Secret Agent "X" – The Complete Series, Volume 2

Chapter I

JAWS grim, gaze bleakly intent, a man in a long-bodied roadster drove swiftly toward the rich manufacturing city of Branford. Mysterious, compelling lights of unusual intelligence showed in the depths of his eyes.

Those eyes searched the black river past which the highway wound; searched the road before him, watched the white-painted fence posts that flashed endlessly by. The roar of the smooth-running engine came as a single great organ note, a throaty diapason of power, holding the car at its sixty-mile-an-hour pace. A bend in the river made the lighted windows of Branford visible — pin pricks gleaming in the sable curtain of the night.

The man’s gaze became still more intent. His hands tightened over the wide rim of the wheel.

Staring at those lights ahead he was visioning something else. Above Branford’s roof tops he seemed to glimpse a hovering, sphinxlike presence — the bony-jawed spectre of Death itself with scythe uplifted as a threat and portent of evil to come.

The highway so far had been unnaturally deserted. The man had passed no other cars either going to or coming from Branford. But, as he neared the city limits, an air of grim activity became apparent.

Khaki-clad figures stood in tense groups. Powerful buff-colored autos and police motorcycles lined the road. A harsh voice shouting an abrupt command slowed the approaching roadster.

“Halt! What’s your business, stranger?”

The man behind the roadster’s wheel stared into the alert eyes of a state trooper who stood challengingly, rifle held ready, bayonet fixed.

The stranger fished in a pocket, drew out a paper and presented it to the trooper. It bore the name Doctor Julius Smith, U. S. Public Health Service. The trooper glanced at it sharply, nodded and stepped back.

The car leaped forward with a whine of gears, crossed a bridge, and entered the city proper.

Lights in houses showed plainly now, but the streets themselves were as deserted as the highway had been. Here and there a shadowy figure moved, walking quickly from one door to another, as though fearful of some dread danger. Here and there a head showed behind a closed window, peering out furtively at the roadster speeding down an avenue toward the square.

The state trooper who had admitted the man didn’t know that his credentials were faked. The city itself had no inkling of the identity of this night-riding stranger. The few who stared as he passed penetrated no farther than the surface of his inconspicuous features, little dreaming that those features formed a marvelously clever disguise.

IF they had been told the name this stranger went by in the high Government circles where his activities were followed, they would still have been in the dark. For the man at the wheel was a hidden hunter of criminals, one who inspired terror and wonder along the black alleys of the underworld. A man who had been suspected and hounded by the police themselves on many occasions when his daring methods had brought him into conflict with the law. A man, finally, who was an eternally baffling enigma to the law and the lawless alike — the man called “Secret Agent ‘X.’”

Tonight the citizens of Branford had something far more startling to occupy them than mere curiosity as to the business and identity of a strange man in a roadster. An epidemic of encephalitis, that mysterious form of sleeping sickness more vicious than its African cousin, was raging.

The sinister malady had broken out three weeks before. It had spread from one or two people to dozens and scores of others. A quarantine of martial strictness had been drawn around the city and its suburbs in a frantic effort to check it.

To break through that quarantine line from the inside meant certain arrest and the risk of being shot. All persons entering Branford were questioned and checked with an eagle eye. Once having gone in, they must not get away again. For the sleeping sickness, making of its victims veritable living dead, carried horror with it that was like the crawling touch of icy fingers.

The disease had come upon the city under the most extraordinary circumstances. Nine gorillas had escaped from the experimental department of Drexel Institute in the heart of Branford, where scientists had been using the great apes as living laboratories. The gorillas had been inoculated with encephalitis virus in an attempt to find the cause and cure for this most enigmatic of modern diseases, the germ of which even the finest collodion filters could not isolate.

Then fate had stepped in with a horrible jest. The gorillas had broken loose. Efforts to control a deadly disease had resulted in the worst epidemic of sleeping sickness the country had ever known.

Always a rare malady, there were no more than several hundred cases now. But an aura of horror advanced before the spread of the disease like a ghastly herald of doom. For, in the first period of encephalitis, its victim passes through a stage of facial rigidity in which the features are devoid of all expression — the stage known as the Parkinsonian Mask. Then comes the terrible listless coma from which there is often no awakening.

Secret Agent “X” was aware of all this. Uneasy questions forced themselves upon his mind. What would happen if the malady spread beyond the limits of Branford? What if it reached the teeming, near-by millions of New York? What if it sent octopuslike fingers from there to other great centers of population — Boston, Philadelphia, Chicago, Cleveland, San Francisco, Los Angeles?

The answer came with horrible certainty. Once out of control, the disease would spread as rapidly as the licking flames of a prairie fire. Congested areas would be the focal points of infection. A hundred cases would become a thousand in a week. A thousand would grow to a hundred thousand in a month.

The United States would be visited by a plague as ravaging as those of the Middle Ages, when the mournful bells of the corpse gatherer’s wagons tolled through the midnight streets of London, Paris, Berlin, and Vienna. Worse, the victims of this disease would be living corpses, waiting for the relief of slow death, medical science itself baffled and helpless.

But there was more even than this. The whisper of a hideous suspicion had brought Agent “X” through the quarantine lines to risk death itself. An intimation of something as terrible as the spread of the malady had caused him to wire his intentions to a high official in Washington known in the secret files as “K9.”

For behind the spread of the sleeping sickness Agent “X” had traced the dim outline of a crime pattern almost too startling to be believed.

THE newspapers had stated simply that escaped gorillas had started the epidemic. But Agent “X,” reading and rereading the published facts, had felt uneasy questions growing in his mind. Why was it that the great apes were seen solely at night? Why had only one of them actually been shot? And why was it that Branford’s richest citizens had first been afflicted with the disease?

These items pieced together had nourished the dark suspicion in Agent “X’s” mind. These were the indecipherable riddles that had brought him to Branford in search of answers.

Fear lay like a pall around him in the quiet, deserted streets. He drove his car slowly, eyes glowingly alert. As he approached the city’s main square, a weird illumination whitened the sky ahead.

The shimmering, questing beams of dozens of searchlights mounted on emergency fire and police trucks filled the air. They were probing through the vegetation of the square, playing over tree trunks and branches, reaching along the faces of buildings. Behind the searchlights, grim-eyed men held rifles ready. The hunt for the escaped gorillas was on, as it had been for many nights past.

Explanations of the apes’ mysterious disappearance had been put forward. Some said they had fled to the sewers for hiding. Others said they had found refuge in some deserted building. Still others claimed some madman had given the great beasts harborage.

Yet, wherever they stayed in daylight, they were still appearing unexpectedly at night. And those who met them and were scratched or bitten came down with the dread disease. Not only this; mosquitoes, it was now claimed, inoculated with virus from biting human hosts, were also spreading the malady. Thus the threat grew hourly worse. And it was into this living hell that Agent “X” had voluntarily come.

Here in Branford, following his policy of helping men and women to live in peace and happiness, he was prepared to face what might be the greatest crime riddle of his career. Disguised as Julius Smith of the U. S. Public Health Service he hoped to unearth hitherto unknown facts.

A police car stopped him at the edge of the square. His credentials were looked at again. Then he was allowed to proceed. There were three immediate courses open to him. He could go to the office of Doctor Traub, Branford’s commissioner of health, and present his papers. From Traub he would learn all the latest details. He could go to Drexel Institute and learn the circumstances surrounding the gorillas’ escape. Or he could take part in the search for the gorillas themselves in these first hours of darkness when the apes appeared to be most active. In hiding apparently during the day, it was just after nightfall that they went abroad in quest of food.

It was this that appealed most to Agent “X.” Doctor Traub and the institute could wait. Horror at the invisible invasion of a dread disease, sympathy for the victims, made him crave direct action.

He swung away from the square. The first and only gorilla to be caught had been shot at that spot. It seemed to “X” that the battery of searchlights would keep the others away. A gnawing suspicion in his mind made him seek the section where the city’s rich dwelt.

He drove swiftly along a wide avenue, passing only a few other cars. These were police cruisers, or those of doctors marked with green crosses. The night seemed to hold menace and mystery. The spectre of death still hovered above Branford. A dank miasma of evil seemed to rise from the lawns and grass plots.

Over his face and hands Agent “X” rubbed a special solution which would keep away mosquitoes and night-flying insects.

HE came at last to a street of stately, high-walled mansions. In front of them flowed the river. Beyond, on the opposite shore, burned the campfires of National Guardsmen, stationed there to see that even wealthy citizens of the town did not try to escape. A millionaire’s launch had been surprised and riddled a few nights before, and its owner killed. A trooper caught accepting a five-thousand-dollar bribe to let a wealthy merchant through the quarantine lines had been summarily court-martialed.

Agent “X” parked his car and prowled ahead on foot. The silence and loneliness of the city were more apparent than ever now. Lights showed in the houses ahead, but the citizens had barricaded themselves as for a siege. Windows were closed; many blinds were drawn. Sounds of human habitation were few.

Somewhere a dog barked. “X” could hear the faint voices of the guardsmen across the river. The night air was still. He moved across quiet lawns, still as a wraith, alert as an Indian. In his clothing he carried some of the strange offensive and defensive weapons that had become a part of his equipment. If he saw a gorilla he was prepared.

Twenty minutes passed; a half-hour; three-quarters — and nothing happened. The menacing silence of the night was unbroken by any sound that he could not place. His nerves were on edge. The blood in his veins tingled.

Ahead of him now was the Garwick mansion, a huge yellow brick house of French colonial style, surrounded by wide lawns. Victor Garwick was one of Branford’s leading citizens.

As “X” approached the house, following the secret hunch that had brought him to Branford, there came the sudden sound of a high-pitched human cry.

It was somewhere at the other side of the big house, and it electrified the Agent into swift action. He heard the crashing, rending noise of breaking glass — then that terrible cry again. When he bounded around the building on the velvet-smooth lawn among flower beds and ornamental shrubs, he saw a leaping shadow in the blackness ahead. It was no more than a flashing blur of darkness, blotting out for an instant the glint of the river water.

He gave pursuit, grasping the small gas pistol that was one of his weapons. But the shadow had disappeared. He did not waste time searching. If what he feared had happened, it was more important to get into the house.

LIGHTS were blazing in rear windows now. He heard excited voices, some one moaning hysterically. He ran around to the front door, knocked loudly. When a frightened servant opened it, he heard some one talking excitedly on the telephone.

The servant seemed dazed. He stared at Agent “X” with dark, unseeing eyes. His face was dough-colored.

“I was passing,” said “X.” “I heard a scream. What’s happened? I am Doctor Smith.”

The servant stood humbly, did not answer; but a terrified looking woman came running toward him.

“You are a doctor, you say? Come at once! Something horrible has happened! One of those apes—”

She did not finish. Her voice broke in a frightened sob. Agent “X” strode after her. A big man stood in the room they entered, staring helplessly at a young man who was leaning against a chair, holding his arm. The young man’s face was ashen. He looked at Agent “X” with fear-glazed eyes. The woman seized the big man’s arm.

“A doctor, Victor! Perhaps he can do something. Perhaps it isn’t — too late!”

Victor Garwick spoke quickly to “X,” neglecting even to introduce himself.

“My son was attacked just now! A gorilla broke into the house. If you are a doctor, for God’s sake do something before—”

“My medicine case,” said Agent “X.” “I left it behind me in the car.”

A groan came from Garwick’s lips. The woman spoke tremblingly.

“Doctor Allen will come anyway, Victor—”

“I’ll see what I can do,” said “X.”

The younger man, Victor Garwick’s son apparently, seemed too paralyzed for speech. His father babbled on:

“The ape raised the window. Dave found him here. We scared the beast off — but not before he had bitten Dave!”

“Let me see your arm,” said Agent “X.” His tone was professional. He had studied medicine along with many other sciences. He could do as much as any physician in Branford to check the inroad of encephalitis.

David Garwick rolled up his sleeve and displayed the livid flesh wound on his arm. With a sudden sharp exclamation, “X” drew the boy nearer a bridge lamp. His eyes began to burn with a strangely intent light. He gazed for seconds at the marks on the young man’s arm, then took a small measuring device from his pocket. He bent down, went over the tooth marks with minute scrutiny. Then he straightened abruptly.

