. He tried one accordingly, a big man who rose suddenly before him out of the very earth.

"Can you give me the trail to Morley Place?" he asked.

But his question was drowned by the other's simultaneous inquiry in a voice much louder than his own.

"I say, is this right for the Tube station, d' you know? I'm utterly lost. I want South Ken."

And by the time O'Reilly had pointed the direction whence he himself had just come, the man was gone again, obliterated, swallowed up, not so much as his footsteps audible, almost as if—it seemed again—he never had been there at all.

This left an acute unpleasantness in him, a sense of bewilderment greater than before. He waited five minutes, not daring to move a step, then tried another figure, a woman this time, who, luckily, knew the immediate neighborhood intimately. She gave him elaborate instructions in the kindest possible way, then vanished with incredible swiftness and ease into the sea of gloom beyond. The instantaneous way she vanished was disheartening, upsetting: it was so uncannily abrupt and sudden. Yet she comforted him. Morley Place, according to her version, was not two hundred yards from where he stood. He felt his way forward, step by step, using his cane, crossing a giddy open space, kicking the curb with each boot alternately, coughing and choking all the time as he did so.

"They were real, I guess, anyway," he said aloud. "They were both real enough all right. And it may lift a bit soon!" He was making a great effort to hold himself in hand. He was already fighting, that is; he realized this perfectly. The only point was the reality of the figures. "It may lift now any minute," he repeated louder. In spite of the cold, his skin was sweating profusely.

But, of course, it did not lift. The figures, too, became fewer. No carts were audible. He had followed the woman's directions carefully, but now found himself in some byway, evidently, where pedestrians at the best of times were rare. There was dull silence all about him. His foot lost the curb, his cane swept the empty air, striking nothing solid, and panic rose upon him with its shuddering, icy grip. He was alone, he knew himself alone, worse still, he was in another open space.

It took him fifteen minutes to cross that open space, most of the way upon his hands and knees, oblivious of the icy slime that stained his trousers, froze his fingers, intent only upon feeling solid support against his back and spine again. It was an endless period. The moment of collapse was close, the shriek already rising in his throat, the shaking of the whole body uncontrollable, when his outstretched fingers struck a friendly curb, and he saw a glimmering patch of diffused radiance overhead. With a great, quick effort he stood upright, and an instant later his stick rattled along an area railing. He leaned against it, breathless, panting, his heart beating painfully while the street-lamp gave him the further comfort of its feeble gleam, the actual flame, however, invisible. He looked this way and that; the pavement was deserted. He was engulfed in the dark silence of the fog.

But Morley Place, he knew, must be very close by now. He thought of the friendly little V. A. D. he had known in France, of a warm bright fire, a cup of tea and a cigarette. One more effort, he reflected, and all these would be his. He pluckily groped his way forward again, crawling slowly by the area railings. If things got really bad again, he would ring a bell and ask for help, much as he shrank from the idea. Provided he had no more open spaces to cross, provided he saw no more figures emerging and vanishing like creatures born of the fog and dwelling within it as within their native element—it was the figures he now dreaded more than anything else, more than even the loneliness,—provided the panic sense—

A faint darkening of the fog beneath the next lamp caught his eye and made him start. He stopped. It was not a figure this time; it was the shadow of the pole grotesquely magnified. No, it moved. It moved towards him. A flame of fire followed by ice flowed through him. It was a figure close against his face. It was a woman.

The doctor's advice came suddenly back to him, the counsel that had cured him of a hundred phantoms:

"Do not ignore them. Treat them as real. Speak and go with them. You will soon prove their unreality then. And they will leave you."

He made a brave, tremendous effort. He was shaking. One hand clutched the damp and icy area railing.

"Lost your way like myself, have n't you, ma'am?" he said in a voice that trembled. "Do you know where we are at all? Morley Place I'm looking for—"

He stopped dead. The woman moved nearer and for the first time he saw her face clearly. Its ghastly pallor, the bright, frightened eyes that stared with a kind of dazed bewilderment into his own, the beauty, above all, arrested his speech midway. The woman was young, her tall figure wrapped in a dark fur coat.

"Can I help you?" he asked impulsively, forgetting his own terror for the moment. He was more than startled. Her air of distress and pain stirred a peculiar anguish in him. For a moment she made no answer, thrusting her white face closer as if examining him, so close, indeed, that he controlled with difficulty his instinct to shrink back a little.

"Where am I?" she asked at length, searching his eyes intently. "I'm lost; I 've lost myself. I can't find my way back." Her voice was low, a curious wailing in it that touched his pity oddly. He felt his own distress merging in one that was greater.

"Same here," he replied more confidently. "I'm terrified of being alone, too. I 've had shell-shock, you know. Let's go together. We 'll find a way together."

"Who are you?" the woman murmured, still staring at him with her big bright eyes, their distress, however, no whit lessened. She gazed at him as though aware suddenly of his presence.

He told her briefly. "And I'm going to tea with a V. A. D. friend in Morley Place. What's your address? Do you know the name of the street?"

She appeared not to hear him, or not to understand exactly; it was as if she was not listening again.

"I came out so suddenly, so unexpectedly," he heard the low voice with pain in every syllable; "I can't find my way home again. Just when I was expecting him too." She looked about her with a distraught expression that made O'Reilly long to carry her in his arms to safety then and there. "He may be there now—waiting for me at this very moment—and I can't get back." And so sad was her voice that only by an effort did O'Reilly prevent himself putting out his hand to touch her. More and more he forgot himself in his desire to help her. Her beauty, the wonder of her strange bright eyes in the pallid face, made an immense appeal. He became calmer. This woman was real enough. He asked again the address, the street and number, the distance she thought it was.

"Have you any idea of the direction, ma'am, any idea at all? We 'll go together and——"

She suddenly cut him short. She turned her head as if to listen, so that he saw her profile a moment, the outline of the slender neck, a glimpse of jewels just below the fur.

"Hark! I hear him calling! I remember!" And she was gone from his side into the swirling fog.

Without an instant's hesitation O'Reilly followed her, not only because he wished to help, but because he dared not be left alone. The presence of this strange, lost woman comforted him; he must not lose sight of her, whatever happened. He had to run, she went so rapidly, ever just in front, moving with confidence and certainty, turning right and left, crossing the street, but never stopping, never hesitating, her companion always at her heels in breathless haste, and with a growing terror that he might lose her any minute. The way she found her direction through the dense fog was marvelous enough, but O'Reilly's only thought was to keep her in sight, lest his own panic redescend upon him with its inevitable collapse in the dark and lonely street. It was a wild and panting pursuit, and he kept her in view with difficulty, a dim fleeting outline always a few yards ahead of him. She did not once turn her head, she uttered no sound, no cry; she hurried forward with unfaltering instinct. Nor did the chase occur to him once as singular; she was his safety, and that was all he realized.

One thing, however, he remembered afterwards, though at the actual time he no more than registered the detail, paying no attention to it—a definite perfume she left upon the atmosphere, one, moreover, that he knew, although he could not find its name as he ran. It was associated vaguely, for him, with something unpleasant, something disagreeable. He connected it with misery and pain. It gave him a feeling of uneasiness. More than that he did not notice at the moment, nor could he remember—he certainly did not try—where he had known this particular scent before.

Then suddenly the woman stopped, opened a gate and passed into a small private garden—so suddenly that O'Reilly, close upon her heels, only just avoided tumbling into her.

"You 've found it?" he cried. "May I come in a moment with you? Perhaps you 'll let me telephone to the doctor?"

She turned instantly. Her face, close against his own, was livid.

"Doctor!" she repeated in an awful whisper. The word meant terror to her. O'Reilly stood amazed. For a second or two neither of them moved. The woman seemed petrified.

"Dr. Henry, you know," he stammered, finding his tongue again. "I'm in his care. He's in Harley Street."

Her face cleared as suddenly as it had darkened, though the original expression of bewilderment and pain still hung in her great eyes. But the terror left them, as though she suddenly forgot some association that had revived it.

"My home," she murmured. "My home is somewhere here. I'm near it. I must get back—in time—for him. I must. He's coming to me." And with these extraordinary words she turned, walked up the narrow path, and stood upon the porch of a two-story house before her companion had recovered from his astonishment sufficiently to move or utter a syllable in reply. The front door, he saw, was ajar. It had been left open.

For five seconds, perhaps for ten, he hesitated; it was the fear that the door would close and shut him out that brought the decision to his will and muscles. He ran up the steps and followed the woman into a dark hall where she had already preceded him, and amid whose blackness she now had finally vanished. He closed the door, not knowing exactly why he did so, and knew at once by an instinctive feeling that the house he now found himself in with this unknown woman was empty and unoccupied. In a house, however, he felt safe. It was the open streets that were his danger. He stood waiting, listening a moment before he spoke; and he heard the woman moving down the passage from door to door, repeating to herself in her low voice of unhappy wailing some words he could not understand:

"Where is it? Oh, where is it? I must get back!"