He did not betray his sudden, violent excitement to the boy or his parents, but he was tingling. Cleverly simulated as these marks were, they did not fool Agent “X.” Fang marks he had seen many times before. And these were not the abrasions of an animal’s incisors. They were wounds made by some double-pronged injection instrument. They were concrete evidence of the black shadow of crime that he had already guessed at.

Chapter II

“YOU actually saw the gorilla?” Agent “X” asked the boy sharply.

“Yes — and dad saw it, too.” David Garwick glanced toward his father, who nodded swiftly.

Mrs. Garwick touched “X’s” arm, raised worried, appealing eyes.

“What is it?” she demanded. “Why don’t you do something, doctor?”

Agent “X” said quietly, “You say your own doctor is on the way here. It will be better for him to take the case. He undoubtedly knows your son’s constitution — which is an important factor in treating the disease.”

The woman’s fingers tightened on his arm.

“You mean that David will come down with sleeping sickness?”

Her agonized voice touched “X’s” heart. She was a mother — and her only son had come under the shadow of the dread epidemic. His voice was husky as he said:

“Doctors are working now to find a serum. The Public Health Service is at work—”

“At work!” Mrs. Garwick’s eyes blazed. “They had those horrible apes down there — and they let them escape. If my son comes down with the disease — they are to blame!”

Victor Garwick cried harshly, “And I was asked to contribute! I helped them financially! I wish now I hadn’t!”

“The whole city blames the doctors at Drexel for what has happened,” said Mrs. Garwick. “They shouldn’t have let those apes get out!”

Agent “X” did not argue the point. He could not blame the stricken parents for being prejudiced. He turned from them to the boy.

“Do whatever your own doctor says,” he told him. “Keep cheerful and everything will turn out O.K.”

“You think then that I will come down with—”

David Garwick’s quivering lips could not frame the dread word. Agent “X” was silent. His discovery that the disease was being spread, in some cases at least, by injection, drove all doubt from his mind. David Garwick had been inoculated with the germs. His boyish face would before long set in the terrible contours of rigidity — the Parkinsonian Mask.

Two weeks was the usual incubation period; but the germs of this dread epidemic seemed to be unusually virulent. In a matter of days or even hours David Garwick would feel the clutch of those silent microbe invaders, would sink slowly into the horrible listlessness from which he might never be aroused.

Agent “X” was filled with deep, silent fury — fury against the inhuman fiends who were responsible for this.

“You’ll come through all right,” he said huskily. He wished he could feel the confidence he tried to put into his voice. “I’m going directly to the institute,” he said. “I understand they are working night and day there, trying to develop a serum. Your own family doctor will do all that can be done.”

The haggard eyes of the Garwicks followed him. He passed the trembling servant in the hallway, went out into the night. A few hundred feet from the gate a green-crossed car roared past him and into the Garwicks’ drive. Apparently their family doctor had arrived. “X” hoped he would be able to bolster up their morale for the ordeal to come.

HE strode swiftly to his own car, climbed in, and retraced his route back along the avenue. His disguised features were set as he drove through the gloom. Fury had become a white-hot resolve to fight this hideous evil. For a moment, Agent “X” pressed a hand to his side where an old scar, received on a battlefield in France, gave him a momentary twinge of pain. Excitement sometimes made the wound throb as though the piece of shrapnel that had caused it were freshly imbedded.

It seemed the sign and symbol of the Agent’s amazing courage. For the scar had drawn the flesh into the semblance of a crude “X.” Years ago, physicians had predicted that it might cause his death; but his extraordinary vitality and indomitable will had cheated the Grim Reaper. The scar remained as an ever-present reminder of death — but death was no longer feared by Secret Agent “X.” He had come to grips with it too often. His only fear was ever that death might overtake him before his strange hazardous work was done. With horror hovering like a dreadful shadow over a whole great community, the “Man of a Thousand Faces” must fight as never before. And, with death on all sides of him, he must hold death at bay.

He sped down the street toward Drexel Institute. The massive white stone building was set on a slight hill surrounded by spacious grounds. It was a temple of science upon which its founder, Alfred Drexel, had lavished millions until the stock market crash of ’29 had wiped out his fortune.

Now the great building stood in all its grandeur, paradoxically bearing the name of a ruined man. It had sucked up the greatest proportion of Drexel’s wealth and energy. Drexel, still a resident of Branford, had had to sell his own huge estate. He lived in modest apartments in the very shadow of the huge institution he had created.

What an ironic blow that the citizens of Branford had turned bitterly against the very thing that had been their chief cause for civic pride. The words of Mr. and Mrs. Garwick had shown that feeling against the institute ran high. This was proved too by the presence of an extra armed guard of police around the grounds.

They stopped “X” at the gate. His papers were examined before he was allowed to drive in. An armed institute guard asked for his credentials again at the door. Then he was shown into the building and taken to the office of the director, Doctor Gollomb.

A round-faced, shrewd-eyed man, with the high forehead of a scholar, Gollomb gave him a brusque welcome. Worry had deeply lined the director’s face. His fingers kept up a restless tattoo on his desk.

“I’ve had only four hours sleep a night since this epidemic started, Doctor Smith,” he said. “We’re still hoping to find a serum — but with the apes gone it’s damned difficult. What the people don’t understand is that the development of serum therapy requires time and patience. I’m helpless. Not only my apes are gone — but one of my best men has disappeared as well.”

Agent “X” leaned forward. Tense interest brightened his eyes.

“Who is that, doctor?”

“Just a student here — a young man named Hornaday. He’s a strange, moody chap, but close to being a genius. When he worked at all he had the patience of Job. With an ultra-microscope and a filter using polarized light he thought he had isolated the encephalitis germ. We were counting heavily on his findings. He was working on a new kind of serum — a radical method of treatment consisting of bacteriophage that would kill the virus-producing organisms.”

SECRET AGENT “X” started. Doctor Gollomb’s words told him that the student Hornaday had apparently been on the right track.

“How do you account for Hornaday’s disappearance?” he asked suddenly.

Doctor Gollomb leaned forward, tapped “X’s” arm. “He wandered away once before. I’ve said Hornaday was moody. He was the type who would submit to no discipline or restriction. When the wanderlust struck him he would drop everything and go. That’s the simple explanation.”

“You’ve made no mention of this to the police or the public?”

“The police — no! Why should I? I kept it from the papers purposely. They’d be sure to circulate wild stories. I don’t want any more scandal attached to the institute! It’s bad enough as it is!”

Doctor Gollomb paused. A troubled frown wrinkled his forehead. “There’s only one thing that puzzles me,” he continued slowly. “And it is another reason for keeping silent on the question of Hornaday’s — ah — voluntary vacation. He took all his notes and some of his equipment with him!”

“That’s incredible!” snapped the Agent.

“Yes! And if he reads reports of this epidemic and doesn’t come back when we need him so desperately I shall never forgive him,” said Doctor Gollomb. “Brilliant as he is, I’ll see him expelled from the institute!”

The director’s eyes snapped with anger. But Agent “X’s” glowed for a different reason. Drexel’s most brilliant student of encephalitis missing — staying away at a time like this. The Agent shot another question:

“Just when did he leave — before or after the gorillas escaped?”

“About a week before, doctor — but if you’re trying to insinuate anything, it’s preposterous!”

“X” raised a hand. “I’m trying to insinuate nothing. I just wish we could locate Hornaday. He might be most — useful.”

“I agree with you, Smith. But we have other brilliant men here and I’ve sent for Doctor John Vaughton, the English expert on sleeping sickness. If only we had some of the gorillas! Even one would help. I am hoping hourly that a capture will be made. I’ve instructed the health commissioner and the police to do all in their power to bring the animals back alive.”

“Rather a difficult feat,” said “X” dryly, “since the gorillas’ claws and teeth are impregnated with disease germs. It is doubtful if the police will feel as idealistic about it as you scientists.”

“Doctor Traub, our health commissioner, has the welfare of the community at heart,” said Gollomb.

Agent “X” rose. “I’d like to take a look around the institute, Gollomb.”

The director nodded. “I’ll show you over the place myself.”

HE showed “X” the steel cages from which the gorillas had escaped. The explanation of how the animals had got out was simple. One had contrived to break the lock on his door. Naturally imitative, he had opened the doors of the others from the outside as he had seen their attendant do. Then a window had been raised and the band of huge jungle creatures had trooped out into the night.

“A late spring freeze-up had made the ground hard,” explained Gollomb, “but there was no snow. That prevented us from tracking them down.”

Gollomb and “X” visited the bacteriological room with its glittering microscopes, centrifuges, incubators and cultures; the vast chemistry department under the charge of Doctor Ritchie, the Institute’s treasurer. There was a physics department, another devoted to biology.

Agent “X” met the staff, too — or those of them doing night work. These were principally in the departments of medicine, chemistry, and biology, co-operating now in an effort to combat the ghastly epidemic.

It was after nine when the Agent left. He went directly from the institute to city hall to see Doctor Traub, Branford’s health commissioner. But the commissioner was not in his office. A weary-eyed secretary told “X” that he was supervising sanitary precautions in distant parts of the city, and might not be back until midnight. Since the spread of the sleeping sickness he had given up all semblance of regular hours.

As he went down the steps of the city hall to his roadster, “X” decided again to take an active part in the gorilla hunt. It might be three hours before he could see Traub.

His pulses quickened as he slid behind the wheel. He had a dual reason for wanting to capture one of the hairy beasts that menaced Branford.

He must if possible gain concrete proof that the animals were being trained to carry and use an injection device leaving a mark like teeth. His brain hammered at the problem of why such a device should be used, since the beasts’ claws and teeth carried the infection — but that must wait until he had proof that the thing was actually being done. That the apes could be trained to use such an injector was a startling but not utterly fantastic idea.

He must also, somehow, capture one of the animals alive and take it back to the institute. The lack of adequate media for experimentation was crippling the work of those at the institute. Some sort of serum, made from the spinal fluid of one of the apes, on the order of rabies serum, might save hundreds of lives.

“X” guided the powerful roadster through Branford’s business section and headed for the suburbs. He felt he was better fitted than the police to make a live capture. The police were armed with death-dealing automatics, machine and riot guns. “X” had his ingenious gas pistol. At short range it would knock out an ape as well as a man. That was the weapon he intended to use.

His eyes gleamed with excitement as he approached the vicinity of the Garwick mansion again. This open section with its lawns and wooded patches seemed the logical place for the apes to prowl. And he was definitely sure now that the rich of Branford were being preyed upon.

Accident alone had caused the disease to spread to the poorer sections; even the most cunning criminal mind could not control the flights of germ-laden mosquitoes.

He passed other cars filled with men hunting the apes. These he avoided, and parked at last in a dark side street. Unseen, silent, he struck off across the wide lawn of a big house that was tightly shuttered.

“X” slipped a square of black cloth over his face. He remembered that gorillas were supposed to be able to see in the dark. With his gas gun in one hand, a concentrating flashlight in the other, he prowled across many lawns.

Once a night watchman hailed him. Agent “X” retreated swiftly into a clump of shrubbery, half expecting to hear a charge of buckshot whistle by. But he saw the watchman turn and dash into the house. “X” moved quickly on to a section several blocks away.

A moment later two police cars flashed by. They had, “X” assumed, come in response to the watchman’s telephone call. He turned his back to them, continued his own lone way. Fighting single-handed, he had been able to achieve some brilliant results in his warfare on human menaces to society. Tonight he was pitting his trained alertness against the instinctive cunning of animals.

At the rear of a group of rich men’s estates “X” paused and tensed. Had something moved over by the low wall that separated one lawn from another? He strained his eyes. Yes — there it was! An instant’s glimpse of a dark silhouette against the star-studded sky.

He crouched low to the ground to get a better view. The silhouette showed again, an ungainly blob on the top of the wall. Then the Agent’s heart raced. For his straining eyes made out a massive, furry head.

He gripped his gas pistol more tightly, moved forward. The dark blot against the sky had disappeared. Had it gone over the wall? Was it coming stealthily his way? Agent “X” was not sure, but cautiously he moved on.