O'Reilly then found himself abruptly stricken with dumbness, as though, with these strange words, a haunting terror came up and breathed against him in the darkness.

"Is she after all a figure?" ran in letters of fire across his numbed brain. "Is she unreal—or real?"

Seeking relief in action of some kind he put out a hand automatically, feeling along the wall for an electric switch, and though he found it by some miraculous chance, no answering glow responded to the click.

And the woman's voice from the darkness:

"Ah! Ah! At last I've found it. I'm home again—at last!" He heard a door open and close upstairs. He was on the ground floor now—alone. Complete silence followed.

In the conflict of various emotions—fear for himself lest his panic should return, fear for the woman who had led him into this empty house and now deserted him upon some mysterious errand of her own that made him think of madness, in this conflict that held him a moment spellbound, there was a yet bigger ingredient demanding instant explanation, but an explanation that he could not find. Was the woman real or was she unreal? Was she a human being or a "figure"? The horror of doubt obsessed him with an acute uneasiness that betrayed itself in a return of that unwelcome inner trembling he knew was dangerous.

What saved him from a crise that must have had most dangerous results for his mind and nervous system generally, seems to have been the outstanding fact that he felt more for the woman than for himself. His sympathy and pity had been deeply moved; her voice, her beauty, her anguish and bewilderment, all uncommon, inexplicable, mysterious, formed together a claim that drove self into the background. Added to this was the detail that she had left him, gone to another floor without a word, and now, behind a closed door in a room up-stairs, found herself face to face at last with the unknown object of her frantic search—with "it," whatever "it" might be. Real or unreal, figure or human being, the overmastering impulse of his being was that he must go to her.

It was this clear impulse that gave him decision and energy to do what he then did. He struck a match, he found a stump of candle, he made his way by means of this flickering light along he passage and up the carpetless stairs. He moved cautiously, stealthily, though not knowing why he did so. The house, he now saw, was indeed untenanted; dust-sheets covered the piled-up furniture; he glimpsed, through doors ajar, pictures screened upon the walls, brackets draped to look like hooded heads. He went on slowly, steadily, moving on tiptoe as though conscious of being watched, noting the well of darkness in the hall below, the grotesque shadows that his movements cast on walls and ceiling. The silence was unpleasant, yet, remembering hat the woman was "expecting" someone, he did not wish it broken. He reached the landing and stood still. Closed doors on both sides of a corridor met his sight, as he shaded the candle to examine the scene. Behind which of these doors, he asked himself, was the woman, figure or human being, now alone with "it".

There was nothing to guide him, but an instinct that he must not delay sent him forward again upon his search. He tried a door on the right—an empty room, with the furniture hidden by dustsheets, and the mattress rolled up on the bed. He tried second door, leaving the first one open behind him, and it was, similarly, an empty bedroom. Coming out into the corridor again he stood a moment waiting, then called aloud in a low voice that yet woke echoes unpleasantly in the hall below:

"Where are you? I want to help. Which room are you in?"

There was no answer; he was almost glad he heard no sound, he knew quite well that he was waiting really for another sound—the steps of him who was "expected." And the idea of meeting with this unknown third sent a shudder through him, as though related to an interview he dreaded with his whole heart, and must at all costs avoid. Waiting another moment or two, he noted that his candle-stump was burning low, then crossed the landing with a feeling, at once of hesitation and determination, towards a door opposite to him. He opened it; he did not halt on the threshold. Holding the candle at arm's-length, he went boldly in.

And instantly his nostrils told him he was right at last, for a whiff of the strange perfume, though this time much stronger than before, greeted him, sending a new quiver along his nerves. He knew now why it was associated with unpleasantness, with pain, with misery, for he recognized it—the odor of a hospital. In this room a powerful anesthetic had been used, and recently.

Simultaneously with smell, sight brought its message too. On the large double bed behind the door on his right lay, to his amazement, the woman in the dark fur coat. He saw the jewels on the slender neck; but the eyes he did not see, for they were closed—closed too, he grasped at once, in death. The body lay stretched at full length, quite motionless. He approached. A dark thin streak that came from the parted lips and passed downwards over the chin, losing itself then in the fur collar, was a trickle of blood. It was hardly dry. It glistened.

Strange it was, perhaps, that, while imaginary fears had the power to paralyze him in mind and body, this sight of something real had the effect of restoring confidence. The sight of blood and death, amid conditions often ghastly and even monstrous, was no new thing to him. He went up quietly, and with steady hand he felt the woman's cheek, the warmth of recent life still in its softness. The final cold had not yet mastered this empty form whose beauty, in its perfect stillness, had taken on the new strange sweetness of an unearthly bloom. Pallid, silent, untenanted, it lay before him, lit by the flicker of his guttering candle. He lifted the fur coat to feel for the unbeating heart. A couple of hours ago at most, he judged, this heart was working busily, the breath came through those parted lips, the eyes were shining in full beauty. His hand encountered a hard knob—the head of a long steel hat-pin driven through the heart up to its hilt.

He knew then which was the figure, which was the real and which the unreal. He knew also what had been meant by "it."

But before he could think or reflect what action he must take, before he could straighten himself even from his bent position over the body on the bed, there sounded through the empty house below the loud clang of the front door being closed. And instantly rushed over him that other fear he had so long forgotten—fear for himself. The panic of his own shaken nerves descended with irresistible onslaught. He turned, extinguishing the candle in the violent trembling of his hand, and tore headlong from the room.

The following ten minutes seemed a nightmare in which he was not master of himself and knew not exactly what he did. All he realized was that steps already sounded on the stairs, coming quickly nearer. The flicker of an electric torch played on the banisters, whose shadows ran swiftly sideways along the wall as the hand that held the light ascended. He thought in a frenzied second of police, of his presence in the house, of the murdered woman. It was a sinister combination. Whatever happened, he must escape without being so much as even seen. His heart raced madly. He darted across the landing into the room opposite, whose door he had luckily left open. By some incredible chance, apparently, he was neither seen nor heard by the man who, a moment later, reached the landing, entered the room where the body of the woman lay, and closed the door carefully behind him.

Shaking, scarcely daring to breathe lest his breath be audible, O'Reilly, in the grip of his own personal terror, remnant of his uncured shock of war, had no thought of what duty might demand or not demand of him. He thought only of himself. He realized one clear issue—that he must get out of the house without being heard or seen. Who the new-comer was he did not know, beyond an uncanny assurance that it was not him whom the woman had "expected," but the murderer himself, and that it was the murderer, in his turn, who was expecting this third person. In that room with death at his elbow, a death he had himself brought about but an hour or two ago, the murderer now hid in waiting for his second victim. And the door was closed.

Yet any minute it might open again, cutting off retreat.

O'Reilly crept out, stole across the landing, reached the head of the stairs, and began with the utmost caution the perilous descent. Each time the bare boards creaked beneath his weight, no matter how stealthily this weight was adjusted, his heart missed a beat. He tested each step before he pressed upon it, distributing as much of his weight as he dared upon the banisters. It was a little more than half-way down that, to his horror, his foot caught in a projecting carpet tack; he slipped on the polished wood, and only saved himself from falling headlong by a wild clutch at the railing, making an uproar that seemed to him like the explosion of a hand-grenade in the forgotten trenches. His nerves gave way then, and panic seized him. In the silence that followed the resounding echoes he heard the bedroom door opening on the floor above.

Concealment was now useless. It was impossible, too. He took the last flight of stairs in a series of leaps, four steps at a time, reached the hall, flew across it, and opened the front door, just as his pursuer, electric torch in hand, covered half the stairs behind him. Slamming the door, he plunged headlong into the welcome, all-obscuring fog outside.

The fog had now no terrors for him, he welcomed its concealing mantle; nor did it matter in which direction he ran so long as he put distance between him and the house of death. The pursuer had, of course, not followed him into the street. He crossed open spaces without a tremor. He ran in a circle nevertheless, though without being aware he did so. No people were about, no single groping shadow passed him, no boom of traffic reached his ears, when he paused for breath at length against an area railing. Then for the first time he made the discovery that he had no hat. He remembered now. In examining the body, partly out of respect, partly perhaps unconsciously, he had taken it off and laid it—on the very bed.