Close to the wall, at a point fifty feet below the spot where he had seen the moving shadow, he crouched again. Nothing was in sight. No faintest sound broke the peaceful stillness of the night. And yet he was positive he had not been mistaken. Prickles raced along his skin. Alone in the blackness, he was close on the trail of one of the great, germ-spreading apes. Horror was somewhere ahead of him, watching him perhaps, waiting to spring.

He moved catlike along the ground parallel with the wall. He was slowly approaching the spot where he had glimpsed the ominous shape.

He felt certain now that it had been going over the wall when he saw it. Yet he had no proof of that. A windbreak of low evergreens made a dark line twenty feet from the wall. The creature might have slipped into them. The Agent waited, ears attuned to the infinitesimal sounds of night. The creature must not get away. Luck had played into his hands.

Lightly, silently, he placed his feet on the top of the wall, tensed for the spring over. Then grass blades rustled behind him. Out of the blackness, from the direction of the evergreens, a huge furry shape hurtled at him.

The Agent sensed, rather than saw it. But the spruces made a background as black as jet. He raised his gas gun, fired; and knew instantly that his aim had been poor.

For a snarl came from the darkness slightly to his left. And before he could swing the gun again a heavy paw descended on his arm with paralyzing force, and the weapon was knocked from his fingers.

Chapter III

POWERFUL hairy arms enveloped the Agent’s body in a smothering embrace. In that instant he felt himself in the very shadow of death — either instant death at the hands of the great ape, or the slow death of sleeping sickness. For “X” had glimpsed the gleam of metal in the anthropoid’s powerful paw.

His own hand vised over the creature’s wrist, warding off the deadly prongs of the germ-laden injector. The merest scrape of it against him, the merest skin abrasion — and all the knowledge of present-day science could not save him from the slow advance of the encephalitis bacilli. His features, too, would set inexorably in the rigidity of the ghastly Parkinsonian Mask.

The creature’s repulsive breath fanned his face. Dimly he saw the glitter of eyes deep-sunken in its massive, hideous head. “X” lurched sidewise, threw the ape off balance. They crashed to the hard ground in what seemed a death grip.

Would the gorilla, frustrated in the use of the man-made injector, resort to tooth and claw? That possibility made “X” battle with frenzied force. The lives of hundreds, perhaps thousands, were linked up with his lonely struggle against horrible death.

He panted, jerked an arm free, lashed out with clenched fist. The hairy creature grunted, seemed dazed for a moment. Then, with a guttural snarl, it tried to pin Agent “X” to the ground. For a moment, “X” was underneath. For a moment his grasp of the creature’s wrist, the wrist that held that terrible metal injector, weakened.

The hairy coat of this inhuman monster made it hard for “X” to retain his grasp. But he knew a dozen tricks of leverage. He knew how to make use of his own strength and weight. He heaved upward, pushed back, toppled the creature off him, still retaining his grip on its arm.

The Agent’s pulses were hammering. A vivid light glowed in his eyes. There was that in this ape’s actions that puzzled him — caused a dark, incredible suspicion to leap into his mind. But it was no more than a suspicion. There was no proof yet. There could be no proof unless he captured this fighting fury which sought to conquer him.

He tried to get his free fingers around the creature’s throat But the ape struck “X” an agonizing blow in the side with upthrust knee. The full force of it landed on that puckered X-shaped scar close to the Agent’s heart. Pain from the old wound blossomed into life, gripped Agent “X” with paralyzing fingers of quivering agony.

And in that moment, unable to move or breathe, his fingers on the great furred paw relaxed. The thing sprang away into the darkness, raced across the black lawn toward the spruce trees and disappeared behind them.

Panting, the sweat of pain cold on his forehead, “X” rose to his feet. By sheer will power he conquered that wrenching agony in his side. He dropped to hands and knees, groping for his gas gun. He found it, and a moment later his left hand encountered the cold cylinder of his flashlight. But the other thing he sought — the metal, tooth-shaped injection device, which he had hoped the furred monster had dropped, was nowhere to be found.

FOR another hour, grim-eyed, he hunted dark lawns and streets. He had kept the sinister germs of encephalitis from entering his blood, but he had lost in his first real encounter with this mysterious hairy emissary of microbe death.

It seemed that his battle with the furred creature had driven it and the others off for good that night. Agent “X” wished now that he had come armed with a real bullet-shooting gun as well as his gas pistol.

It was after eleven when he got back to the spot where he had parked his car. He drove toward the health commissioner’s office. As he neared, the Agent tensed. The fear-inspired quiet of Branford’s streets was broken now, and in its stead sounded the clamor of an angry mob.

Torches made lurid light along the block. Swarming hundreds had gathered before the city hall. In their midst, a soap-box orator was shouting. Of huge proportion, with an ugly pockmarked face, there was a kind of twisted intelligence in the man’s features. Fanaticism fed the smoldering gleam in his eyes. His voice rose with a harsh note of passion:

“Are we to stand like dumb beasts doing nothing while disease spreads among us and devours our children? These clever ‘priests of science’—what are they? Fools! And you are fools to look to them for help. Who loosed the scourge among us? They did — and they must be punished! But we must be allowed to leave the city before it is too late!”

“X” shouldered his way through the muttering crowd. He strode up the steps of city hall. The voice of the radical fanatic screeched after him.

“Look — there goes another doctor! What good are these medical men in a time of need? They are fools, fools, fools!”

The crowd took up the cry. Jeers and catcalls followed “X.”

A knot of policemen barred his way, nervously watching the angry mob. “X’s” credentials as Doctor Julius Smith admitted him. He found that the commissioner of health had returned. The commissioner was in his office in conference with one of Branford’s harassed physicians, but he granted “X” an immediate interview.

Traub was a ponderously built man of the politician type. Small, shrewd eyes gleamed in his florid face. “X” introduced himself and Traub gestured with a fat hand toward the man beside him.

“This is Doctor Roeber. He’s handling some of the worst cases of sleeping sickness in the town. He was telling me about ’em.”

“X” nodded to Roeber, a forceful-looking man whose manner held reserve and dignity. Traub’s exact opposite in type. Then the Secret Agent looked up and caught the commissioner staring at him in sharp speculation. “X” had a momentary qualm. Traub was no fool. Was it possible he knew there was no Doctor Julius Smith in the Public Health Service? Branford’s commissioner spoke heavily.

“Your credentials, if you don’t mind, doc. In times like these the city is full of fakers. We’ve had to arrest a dozen quacks who risked disease in their efforts to gyp some of our citizens.”

“X” handed the commissioner his papers. Traub studied them, chewing on his unlighted cigar. He nodded, handed the papers back, tipped his cigar ceilingward at a belligerent angle.

“Well, doc — I suppose the Government is going to take a hand and fix things up in a big way.”

There was a thinly veiled sneer in Traub’s voice. He apparently resented outside interference even in this emergency. He thrust a fat finger toward “X.”

“We’re doing everything that can be done now. This thing will have to run its course like other epidemics. Our doctors and health department officials are working day and night. I hope when you go back to Washington you’ll give us credit.”

“X” started to answer, cocked his head and listened. The cries of the mob outside were like the roar of an angry sea as the orator whipped his listeners to an emotional pitch. Agent “X” nodded in the direction of the street.

“How are you going to deal with that?” he asked. “Mob violence can’t be ignored, Traub.”

“Oh, that’s that red, Vronsky,” the commissioner grunted angrily. “He’s a trouble-maker. We tried to arrest him a week ago — and the city employees threatened a general strike if we did. We’ve been forced to combat his crazy speeches with counterpropaganda. I’ve got something to quiet them now.”

The fat commissioner leaned forward, his voice sinking to a confidential whisper. He winked at Doctor Roeber and at Secret Agent “X.”

“You’ve heard of Doctor Vaughton, Smith?”

The Secret Agent nodded. “You mean John Vaughton — the expert on African sleeping sickness?”

“Exactly — and he’s in this country now. Arrived yesterday. He’s due to be in Branford tomorrow. Doc Gollomb of Drexel Institute radioed him. We’re releasing the news through the press right now. It will be spread across the front pages of the early morning editions. That ought to quiet the people.”

“He has a cure then?”

Traub’s eyes became the shrewd eyes of a politician.

“No — but the people think he has. They don’t know the difference between encephalitis and the African disease caused by the bite of the tsetse fly. They think a germ and a trypanosome are one and the same. They didn’t go to medical school like I did and get educated.

“We’ve got to quiet them somehow. We’re letting them think that Doctor Vaughton is a wizard. We’re telling ’em everything will be jake when he arrives. He’ll be met at the station tomorrow with a brass band and everything, like a hero. He’s admitted to Gollomb he don’t think he can do anything for this kind of sleeping sickness — but I wired him to keep still about that. The citizens of this city have got to think he’s a big medicine man. If they don’t we’re gonna have riots and hell to pay.”

Commissioner Traub rose ponderously, waving his cigar. “I can spill some mean oratory myself. Watch me settle those mugs out there right now.”

TRAUB went to the steps of the city hall, and Agent “X” followed, keeping in the background. The commissioner’s big voice boomed commandingly above Vronsky’s hoarse, impassioned shouts. The cries of the mob stilled.

“Go back to your homes, folks,” roared Traub, waving his cigar. “We’ve got a doc lined up now who’ll knock this epidemic for a goal. Vaughton’s his name — the biggest sleeping sickness shark in the world. What he don’t know you could scratch on the back of a postage stamp. He’s coming to Branford tomorrow. He’s got serum with him that will make every germ in this city high-tail for cover!”

Some one in the crowd cheered. Another voice took it up. The tense, fear-strained faces of those in the mob broke into smiles. Here was good news at last. The angry cries of Vronsky, the radical, were drowned out. His fiery words no longer had the power to sway the mob. One by one men left to go to their homes and spread the good word.

“Poor saps!” said the commissioner from his lofty pinnacle of knowledge. He waved Agent “X” back to his office with a satisfied smile.

“X” felt scorn for the man’s tactics. Here was the action of a cheap politician, not the lofty idealism of medicine, which Traub was supposed to uphold. Yet there was some justification for his act Something had to be done to quiet the people. Frenzied mobs and strikes inside the quarantined city would only add to the horror. It was Traub’s manner, rather than his actual hoaxing, that the Agent criticized. Back in the commissioner’s office, “X’s” eyes betrayed some of the contempt he felt. Traub seemed to sense it.

“You high-falutin’ birds from Washington are all right in the laboratory, maybe,” Traub said, “but you don’t know anything about handling folks. Another of you Public Health Service men was here last week— By the way, he didn’t say nothin’ about you coming. How was that?”

The beginnings of suspicion glinted in Traub’s small eyes. “X” answered quietly, though his nerves were taut. Traub, accustomed to associating with shady politicians, was not an easy man to fool.

“I asked permission to come on my own hook,” the Agent said. “The Government is worried about this epidemic. If it should spread elsewhere—”

Traub’s cigar tilted aggressively again. “It won’t! We’re gettin’ rid of the mosquitoes. I got men pouring oil on every pond and puddle in the city limits. The police will locate those escaped apes and put ’em out of business.”

“Some of them should be caught alive and taken back to the institute,” said “X.” “Doctor Gollomb is handicapped by lack of material to work with.”

“Yeah,” jeered Traub. “We’ll put salt on those monkeys’ tails and just lead ’em back on a string. I’ve told Goliomb if he wants the apes alive he can go out and get ’em himself with some of those science sharks of his. My men have got orders to shoot ’em on sight!”

“X” nodded, and rose. He saw that there were warring elements here. Traub on one side. Gollomb on the other. And the angry populace ready to rise up in rebellion. They were all sitting on a powder keg with the constant menace of the terrible disease overshadowing everything.

He went to Branford’s main hotel, checked in as Julius Smith, establishing headquarters where Traub and the institute could reach him. Then he drove blocks away and, under another name, rented a cheap furnished room. Here he deposited his make-up materials and other strange paraphernalia. There was no telling when a quick change of disguise might be necessary.

There were several people he wanted to investigate. Vronsky, the radical agitator, was one. Drexel, founder of the institute, whose fortune had been wiped out, was another. It was the Secret Agent’s policy to pursue every possible angle of investigation until he had a complete picture of a case. He had established to his own satisfaction that there was a human agency behind the spread of the dread disease. Who was it?

Shortly after midnight he returned to his hotel again. A grim-faced deputation met him in the lobby. Traub headed the group. His small eyes smoldered, the stump of a fat cigar projected from his thick lips. Two uniformed men were at his side: another in plain clothes, who had, to “X’s” experienced gaze, the look of a detective.

The Agent’s pulses hammered. A sudden ominous silence had fallen at his entrance. Then Traub spoke with oily ponderousness.

“Let’s see those papers of yours again, doc.”

Agent “X” handed his credentials over, eyes flicking with steely alertness from one to another of the men. Traub passed the papers to the plain-clothes man.

“There you are, chief,” he said with heavy smugness. “They must be forged.” He turned to “X,” his face hard.

“This is Chief Baxter. I telephoned Washington long distance, doc. The jig is up. There ain’t no Julius Smith in the Public Service line-up. You’re just another damned quack — the worst of the lot — and you’ll cool your heels in our jail till the epidemic’s over. Then they’ll ship you to the Federal pen for impersonating a Government employee. Arrest him, chief!”

Chapter IV

GRIMLY the two cops closed in on Secret Agent “X,” guns drawn.

“We got enough trouble,” continued Traub harshly, “without being pestered by frauds like you. I hope you get the sleeping sickness!”

The commissioner touched a match to the stub of his cigar, puffed furiously, then turned his pompous back and strode out.

“Take him down to headquarters, boys,” said Chief Baxter. “There’s a cell waiting.”

For a tense moment the brain of Agent “X” worked desperately. He had underestimated the suspicious nature of Branford’s commissioner of health.

One thing “X” knew — he must not be locked up. His battle against the machinations of unseen criminals must not be stopped. The glow of determination filled his eyes.

One of the cops was going through his pockets. He found the Agent’s gas gun, snarled an oath.

“Heeled, eh? A crook and a lead-slinger, too!”

The cop’s automatic thrust forcefully into “X’s” side. “Any funny business and you’ll get a lead pill yourself,” he blustered. “That’s the kind of medicine a bird like you oughta have.”

They led “X” out to the curb where a police car was waiting. He made his body tremble as though he were overcome with nervousness. With one foot on the police car’s running board he drew a package of cigarettes from his pocket. With shaking fingers he put one to his lips and fished a cigarette lighter from his vest. The cops stood by impatiently.

“Get a move on,” said one. “You’ll have plenty of time to smoke in the jug, along with the other quacks down there.”

“X” pressed the wheel of the lighter with his thumb. But instead of touching the flame to the end of his cigarette, he moved the lighter suddenly in a swift arc. There was a faint hiss. A jet of acrid vapor spurted from a small hole in the lighter’s side. It was concentrated tear gas under pressure — and it went directly into the eyes of the two cops.

One of them made a wild clutch at “X,” pulled the trigger of his automatic. But “X” jerked the man’s hand aside a fraction of an instant before the report sounded. The bullet plowed into the shiny side of the green car.

“X” snatched his own gas gun out of the cop’s pocket. Hurling both policemen away with a sweep of his arms he leaped into the cruiser. The cops, utterly blinded and swearing furiously, made vain attempts to fire in the right direction.

But, with an expert twist of the wheel, Agent “X” swung the car away from the curb and roared down the block. He pressed the gas button till the speedometer needle of the small swift car showed forty — fifty — sixty — and the hotel was blocks behind.

Then somewhere ahead a siren sounded. A telephone call had gone out from the hotel, of course. Already the radio patrol had been warned. “X” switched on the dashboard radio, heard the voice of the police announcer excitedly instructing all cars to be on the lookout for a stolen cruiser driven by a quack doctor named Julius Smith.

Instantly Agent “X” drew up beside the curb. It was the middle of a block where shadows lay black. He leaped out of the cruiser, merged with the shadows. He strode across a wide lawn and paused beside a hedge. There, in the darkness, his quick skillful fingers performed miracles on his face.

The painstaking disguise of Doctor Smith disappeared. From a hidden inner lining of his coat he took various small portable make-up devices: a tube of volatile plastic material which dried on contact with the air, a tube of pigments. There was no time for an elaborate disguise now; but, with so much depending on him, he could not risk being seen as Doctor Smith again tonight.

When he emerged from the shadows and crossed the lawn to the next street, the contours and color of his face had miraculously changed. He was younger now, ruddy-faced. His inconspicuous features would not cause anyone to glance at him a second time.

He moved boldly along the street and, a few minutes later, arrived at his hideout without having been stopped. Using the key provided him by his landlady, he went directly to his furnished room.

He lingered there only long enough to swiftly pack his suitcase. In ten minutes he was on the street again, seeking another hideout in a poorer section of the city. He hired it under a new name, and at last felt secure for the moment. For a short time he paced the floor of the room in deep concentration.

THE exposure of Julius Smith was a blow to his entire plan. It raised serious difficulties. As Doctor Smith he had access to the institute. He could keep abreast of all that went on in Branford. But now his hands were tied unless—

Agent “X’s” preoccupied pacing stopped abruptly as a thought flashed across his mind. His eyes grew piercingly bright. To the Man of a Thousand Faces a daring desperate plan had occurred.

Swiftly he went through his suitcase, placing in the lining of his coat any of the equipment he might conceivably need. Then he went forth into the night again.

He walked without pausing through the silent streets. Once he was stopped by an officer who asked his business. The Agent said he was an employee on the night shift in the power house, and the officer let him pass.

He came at last to a region of railroad yards, factories, and merchandise warehouses. Beyond were the city limits, where grim-faced guardsmen of the quarantine line patrolled. Agent “X” had no definite plans as to how he was going to get through; but get through he must, if the plan he had conceived was to be put into action.

He saw sentries patrolling at the end of every block. Their bayonets gleamed in the light of fires that had been kindled. Lights had been strung up at other points. No one could possibly slip through without being seen. The sentries had been instructed to shoot to kill.

But the street with the string of lights at its end gave “X” his cue. He ducked through an alley, came back along the inside of a board fence. Beyond was the highway. A camp of state troopers and police was strung along for a half mile out of town.

Secret Agent “X” glanced upward, located the wiring on the emergency lights. His eyes gleamed. Two poles had been rigged with wires which passed down to an underground conduit. Pipe covered the wires for a few feet upward from the earth. Beyond that they had only their own insulation. It was a short extension line with an independent fuse.

The Agent took a small pair of nippers from his pocket. They had been useful in his work before. Now the fate of a city, perhaps a country, might hinge upon their effectiveness. He came around the edge of the fence, waited till the patrolling sentinel’s back was turned, and closed the nippers over the wire. There was a groove in the tiny implement, and a needle point set in the jaw of the nippers above. The wire fitted into the groove, and pressure on the handle forced the needle into the strands.

Instantly there was a blue spark, a sizzle of smoke. The overhead lights winked out — and this particular exit from the city was plunged into darkness.

Under cover of the gloom, Agent “X” strode out into the highway. He heard the sentries shout; heard answering cries from the highway guard. An auto’s spotlight came on, but the Agent was on the other side of the highway now.

He was certain that he bore no germs of encephalitis in his blood. The furred creature he had fought had failed to jab the pronged injector into his arm. His own solution had prevented him from being bitten by any marauding, microbe-laden mosquitoes. He could leave Branford with a clear conscience on that score.

But there was a long journey ahead of Secret Agent “X.” He must find some means of locomotion.

Chapter V

CREEPING through the darkness beside the highway, Agent “X” approached the emergency camp of state police. All those still awake had run up the highway to help repair the short-circuited light wire.

A new fuse and some fresh bulbs and the lights would go on again. Unless the small puncture in the wire were discovered there would be no proof that it had not been an accident. “X” had removed the nippers.

His eyes roved quickly. Five trim motorcycles were parked on their metal stands close to some bushes by the road. Four had police insignia on them. The fifth was evidently an extra that had been commandeered for service. It was a speedy two-cylinder Harley-Davidson.

Agent “X” walked up to it, slid it off its stand, kicked the stand up. For a moment he paused. The dark highway led away from the city on a slight decline. To start the popping engine now would bring a swarm of police after him. Even if he outdistanced them, telephone and telegraph messages would flash ahead and he would be stopped. But if he could get away without being seen or heard, the loss of the motorcycle might not be discovered until morning. By that time he would be far away.

Holding the machine’s handlebars, he wheeled it off beside the road. Fifty feet from the police camp he got into the leather seat and coasted silently away into the darkness. The two-wheeled vehicle picked up speed, sliding under its own momentum like a silent wraith on its ballbearings. When the decline ended in a rise he was a half-mile away from the city limits.

But still Agent “X” was cautious. He wheeled the motorcycle up the next hill, coasted again to the bottom, and only then started the engine, careful to keep it muffled.

It bore him away along the dark road with the speed of the wind. The pure night air streaming past his face was exhilarating after his close contact with the germ-laden city. He opened the gas throttle slowly, bent forward over the handlebars and settled down to his long ride. The blood tingled in his veins as he swept forward through the night at fifty miles an hour.

He took the curves like a racer, leaning far over; opened up on level stretches till the two-wheeled machine beneath him became a thundering monster of speed and power.

WHEN dawn came Agent “X” was in New York, his motorcycle parked in a garage. He did not look as though he had spent a sleepless night. Dynamic, unconquerable forces seemed to drive him on. His eyes were bright, his step quick. There was much to be done within the next few hours.

The boat bringing John Vaughton, English authority on sleeping sickness, had docked at twelve the night previous. Vaughton was registered in a New York hotel. All this “X” had learned in messages which had flashed between him and “K 9” in Washington.

The Agent went quickly to one of his New York hideouts. When he came forth again he was well dressed, with the indefinable air of the professional man about him. A card in his wallet bore the name Warner Barrick, M.D., of the New York Academy of Medicine. He went to a garage, took out one of many cars he kept on hand, and drove swiftly to the hotel where Doctor Vaughton was a guest. The famous doctor was just finishing breakfast when “X” arrived. A half-dozen news reporters were interviewing him. In his clipped British accent, Vaughton offered guarded opinions on the current sleeping sickness epidemic in America. He was a white-haired, ruddy-faced Englishman of middle height. Nose glasses added to his impressive dignity. The eyes of Agent “X” noted all this in one swift glance. Then he shouldered forward to Vaughton’s table.

“Good morning, doctor. I’d like a word with you if I may.”

Doctor Vaughton glanced at the card “X” presented, and nodded.

“What is it, sir?”

“Before you leave for Branford there are several physicians of this city who would like your advice on an important matter. Would you be so kind as to come with me to a certain clinic?”

The Englishman looked at his watch. “My train leaves in an hour. There is little time.”

“I know,” agreed Agent “X.” “But all we ask is a few moments.”

Vaughton nodded, got his coat and hat. “X” guided him out of the hotel to his waiting car.

“In the unpleasant event that the epidemic in Branford should spread to this city, doctor, we should like to make certain preparations. We thought that your experience in combating sleeping sickness would make it possible for you to give us advice on precautionary measures.”

Doctor Vaughton shook his head worriedly.

“There is misapprehension in many quarters,” he said. “My work has been against the African variety of the disease — an altogether different malady. I tried to make that clear to Doctor Gollomb, when he radioed me to come. I told him I could do little.”

“You have no serum, then, that would effect a cure?” “X” asked.

Vaughton spread his hands in a helpless gesture. “Serum. No! I am here only in the capacity of investigator and possible adviser.”

“X” nodded. The truth of what Traub had told him was now confirmed. In combating the inroads of encephalitis even the great Doctor Vaughton would be helpless.

“X” was silent until he drew up before an apartment building.

“This way please, doctor,” he said.

Vaughton looked about him curiously.

“Your clinics here in America are located differently from ours in England,” he smiled.

The Secret Agent remained silent as he showed Vaughton to an apartment on the fifth floor. He opened a door, led Vaughton inside. The apartment was empty. It showed no signs of medical equipment.

“What’s this?” asked Vaughton sharply. “Do you call this a clinic?”

“No, doctor,” Agent “X” said softly. “I brought you here under false pretenses. I regret very much that the step was necessary. You will understand later, perhaps.”