It was there, a telltale bit of damning evidence, in the house of death. And a series of probable consequences flashed through his mind like lightning. It was a new hat fortunately; more fortunate still, he had not yet written name or initials in it; but the maker's mark was there for all to read, and the police would go immediately to the shop where he had bought it only two days before. Would the shop people remember his appearance? Would his visit, the date, the conversation be recalled? He thought it was unlikely; he resembled dozens of men; he had no outstanding peculiarity. He tried to think, but his mind was confused and troubled, his heart was beating dreadfully, he felt desperately ill. He sought vainly for some story to account for his being out in the fog and far from home without a hat. No single idea presented itself. He clung to the icy railings, hardly able to keep upright, collapse very near—when suddenly a figure emerged from the fog, paused a moment to stare at him, put out a hand and caught him, and then spoke.

"You 're ill, my dear sir," said a man's kindly voice. "Can I be of any assistance? Come, let me help you." He had seen at once that it was not a case of drunkenness. "Come, take my arm, won't you? I'm a physician. Luckily, too, you are just outside my very house. Come in." And he half dragged, half pushed O'Reilly, now bordering on collapse, up the steps and opened the door with his latch-key.

You

"I'm sure of that," offered the other readily.

"A colleague of mine, now dead, as I mentioned, a surgeon, with a big practice, married a young and charming girl. They lived happily together for several years. His wealth made her very comfortable. His consulting room, I must tell you, was some distance from his house,just as this might be, so that she was never bothered with any of his cases. Then came the war. Like many others, though much over age, he volunteered. He gave up his lucrative practice and went to South Africa. His income, of course, stopped; the big house was closed; his wife found her life of enjoyment considerably curtailed. This she considered a great hardship, it seems. She felt a bitter grievance against him. Devoid of imagination, without any power of sacrifice, a selfish type, she was yet a beautiful, attractive woman—and young. The inevitable lover came upon the scene to console her. They planned to run away together. He was rich. Japan they thought would suit them. Only, by some ill luck, the husband got wind of it and arrived in London just in the nick of time."

"Well rid of her," put in O'Reilly, "I think."

The doctor waited a moment. He sipped his glass. Then his eyes fixed upon his companion's face somewhat sternly.

"Well rid of her, yes," he continued, "only he determined to make that riddance final. He decided to kill her—and her lover. You see, he loved her."

O'Reilly made no comment. In his own country this method with a faithless woman was not unknown. His interest was very concentrated. But he was thinking, too, as he listened, thinking hard.

"He planned the time and place with care," resumed the other in a lower voice, as though he might possibly be overheard. "They met, he knew, in the big house, now closed, the house where he and his young wife had passed such happy years during their prosperity. The plan failed, however, in an important detail; the woman came at the appointed hour, but without her lover. She found death waiting for her; it was a painless death. Then her lover, who was to arrive half an hour later, did not come at all. The door had been left open for him purposely. The house was dark, its rooms shut up, deserted; there was no caretaker even. It was a foggy night—just like this."

"And the other?" asked O'Reilly in a failing voice. "The lover?"

"A man did come in," the doctor went on calmly, "but it was not the lover. It was a stranger."

"A stranger?" the other whispered. "And the surgeon, where was he all the time?"

"Waiting outside to see him enter, concealed in the fog. He saw the man go in. Five minutes later he followed, meaning to complete his vengeance, his act of justice, whatever you like to call it. But the man who had come in was a stranger. He came in by chance—just as you might have done—to shelter from the fog—or—"

O'Reilly, though with a great effort, rose abruptly to his feet. He had an appalling feeling that the man facing him was mad. He had a keen desire to get outside, fog or no fog, to leave this room, to escape from the calm accents of this insistent voice. The effect of the whisky was still in his blood. He felt no lack of confidence. But words came to him with difficulty.

"I think I'd better be pushing off now, Doctor," he said clumsily. "But I feel I must thank you very much for all your kindness and help." He turned and looked hard into the keen eyes facing him. "Your friend," he asked in a whisper, "the surgeon—I hope—I mean, was he ever caught?"

"No," was the grave reply, the doctor standing up in front of him, "he was never caught."

O'Reilly waited a moment before he made another remark.

"Well," he said at length, but in a louder tone than before, "I think—I'm glad." He went to the door without shaking hands.

"You have no hat," mentioned the voice behind him. "If you'll wait a moment I 'll get you one of mine. You need not trouble to return it." And the doctor passed him, going into the hall. There was a sound of tearing paper. O'Reilly left the house a moment later with a hat upon his head, but it was not till he reached the Tube station half an hour afterwards that he realized it was his own.