“And what do you intend doing?”

“This!” said “X” suddenly.

He drew his gas gun from his pocket and, even before the look of horror on Vaughton’s face had fully materialized, the Secret Agent fired. The jet of harmless gas went into Vaughton’s open mouth and nostrils. The great doctor sank without a groan to the floor.

AGENT “X” quickly locked the door of the apartment — which was one of his secret hideouts. Then for a moment he looked down at the unconscious Englishman, frowning. This was the desperate play he had planned in the dark hours of the night. It was daring. Almost it seemed uncalled for, possibly harmful to the interests of the citizens of Branford. But Agent “X” knew what he was about. Vaughton, student of the malady caused by the bite of the African tsetse fly had admitted that he would be little, if any, help against the dread encephalitis. Agent “X’s” researches had told him this even before he had met the man.

But, disguised as Vaughton, the Man of a Thousand Faces could accomplish something concrete in his battle with the hideous human fiends behind the spread of the disease.

There was less than an hour now before Vaughton’s train would leave. Never before had the Secret Agent worked so rapidly on a masterly disguise. Much depended on this disguise. For a few moments he practiced British speech and characteristic gestures.

Then, with delicate instruments, he made precise measurements of the contours of Vaughton’s face. Satisfied at last, he set a three-sided mirror on the bureau, placed a chair before it and went to work.

First he removed the brief disguise of Warner Barrick. This had been a purely fictitious character which he had assumed only for the purpose of leading Vaughton to the hideout. Then, for a few moments, Secret Agent “X’s” own features were revealed.

He appeared as he really was — as not even his few close intimates ever saw him. The face reflected in the three-sided mirror seemed boyish at first glance. But it was a curiously changeable face. For, as he turned his head, and light fell on it from a new angle, maturity and the record of countless experiences seemed written there. Here was the dauntless courage of a man still youthful, but with wisdom and foresight gained in many strange places of the earth.

His deft fingers began creating the disguise of Vaughton. Carefully chosen pigments imitated the exact color of the Englishman’s skin. The volatile materials which were flexible even when dry built up the contours. A white toupee came next. Then Agent “X” lightened the shade of his irises with an ingenious drug of his own until his eyes were the exact blue of Vaughton’s.

At the end of fifteen minutes it seemed as if Vaughton’s twin brother were in that room. Agent “X” worked still more swiftly now. He changed to Vaughton’s clothing, lifting the papers from his pocket. Then he took a slender hypodermic from a small leather case and injected into the doctor’s arm a harmless narcotic which would keep him unconscious for many hours. He put Vaughton on a sofa, making him comfortable with pillows, and threw a blanket over him, and left the apartment.

Back in Vaughton’s hotel, the clerk hailed him.

“You’d better hurry, doctor, if you want to catch that train. We took the liberty of getting your grips all ready.”

A bell boy with Vaughton’s grip and two suitcases hustled him to the curb. A spinning taxi took him to the railroad terminal. And a moment later, a distinguished, white-haired English gentleman settled himself in a Pullman chair with a sigh of satisfaction. Once again Agent “X” was started on a journey — a journey that would carry him back into the City of Sleeping Death.

Chapter VI

AS the train on which Agent “X” was a passenger pulled slowly out of the New York terminal another passenger, arriving late, leaped aboard. This was a blue-eyed, blonde-haired girl, her small, fine-featured face flushed with excitement.

She carried a suitcase in one hand, a portable typewriter in the other. Masculine eyes followed admiringly as she hurried along the car’s swaying aisle. Her petite figure was delicately proportioned and the curls escaping from beneath her small smart hat gleamed like spun gold. She wore her clothes with an air and she seemed to radiate youth and vitality.

She passed the white-haired, distinguished-looking Englishman and took a seat farther along and on the opposite side of the aisle. As she moved by him the Englishman gave a sudden, visible start.

It was the first time in hours that he had betrayed any emotion. A strange look flashed in the depths of his eyes. He stared with rapt intensity at the piquant profile of the blonde-haired girl. She turned, as though sensing eyes upon her. But her gaze, meeting his, showed not the slightest flicker of recognition.

A faint gleam of humor appeared in the eyes of the white-haired gentleman. Then it vanished, and was followed by a worried frown. What was this girl’s destination? Was it possible that—

For minutes Agent “X” pondered the situation behind the mask of his ruddy-faced disguise. He saw the girl open a magazine and settle down as though for a long trip. When the conductor came down the aisle to take her ticket, he watched carefully.

The blue uniformed official glanced at the bit of pasteboard in his hand and shook his head sharply. His face showed worry as he stooped and spoke rapidly to the girl. Agent “X” could hear a few words.

“No place for you to go — quarantined — better change your mind, miss.”

The girl’s pretty face, as she looked up at the conductor, broke into a sunny smile. Her answer was too low for “X” to hear. But he saw the conductor nod somberly, punch her ticket and stick it beneath the upholstery of the seat in front.

The gleam was bright in the Secret Agent’s eyes now. He waited until the conductor had left the car, then made his way down the aisle to the girl.

“Pardon me miss — your face is familiar.”

The girl looked up with startled incomprehension into the white-haired Englishman’s ruddy face. Her blue eyes studied his features. She shook her curls.

“I’m sorry,” she said. “I don’t think we’ve met. There must be some mistake.”

The man disguised as Doctor Vaughton smiled. He sat down in the other half of the seat and continued speaking with a clipped English accent.

“I am Doctor Vaughton, and I interviewed a lot of newspaper people this morning. I’m on my way to Branford to see about this epidemic of sleeping sickness. I had an idea you were among the reporters at my hotel.”

THE girl gasped. “That’s the strangest thing I’ve ever heard of!” she exclaimed. “I am a newspaper reporter — but I wasn’t at your hotel. The Herald sent a man to see you. I’m going to Branford myself to cover the epidemic.”

“But surely your paper didn’t send you!”

“Not exactly. I — er — volunteered. I’ve got an aunt in Branford. I’m going to stop over with her, and do a feature story while I’m there. The Herald will be glad to get it.”

“But, my dear young lady, do you know the risk you’re running?”

The girl nodded. A determined gleam shone in her blue eyes, and her small pointed chin lifted aggressively.

“I know — and so do the doctors and nurses working there. If they’re not afraid, why should I be? The rest of the country ought to be told just what’s going on in Branford. I want to open everyone’s eyes to the danger. I want to tell them of the courage of men like you, Doctor Vaughton — men who aren’t afraid to fight for the safety of humanity. They wirelessed you on the ship. I heard about it in the Herald office last night.”

Agent “X” spoke softly, “Could nothing persuade you not to go?”

“Nothing!”

The man disguised as Doctor Vaughton spoke strangely then.

“I might have known Betty Dale would go where there was danger — and where she could be of service!”

The girl’s face drained of color. Amazement darkened her eyes as she stared into the face of the man beside her.

“I–I don’t understand! You know my name!”

Secret Agent “X” smiled. His fingers closed momentarily over hers.

“The Man of a Thousand Faces knows more than just your name. He knows that Betty Dale is one girl in a million — with the blood of her fighting father in her veins.”

The effect of his words upon Betty Dale was electric. Her lovely eyes dilated and the fingers holding the magazine in her lap trembled. Then her breath caught. The stranger had extended one finger and made a quick motion on the cover of the magazine. His finger tip had traced the outline of an invisible X.

Color flooded Betty Dale’s pale cheeks then. The conflict in her eyes, where hope had seemed to struggle with disbelief, gave way to a look of sheer happiness.

“I never dreamed!” she whispered. “You — you fooled me again!”

In the instant when the man beside her had revealed himself as Secret Agent “X,” Betty Dale’s glowing blue eyes and the deepened flush of her cheeks had betrayed an emotion she struggled to master.

For, though she had never to her knowledge seen his real face, Betty was one of the few people in the world who knew the details of the Secret Agent’s glamorous, amazing career. She was aware of his strange talents, sensed his dynamic power, and had proof of his courage. He had been a friend of her dead father’s, the father who had been a police captain, slain by gangster bullets. In her heart she scorned and hated criminals with the same intensity that drove Agent “X” again and again into danger against them.

And in her heart she loved this strange man. He made all other men seem tame and ordinary by comparison. That was perhaps why she had not married, why she had rejected a dozen proposals and had chosen to make her own career as a clever, talented newspaper woman — waiting, without quite admitting it to herself, for the time when Agent “X” would finish his battle against crime — and they might be more to one another than mere loyal friends.

In months past, her one thought had been to help him. She had kept her own emotions hidden lest they interfere with his dangerous, desperate work. She hid them now, and spoke composedly.

“Why are you going to Branford? Is there some crime there, also?”

“X” hesitated a moment. Then he spoke in the strange, enigmatic manner he often used.

“If the signs are true, there are wolves as well as apes behind the plague. If the signs are true, crime holds the high card in this game of death.”

Betty Dale’s slender fingers became tightly interlaced.

“You don’t mean — it can’t be—”

Agent “X” nodded. “But it is! Be careful, Betty. Say nothing of this to anyone — and keep your eyes open every instant. You understand?”

“Of course! Oh, how glad I am that I decided to come,” whispered the girl. “Something seemed to tell me— And now perhaps I can be of some help to you—”

She gave him the address of her aunt. He told her she could reach him at the Hotel Regis. Then, assuming again his role of Doctor Vaughton, “X” went back to his own seat as the train rolled on toward the city over which the spectral figure of Death kept ceaseless watch.

AGENT “X” was prepared for the greeting accorded Doctor Vaughton by the citizens of Branford. Otherwise it might have taken his breath away.

As the train pulled into the Branford terminal, he saw the gleaming instruments of a brass band. It was stationed just beyond tight lines of armed police that guarded the station platform to see that no one broke the quarantine by boarding the train. He saw, too, several cars filled with city-officials; and a sea of faces behind them — thousands of Branford’s citizens, eagerly awaiting a sight of the great doctor.

A group of Red Cross workers descended from the train first. They, too, were risking death to help combat the terrible malady, and their appearance was greeted with cheers. Then came Betty Dale, her slight, golden-haired young figure causing a ripple of question and comment among the onlookers. Lastly, Agent “X” in his remarkable disguise stepped to the platform.

At sight of him the cheers rose to a frenzy. The band broke into a lively military march. But, as Agent “X” approached, even the music was drowned out in a wild clamor of voices.

“Vaughton — Vaughton — Vaughton!”

A woman, tears streaming down her face, ran forward to kiss his hand. A man, overcome with emotion, grasped his arm. Doctor Traub’s publicity had taken effect. The people of Branford looked upon Doctor Vaughton as a human savior — a man who would lift the curse of the sleeping sickness from their loved ones.

Pale strained faces about him showed the ravages of fear, of restless nights, of worry. He was heavy-hearted as he looked about him. He was fighting for these people — but not as they believed. If they could pierce his disguise, their cheers would turn to fury. They would fall upon him, rend him limb from limb.

His mind raced as he was conducted through the quarantine lines to one of the official cars. Doctor Traub was there; the mayor of Branford; two of the commissioners. Other commissioners and a group of aldermen made up the retinue.

TRAUB stood up in the tonneau of the open car, pulled Agent “X” to his feet beside him. Traub’s hand was lifted, asking for silence. The band ceased playing. The multitude grew quiet. Traub’s voice boomed out.

“My friends and fellow citizens! We welcome today one who is to perform miracles in our midst. We welcome Doctor John Vaughton — the greatest living authority on sleeping sickness. He’ll have our sick cured in a few weeks, friends. We can rest easy now, knowing that the tide has turned — knowing that the black hordes of disease are about to be driven back by the white light of science.”

It was a pretty speech. The crowd broke into a wild tumult of acclaim. People cheered and wept. Children were raised to shoulders to get a glimpse of the great physician. The mayor shook “X’s” hand, moisture gleaming in his own eyes.

“Speak to them!” he cried. “Brace up their morale, doctor! Tell them you’re going to cure their sick families!”

Taut with the emotion that racked him, Agent “X” lifted his own hand in a gesture for silence. As he spoke into the tense hush that followed, he could not keep the hoarseness from his voice. Incomparable actor that he was, the blind faith of these poor souls affected him.

“I’ll do my best,” he said. “Go to your homes. Be patient. I will work for you body and soul.”

It was all he could say. Traub thumped his back. The mayor wrung his hand again. The people cheered.

When the cars turned toward city hall, the people followed, shouting and rejoicing. But it seemed to Agent “X” that the gaunt spectre of Death leered down sardonically from the skies above.

He was taken into the mayor’s office in the city hall. Traub and the commissioners and aldermen crowded around him.

“I want you to know, doctor,” said the mayor, “that we are all for you. We understand that the epidemic in this city is out of your line. We understand that you’re here partly if not wholly to bolster up the morale of our people; to keep them quiet until headway has been made. We appreciate that, and you’ll have our eternal gratitude for anything you can do.”

Traub spoke after the mayor. “You’ve got to keep on being a propagandist,” he said. “Don’t let the people know that you have any doubts. Let them think you’ve got a serum that will fix them up.”

Agent “X” pondered a moment. A mysterious gleam came into his eyes. A gambler always, he was about to make a gamble now. For a deep motive of his own, he was about to make an assertion that on its face was a falsehood, yet which held in it the elements of truth. He studied each face in the group around him. He spoke in a low, tense voice:

“Gentlemen, let us hope the faith of your citizens in me is not altogether misplaced. I dared not wire ahead for fear I would be misquoted. But I have something almost worked out which will arrest if not cure the disease. Otherwise I would not have come at all.”

Cheers broke the startled silence that followed his words. Traub and the mayor pumped his hand once more. An alderman left to give the word to his family. Another stepped forward to beg Vaughton to visit his own home, where a case of sleeping sickness had developed.

“I’ve got to get my bearing first of all,” said “X.” “I want to try and trace the progress of the disease — to study its particular type and confer with the doctors at the institute.”

“A car and chauffeur are at your disposal, doctor,” said the mayor. “They will be yours while you are here — at your service day and night.”

“Thank you, gentlemen,” said Agent “X.” “If I may have the car at once, I’ll start going over the ground without further delay.”

He was conducted down the steps of city hall to a big black limousine from which a liveried chauffeur sprang with quick deference. “X” directed him to drive to the Regis Hotel. Here he deposited all of Doctor Vaughton’s luggage. It would be safe until, or if, the real Doctor Vaughton arrived.

Back in the car again. Agent “X” gave swift orders through tight lips.

“Drexel Institute first,” he said.

ALL that day Agent “X,” as Doctor Vaughton, gathered facts. Driving up and down the streets of the city, he got the names of each family which had been visited with sleeping sickness. These he noted down carefully in a small book he carried. He was especially careful to record the names of the wealthy, and the dates at which the malady had first broken out. In most cases these coincided. And all of the earlier cases had come as a result of an attack by gorillas.

At dusk he ordered his chauffeur to drive him back to the Hotel Regis. A banquet was to be given in his honor by officials of the city that evening. After it was over, “X” planned to change his disguise and mingle with the city’s poorer population.

Vronsky, the radical agitator, was a character who interested him. The man seemed to hold great power over the city’s labor unions. There was also Branford’s underworld to be explored. Here he might find the roots of the hideous crime plot.

His swift car swept through fast darkening streets. With the approach of night, nearly everyone in Branford retreated to their homes, closed doors and windows, and stayed inside. Fear of the gorillas still held sway.

A bridge over the river at a spot where it cut through the town loomed ahead. The river divided the city in half. Stores and the homes of the wealthy were on one side. On the other were factories and the jumbled crowded homes of workmen and their families. The uniformed chauffeur, aware of the importance of his position as driver for the great Doctor Vaughton, sat stiffly in his seat. The big closed car rumbled out on the bridge. And suddenly the Agent’s eyes focused ahead.

A truck was coming from the opposite end of the bridge. It was a high-bodied vehicle with huge tires and heavy bumpers. It seemed to be approaching at reckless speed. Dust and grime darkening its windshield hid the face of the driver. But Agent “X” tensed as he saw it come plunging on at a swift pace directly down the center of the narrow road.

His chauffeur honked, expecting the truck to give way. But the big vehicle roared on, hogging the middle. Agent “X” shouted a warning. The chauffeur wrenched the wheel, clamped down on the brakes. Tires screamed on the hard macadam. The limousine slewed over toward the concrete railing at the side of the bridge.

Then the left wheel and heavy bumper of the speeding truck struck the car a heavy, jarring blow. Agent “X” caught a brief glimpse of an evil, tense face peering down.

Concrete snapped like brittle glass. The limousine rocked crazily, twisted about, and reared up. Its heavy engine, jammed sidewise by the full weight of the truck, burst through the railing. End over end, its chauffeur crushed behind the wheel, the big car hurtled toward the sluggish black waters of the river below.

Chapter VII

THE catapulting limousine struck the surface of the river with a mighty splash. The water was deep here. The engine’s weight sent the car plunging to the bottom. Agent “X,” half-stunned by the shock of his crash against the car’s side, was fully aware of his peril as cold water gushed in through shattered glass.

Nose first, the limousine had plunged at least thirty feet and buried its hub caps in the river mud. A roar like a thousand waterfalls drummed in the Agent’s ears. Death’s icy fingers were clutching for him greedily. The river water rushing into the car’s front compressed the air in the space above till a giant vise seemed clamped on “X’s” lungs.

Leaning over the back of the front seat, he turned the beam of his pocket flashlight on the chauffeur. A ghastly sight was revealed. The steering gear, snapping in two, had pierced the man’s body. He must have died instantly.

“X” stood up. In the condensed air formed by the tonneau of the limousine his lungs were bursting. He could not tell whether the roar he heard was that made by the swirling black waters of the river or the surging of his own blood. He lashed out with his fist at one of the plate glass windows. His gloved hand, backed by the air pressure behind it, made the glass literally explode outward. Water filled the car and Agent “X” was sucked out and up in a geyser of foam and escaping air.

With powerful strokes of arms and legs he fought to the surface. He was encumbered by a baggy topcoat, but he was still able to swim. His head emerged above the water only long enough to draw in a deep lungful of fresh air. Then he ducked down again. If there were any watchers, they must not see him.

He was certain that this had been a deliberate attack. Some one had attempted the murder of Doctor Vaughton. The vicious maneuver of the heavy truck had given “X” visible and startling proof that he was at grips with some criminal organization.

There could be only one reason for wanting to murder the English doctor. Some one feared that his skill would stem the epidemic. Some one wanted the disease to spread.

As “X” swam swiftly to the bank of the river, his mind made a quick decision. He would let it appear that Vaughton had been killed. If the murderer felt he had succeeded in putting the Englishman out of the way, he would be less on guard.

The Secret Agent emerged momentarily under the shadow of an anchored barge, then swam from there to a group of dark pilings. He crawled cautiously out and plunged into the space between two warehouses.

There he paused, hearing shouts and cries of horror. People in a neighboring tenement must have seen the accident. They were running toward the river, risking the threat of gorillas and marauding mosquitoes. A moment later, a clanging ambulance approached the ramp leading to the bridge.

“X” stripped off his soggy topcoat and stuffed it far under the foundations of one of the warehouses. In the darkness his fingers moved swiftly, skillfully, removing the disguise of Doctor Vaughton. He whipped the white toupee off, stuffed it in his pocket.

HE was no longer an elderly doctor but a brown-haired young man. A few deft touches with makeup material from sealed waterproof tubes and his own appearance was changed. But he was still wet. He kept cautiously to the darkest streets as he went back to the hideout he had established on his previous visit to Branford.

There he quickly changed his dripping clothes for a dry blue serge suit. He still had Doctor Vaughton’s papers and the list of victims of sleeping sickness that he had collected during the afternoon in his role as Vaughton.

He studied the list carefully. He had marked two of the names with asterisks. The answers given him by these two had aroused his curiosity. Agent “X,” a close student of human nature, knew when people were trying to conceal something.

One of the two was Stephen Vorse, a rich merchant whose small daughter was one of the first to contract the dread disease. The child had been in a state of coma for weeks. And yet Stephen Vorse and his wife had not seemed worried. They had not implored the supposed Doctor Vaughton for immediate help, as other distracted parents had done.

Why was this? Had they adjusted themselves to their daughter’s terrible malady — to her almost certain death? Or was there some other reason for their odd manner?

Another of Branford’s wealthier citizens had acted in the same way. Agent “X” in the role of Vaughton had planned to keep a sharp eye on these two families. He had, in fact, intended to return to the Vorse home directly after the banquet, before changing his disguise.

But, as a result of the grim incident of half an hour ago, there would be no banquet in honor of Doctor Vaughton. Agent “X” knew what consternation must now be reigning in the mayor’s home. And he realized heavily that fear would soon have the city in its grip again.

His lean jaw set. He still held an ace in the hole. If necessary, he could give a plausible explanation if it seemed expedient to have Vaughton appear again. His chauffeur had been killed. No one except the murderous driver of the truck could prove that Vaughton had been in the car.

But for the moment Agent “X” meant to let everyone believe that Vaughton had been killed. He had another disguise ready; another role thought out. Before his three-sided mirror he was already building a new make-up.

Transparent strips of adhesive drew the flesh back from his cheeks, giving his face a hatchet-thin appearance. More of his volatile material covered the tape. A gray toupee covered his brown hair. He had become a middle-aged, hawk-faced man. The blue serge suit lent an air of importance and efficiency.

The Agent selected a card from a hidden compartment of his suitcase — a card which certified him as a special representative of the governer. As a doctor of the State Sanitation Department he would steer clear of the suspicious Traub, use his card only to gain entrance to those homes he wished to visit.

He left the hideout and strode quickly down the street two blocks. There he hailed one of the few taxies still cruising the streets with windows closed to keep insects out. He gave the number of Stephen Vorse’s home. Once again the Man of a Thousand Faces was in action.

THE Vorse residence was another huge mansion in Branford’s “Millionaires’ Row,” facing the river and almost directly opposite the state troopers’ camp that guarded the water exit from the town. A trim maid answered the Agent’s ring, and his sharp eyes studied the girl keenly. Her eyes were shining. Her manner was brisk. Here in this home the dread of the sleeping sickness seemed to have lifted.

Mrs. Vorse’s manner when she greeted him in the drawing room of the luxurious home was not that of a mother who fears the death of her child. It was even more buoyant than it had been when “X” had talked to her in the role of Vaughton less than two hours before. Her voice was steady, assured. There was even a sparkle of happiness in her eyes. The Secret Agent tensed with a heightening excitement.

“I am here to investigate for the governor,” he stated. “We are taking a special census of all sleeping sickness victims. Your little girl was one of the first, I believe.”

For a moment the woman hesitated. “Yes I believe she was,” she said at last. “It was dreadful, doctor! Those early stages — when her little face looked like a mask — then the terrible coma—”

“You are more hopeful now. She is better?” “X” shot the question quickly.

Mrs. Vorse dropped her eyes, then smiled and met his gaze frankly. “Much better. Our doctor has been wonderful.”

“I’m glad to hear it! What is your doctor’s name?”

The woman shook her head.

“I’m sorry — he does not want it disclosed just yet. He has a reason.”

Agent “X” sat silent for a moment. He was puzzled. The woman was evading — but her evasions were not those of a person who fears to betray his own guilt. She was under some sort of constraint — a constraint that obviously troubled her.

She cast a startled glance at her visitor as a child’s voice rang out suddenly upstairs. It was the clear, strong voice of a little girl. Not the voice of an invalid — not the blurred mumbling of a patient in the coma of sleeping sickness. Agent “X” spoke quietly:

“You have only one daughter, Mrs. Vorse. That must have been her voice. You have been most fortunate in her recovery!”

“Most,” agreed the woman fervently. “I can never thank enough the man who did this for us.”

Agent “X” rose abruptly.

“I’d like to see your daughter if I may, Mrs. Vorse.”

Tenseness had crept into his tone, and there was a look in his eyes that seemed to intimidate the woman.

“Why, yes — I think so. I–I’ll speak to my husband.”

She left the room, returning almost immediately with Stephen Vorse. He was a large man, and there was no mistaking his good humor. He beamed at “X” and extended a cordial hand. “I understand you wish to see Mary, our daughter,” he aaid. “But I’m sure you will not insist. The child is still convalescing and must not be excited. A strange face—”

He finished the sentence with a gesture that seemed to take for granted the Agent’s understanding of the matter. But the voice of Agent “X” became suddenly as firm as granite.

“I comprehend your feelings, Mr. Vorse. But I’m afraid I must insist. I promise not to excite the child. I’m used to dealing with them — perhaps you forget that I myself am a doctor.”

A panicky note came into Mrs. Vorse’s voice. “But really, doctor, you must be guided by what my husband says. We have had such luck so far—”

With what appeared to be complete callousness Agent “X” walked toward the stairs. Mr. Vorse’s voice, calling after him, was harsh instead of cordial now.

“I tell you, I won’t allow it, sir!”

Agent “X” paused and looked down at them from the first broad landing of the curved staircase.

“Perhaps,” he said slowly, “you have something to conceal?”

THE words seemed to have a quieting effect on the Vorses. They stared uneasily at each other, then followed “X” up the stairway. The child’s voice sounded again, guiding him to a door which he opened. It was a luxurious nursery, and beneath the silken covers of a small bed a little girl was sitting up playing with a set of dolls. Her eyes widened at sight of Agent “X.” He smiled reassuringly.

“The governor of the state wants to congratulate you on getting well, Mary,” he said.

“Oooo — are you the governor?”

“No — but I’m delivering his message. He hopes a lot of other little girls will get well, too.”

As “X” talked to gain the child’s confidence, he was studying her. That she was convalescing was evident. The horrible traces of sleeping sickness had left and her eyes were bright and alert, without a vestige of the fatal drowsiness apparent.

“You must have a good doctor, Mary,” “X” said.

Her parents put their fingers to their lips, but the child spoke quickly.

“He cured me, but I don’t like him. He wears a mask and sticks things in my arm. He won’t talk to me at all.” She turned suddenly to her mother. “Now I’m well, mummy, I won’t have to go out and see him any more, will I?”

The child’s mother was silent.

“X” spoke quickly. “You have to leave the house to meet your doctor?”

“Yes! They wrap me in blankets and take me out at night. And I’m afraid of the dark.”

Agent “X” nodded slowly. “It must be a very funny doctor you have, Mary. I should think they’d bring your medicine here and not make you go out at night.”

“Maybe he knows my mummy wouldn’t like him to stick pins in my arm.”

“It wasn’t a pin, dear,” said Mrs. Vorse. “It was an injection. It drove all the sickness away.”

The Agent patted the child’s hand, then motioned to the parents, who followed him downstairs. There he faced them questioningly.

“I don’t like your high-handed methods, doctor,” said Stephen Vorse. “I think they’re rather uncalled for. But you’ve discovered the truth. We did send Mary away to be cured by a doctor in this city smart enough to have worked out a remedy for sleeping sickness. He has reasons of his own for wanting to keep his name hidden.”

“What are those reasons, Mr. Vorse?”

“He has only a small quantity of serum in his possession. Not enough, I imagine, to deal with the hundreds of cases which have developed. He has restricted himself to the early victims of the disease.”

The Agent’s lips grew suddenly white. He could not hide the fire that burned in his eyes.

“Nothing to get excited about,” said Mr. Vorse. “I promised our doctor not to speak to anyone of this. But you’ve snooped and ferreted it out. His serum is rare, hard to procure. We are rich — and were able to make it worth while for him to cure our daughter.”

“I see,” said the Agent slowly. But the Vorses did not know that what he saw were the completed outlines of a plot too horrible to be believed. These people were unconscious dupes. They did not know that they were victims of one of the most preposterous and ghastly rackets Agent “X” had ever uncovered in his entire career.

“You are sure you don’t know even this doctor’s name?”

“No — he called us on the telephone and said he could cure our little girl. We thought he was a quack at first. But our own doctor seemed unable to do anything. Mary got steadily worse — passed into the coma. We were desperate. When this doctor who would not give us his name called again, we decided to comply with his request. We took Mary out in the car to a spot designated and parked there until another car came by. The doctor’s assistants were in this car. We were fearful when they drove off with her. But they brought her back, and she began to show signs of recovery at once. She had several more treatments, and the coma gradually passed.”

“I see,” said the Agent again. “I’m sorry I seemed impertinent, Vorse. But it is my business to cover the entire field.”

MRS. VORSE laid her hand on his arm as he rose to go. “You will not speak of this to anyone?” she pleaded. “We gave our promise to the doctor whose skill cured our little girl. He says he is using the money we gave him to develop more of the wonderful serum.”

“I shall not speak of it,” said “X,” “unless—”

He stopped abruptly, and all three heads turned. From the street outside had come a sudden wave of sound. It was a babble of voices, shrill with excitement. They grew louder and louder. Then steps sounded on the front veranda of the house and the doorbell rang violently.

The Vorses’ maid ran to the door. They heard her protesting, arguing with some one. Another voice, gruff and truculent, rose over her own. She gave a little cry. There were footsteps in the hall, and a figure suddenly appeared in the doorway. It was that of Vronsky, the radical. He held his cap in his hand, but his broad, ugly face was aggressive.

“Sorry to intrude,” he said in a tone which made an insult of the apology. “I came here to find out if it was true that your daughter has been cured.”

The maid turned frightened, imploring eyes toward the Vorses.

“Mrs. Vorse,” she cried. “I didn’t mean to! But when Mary began to get better — I–I mentioned it to Fred, a friend of mine. He must have told this man—”

“Then it is true!” rasped Vronsky. “If you have money — the doctors can cure you!”

His eyes blazed with fanatical light. Mr. Vorse made an attempt to quiet him.

“Mary is not well yet — only better. Our doctor is working now to perfect a treatment that will cure everyone.”

But Vronsky had turned and was striding to the door. Agent “X” followed. There was a tense mob of men and women outside.

“The rich can be cured!” shrieked Vronsky. “But the poor cannot! Our Government is betraying us. Doctor Vaughton is here in Branford, and he is betraying us, too! He is tending to the rich and neglecting the poor. We will take Doctor Vaughton prisoner and hold him hostage until our demands for fair treatment have been met. He is at Drexel Institute now. We will go there!”

Chapter VIII

A THUNDERING chorus from the mob answered Vronsky’s impassioned speech. A woman leaped up on the steps beside him, gesturing wildly.

“Vronsky is right! If Doctor Vaughton can cure the rich, he can cure the poor! Why should we stand for such wicked discrimination! We must demand—”

Vronsky brushed the woman aside and drowned her out with his great voice, lashing the crowd to a frenzy with his oratory.

“The institute is guarded, but we outnumber the guards. If Vaughton refuses to come out, we will burn him out! We’ll burn the place down and drive him out — along with the other medical rats in there!”

Agent “X” turned back into the house and sprang past the white-faced Vorses to a telephone.

“Police headquarters — and hurry!”

If these people destroyed the institute they would be destroying their main hope. Sooner or later the expert knowledge of the staff would produce results. The priceless scientific equipment of the institute would be needed. The institute must not be destroyed.

When the voice of Chief Baxter answered, “X” spoke quickly:

“A mob is headed for the institute! They are violent — worked up to a fever pitch of destruction. Send police reserves at once. Strengthen all guards!”

“Who is this speaking?”

“A representative of the governor.”

Agent “X” slammed up the receiver. In his questioning of the Vorses he had unearthed the ghastly motive behind the crime plot in Branford. Greed — incredible, devouring greed, lay behind it; the awful greed of men willing to inflict agony and death in order that they might reap a golden harvest from human fear. The identity of the criminals behind it was still veiled in black mystery. But the present emergency must be dealt with before anything else.

Agent “X” plunged out the door. The crowd was surging down the street now. He ran after it, mingled in the fringes of the mob. The faces of its members were weird and barbaric in the glow of flickering torches improvised from oil-soaked rags wound around broomsticks and fence pickets. They were, he guessed, as much to drive away the escaped gorillas and to smoke out mosquitoes as to give light.

Vronsky headed the mob, turning from time to time to harangue those behind him. Someone broke into a wild, rhythmic song. The crowd took it up, marching to the time of it. Agent “X” did not blame these people. His sympathies were with them. They were desperate. But they were inflamed beyond the reach of reason. No words could persuade them that they were on the wrong track.

The mob swelled its ranks with recruits that ran out to join it. The news had spread like wildfire that favoritism was being shown in Branford — that Doctor Vaughton had attended to the rich and ignored the poor. News of Vaughton’s supposed murder was still being withheld by the police.

Agent “X” left the throng. He dashed down a side street and taxied to the institute. There his credentials took him past police guards and into the presence of Chief Baxter, who had already arrived.

“I’m the man who phoned the warning,” said “X.” “The mob is on the way. But there are women among them. Instruct your men not to fire. There must be no bloodshed. Use tear gas to dispel them if there is no other way.”

Baxter nodded grimly. “I’ll have five hundred men here before the mob arrives. They’ll never break through.”

Police sirens were wailing from all sides. Every instant another police cruiser arrived, disgorging one or more bluecoats. The shrill clanging of a bell, the shrieking of a siren louder than all the rest, announced the arrival of an emergency squad truck carrying a dozen cops.

Agent “X,” the compelling ring of authority in his voice, gave another order.

“Park the police cruisers around the square nose to nose as a barricade!”

CHIEF BAXTER nodded again. As he barked the order, the voice of the oncoming mob could be heard. It was a whisper of sound at first; hundreds of shouting voices far off. It swelled in volume like the slow approach of a storm wind sweeping across the sea. It echoed and re-echoed along Branford’s dark streets. Heads appeared at windows. Some, catching the excitement, poured out to join it, risking the night-flying mosquitoes. It was an hysterical outburst, the violent expression of the city’s long pent-up fears. Many joined the crowd without knowing what its objective was.

Thousands poured into the square around Drexel Institute. Searchlights mounted on emergency trucks were turned on and swept the scene. The lavender beams sprayed light on a wild sea of faces. Vronsky, the fiery radical, mounted a box. The crowd ceased its shouts and cries to listen to their leader. His voice echoed across the square and reached those on the steps of Drexel Institute.

“We want Doctor Vaughton! We demand that he come with us! We demand that he treat our families as he has already treated the rich!”

Police Chief Baxter stepped forward with desperate determination. But his voice was hoarse, and his eyes bright with fear.

“Doctor Vaughton is not here!” he shouted. “Doctor Vaughton has been killed!”

A hush like the dead silence of a tomb followed his words. Then angry murmurs arose. A woman gave an hysterical sob. Vronsky spoke again, harshly.

“A lie!” he screamed. “You are feeding us lies again! You are trying to hide him for your own selfish interests. He has sold himself to the rich!”

Chief Baxter shouted fiercely for silence. “It is the truth!” he cried. “You must listen! He was killed tonight. His car was crowded off the West Bridge in an accident! They are pulling it out of the river now. Go back to your homes and wait. Try to be patient! We must all be patient. No favoritism is being shown. Our doctors are tending rich and poor alike. Other specialists are coming in from outside. We will have the epidemic in hand shortly.”

A sound like a snarl came from Vronsky’s throat.

“The doctors have blundered at every step. What spread the disease in the first place? The institute! We are here to see that no more germs come out of it. Burn the place down, my friends! Burn the institute!”

VRONSKY was versed in mob psychology. He knew that what his followers wanted was violence. Any reasoning, no matter how warped, was good enough for them so long as it led to action. And Vronsky was drunk with his own power. He threw up his hands as the mob roared its acclaim. Women began to creep back. Men edged forward. Those with torches raised them aloft.

“Burn the institute! Burn the pest-house!”

Chief Baxter spoke again, his desperate voice faint amid the uproar.

“Stand back! We have guns and tear gas! By God, we’ll turn them both loose on you if you move another step!”

The cops tightened their grim lines, holding nightsticks and tear gas bombs ready. They had guns, too, but had been instructed not to use them except as a last resort. They were willing to obey. Many had friends among the mob.

But the enraged, milling mass was like a blind beast now, surging forward with but one desire — the desire to destroy — to express its fear by rending, tearing, and burning. They were aflame with resentment against the institute.

Agent “X” watched with taut alertness, eyes brilliant. If the building were fired, the staff might be killed, murdered if they tried to escape. He had seen mobs before.

Now it was surging forward in a yelling, jostling mass. Those with torches were pushed to the front. Cries of “Burn the institute” rose into a mighty dirge.

Chief Baxter barked an order. The foremost police lines hurled their tear gas bombs. They fell among the leaders of the mob, exploded and let loose their stinging vapor.

Coughing, choking, shrieking curses, those at the front of the on-rushing tide of crazed humanity clutched at their eyes. The more timid tried blindly to turn back. But they were pushed forward by their comrades from behind. All the tear gas in the possession of the police could not stem this human flood.

The police began swinging night-sticks. The lead-packed wood cracked on heads and arms. But the police wielding them were manhandled, the sticks wrenched from their hands.

Chief Baxter shouted to the second line of police entrenched behind the barricade of cars. The cops leveled their revolvers, menacing the mob.

But even the threat of lead had no effect. Shots fired above the heads of the crowd were answered by armed members of the mob. A policeman went down, a bullet in his shoulder. The acrid stench of powder in the nostrils of the besiegers was like a red flag waved before an angry bull. They went berserk.

The barrier of police cars was being pulled aside and rolled away. The top was torn off a car. Men swarmed over it, shouting wildly. In another moment there would be bloody war added to the horror of the plague-ridden city.

Agent “X” sprang into action. Mounting the steps of the institute he faced the crowd, took a deep breath and made his voice as powerful as he could. He flung up an arm and pointed dramatically off across the institute grounds to where dense evergreens made a dark line.

“The apes!” he howled. “The apes are coming! They have been scared out!”

For seconds his words made no impression. He repeated his shouted warning. A few in the crowd heard and realized what he was saying. They stopped in their tracks, yelled to their comrades. Tear gas and the threat of bullets had not stopped the charge. But the menace of the horror-inspiring apes chilled their blood. The foremost men of the crowd echoed “X’s” cry.

“The apes!” they shouted in horror. “The apes!”

Instantly the tide was turned. Frenzied cries of fury changed to roars of fear. Dread of the germ-laden anthropoids amounted to superstitious horror.

People at the rear of the crowd began to slink away. They suddenly wanted to get back to their safe homes, out of the darkness and terror of the night. But fear is as catching as anger.

THE front ranks of the mob not only stopped their charge but began violently pushing back. The angry charge toward the white-pillared facade of the institute turned into a mad stampede away from it. Men pushed, swore, jostled one another in their terrified flight. Vronsky roared that this was only a ruse to disperse them. But they had no ears for Vronsky now. He was thrust off his soap box and tumbled to the street. He had to fight desperately to keep from being trampled on.

Even the police had now taken up the cry, and with fear-blanched faces were following the crowd. Baxter, who had mounted the steps at “X’s” first words, stared at him uncertainly. “X” spoke hoarsely.

“It was the only way, chief — but I’m afraid some of them are going to be trampled.”

The fear-ridden mass of humanity was like a flood now — a roaring, undulating rapids. The square began to empty as quickly as it had filled. It had taken only a sudden change of mood to break the spell of Vronsky’s words.

Agent “X’s” blazing eyes surveyed the scene. He had saved the institute and possibly the lives of those within it. But his fears were grounded. Dozens of people were being trampled by fear-crazed men and women who had no thought of anything except to escape from the claws and teeth of the apes they imagined at their heels.

“Call ambulances!” said “X.” “Quickly, chief!”

The Agent himself rushed down off the steps of the institute and made his way through the barrier of parked and partly wrecked police cruisers. There were people limping painfully after the retreating throng. Others lay writhing, unable to rise from the pavement.

On the edges of the almost deserted square a few cops lingered. They were some of the younger men of the force and seemed to have had the courage to resist the impulse to flee. But their eyes still held fear as they turned toward the institute grounds.

With a sharp command, Agent “X” motioned them to him, and enlisted their aid in moving the injured to safety. The bells of ambulances were clanging in the streets now.

“X” went on toward the outer edges of the square, stepping over debris left by the brief battle — night-sticks, discarded torches and clubs, and a litter of broken glass and stones.

Then suddenly he gave a hoarse exclamation and leaped forward toward a dark heap on the pavement. A ray of light had caught the glint of bright blonde hair, and a terrible realization seared the Agent’s mind. He stooped and lifted the slight figure of a girl in his arms — and looked down into the white, unconscious face of Betty Dale.

Chapter IX

FOR an instant fear laid its cold hands on Secret Agent “X.” The weight of the girl in his arms was no more leaden than the weight in his own heart. He spoke hoarsely.

“Betty! Betty!”

But she didn’t answer. Her golden head drooped pathetically, her body remained limp. With expert deftness the Agent’s tense fingers searched to see whether any bones had been broken; whether the mad, fear-crazed mob had trampled her underfoot. But Betty seemed unharmed. He decided that she had only fainted in the smothering crush of the stampeding crowd.

Then he remembered that she was staying with an aunt in Branford. He quickly summoned a taxi and gave the address. Holding Betty on his lap, her blonde head resting against his shoulder, he urged the taxi to speed. With his free hand he took something from his pocket — a small vial with a screw cap. He opened it, put the bottle to Betty’s lips, and forced her to swallow a few drops of a special concentrated restorative that he always carried with him.

A minute passed as the cab raced through dark streets. Then Betty Dale’s eyes opened. Color began to flood back into her pale cheeks. She moved her arms, cried out, still mentally fighting the mob, mistaking the jouncing taxi for the surge of frenzied people about her.

Agent “X” spoke soothingly, gripping her shoulder tightly.

“It’s all right, Betty!”

The sound of her own name brought her back to full consciousness. Her blue eyes lifted to the face of Secret Agent “X.” She became aware suddenly that a man held her in his arms. The glow in her cheeks deepened.

“Who are you?” she gasped. “Where am I?”

The Agent’s present disguise was as strange to her as the other he had worn. But the look of deep understanding and intensity in his gaze, the fact that he had called her by name, made her gasp again.

“You’re not — you can’t be—”

“Yes, Betty — Agent ‘X’ speaking.”

She clung to him for an instant in a way that made his own heart beat faster; made him conscious of the beauty, loyalty, and intelligence of this girl.

“I heard that Doctor Vaughton had been killed in an auto accident. I was frightened — desperately frightened — for you—”

“If it had been an accident, I might have been killed. But it wasn’t an accident, Betty. It was deliberate.”

He helped her gently to her own side of the seat. Her eyes were wide with horror.

“You mean some one tried to murder you?”

“Yes. What I suspected is true, Betty. There are human fiends behind this epidemic. The people of Branford don’t know it — but they are fighting more than germs.”

“But why did that mob want to burn the institute? I saw them rushing at it with flaming torches before I fainted. They were like wild beasts!”

“They were infuriated because they had heard that Dr. Vaughton was treating the rich and neglecting the poor. They thought he was at the institute and were trying to force him to come out. They didn’t harm the institute though. They were frightened off at the last minute.”

He did not tell her that it was his own clever ruse that had saved the day. Agent “X” never boasted. Betty Dale laid a hand on his.

“Tell me what it all means,” she pleaded. “I can’t understand. How could any human beings, no matter how low, do such a thing as — spread disease?”

“It’s an extortion scheme, Betty. The cleverest and the worst I’ve ever heard of.”

“Extortion! You mean— But what good does it do to infect people with sleeping sickness?”

“The criminals who have the apes apparently have a curative serum as well. They can charge for curing their victims. Only the rich of Branford were deliberately inoculated. The others who caught sleeping sickness were infected by mosquitoes. That is something the criminals hadn’t counted on. But they seem callous to it.”

“I thought encephalitis was incurable!”

The Agent’s eyes blazed with intensity as he answered.

“In the light of modern science it is, Betty. That is the horror of it. Medicine is powerless to aid the victims of the criminals. But whoever is behind this has a curative serum. They are charging thousands to effect cures — and Branford’s rich are meeting their demands.”

“But where does the serum come from?”

“No one knows, Betty — but a man named Hornaday, one of Drexel’s most brilliant workers, has disappeared along with all his notes and papers. It is barely possible that this man is the fiend behind it all — or—”

Agent “X” became silent. He had outlined the crime to Betty, given her insight into the horror that lay like a black pall over the city of Branford, but he was not yet ready to put forward any theories.

She sat forward, clenching her small hands. Her eyes were bright as steel. Her breath came quickly.

“It’s the most ghastly thing I ever heard of! Hundreds of people condemned to a living death so that some fiend or fiends can grow rich. I understand now just why you’re here. Can’t I help you? Can’t I do something?”

Betty Dale’s hand gripped his. Her eyes held tense appeal. But the Agent shook his head.

“There’s nothing you can do now, Betty. If I need you I’ll call. Just keep silent about everything I’ve told you — and keep your eyes and ears open.”

“I’ve wealthy cousins in Branford, too,” she said suddenly. “My aunt’s sister’s people, the Channings. Paula Channing puts on airs. I never liked her very well. But still she’s my cousin. Do you think they ought to be warned? I was going there tonight.”

THE Agent thought gravely for a moment. “I think not,” he said finally. “If they have been marked by the criminals, warning them won’t do any good. And they might spread rumors that would be bad all around. I’m following a lead, Betty. In a few hours or days I hope to—”

The Agent did not reveal to Betty Dale the angle along which he hoped to strike at the hideous extortionists. He left her at her aunt’s with the promise that he would call on her if she could be of any help.

Then he directed the taxi driver to take him to the Garwick mansion. He sat back tensely smoking a cigarette as the cab lurched forward. After the battle at the institute, the citizens of Branford had returned to their homes like frightened rabbits to their burrows. The streets were abnormally deserted, empty even of patrolling police, who had been called to attempt to quell the riot, and had not yet returned to their regular beats. Horror had won out tonight. The spirit of horror appeared to be in complete control of the city.

The taxi lurched into a drive, slid up to the white-columned yellow brick front of the stately Garwick residence. Agent “X” leaped out. Another car was standing before the house, a car bearing the green crosses of a doctor.

A pale-faced servant opened the door. Fear showed in the man’s eyes. His skin was drawn with it.

He ushered the Secret Agent into the presence of three tense-faced people — Mr. and Mrs. Garwick and Dr. Roeber. The woman’s hand gripped the physician’s arm. Agent “X” caught low pleading words.

“Is there nothing that can be done, doctor — nothing at all?”

The servant announced “X,” and Mrs. Garwick turned to him. Her eyes held no glimmering of recognition. “X” was a different man than the one who had come to her on the night of the ape’s attack. His hatchet face, gray hair, and alert eyes were impressive.

“I am Doctor Preston of the State Sanitation Department,” he said, “investigating personally for the governor. They tell me your son was attacked.”

Mrs. Garwick bowed her head miserably.

“Attacked, yes! And now he has contracted the disease. He is already unable to talk — he—”

Her husband stepped forward to lay a protective hand on her arm. Doctor Roeber stood by dejectedly, with an air of helplessness.

“You will allow me to see the patient?” questioned Agent “X.”

Garwick nodded, with the pathetic eagerness of a despairing man who clutches at any straw of hope.

“Yes! You go with him, Doctor Roeber. Tell him about the case.”

Following the family physician, “X” ascended a staircase to the sick room. One of the servants was there, acting as nurse. Her face was almost as pale as the starched white dress she wore.

“X” felt a wave of horror sweep over him as he stared into David Garwick’s face. The boy’s features were set in the first stage of encephalitis — the dread Parkinsonian Mask. It was as though Death had already claimed him and was drawing him relentlessly into that terrible deep pit of sleep from which there is no awakening. Breathing heavily, the boy stared at the ceiling with eyes vacant of all human expression.

FOR seconds Secret Agent “X” gazed at him, pity and revolt warring in his heart. Then he drew Roeber into the hall, and fixed him with burning eyes. Fierce hatred of the criminals behind this thing made his lips white. But he kept his voice steady.

“It seems to be a severe case, doctor.”

Roeber nodded somberly.

“It is. The boy’s heart isn’t good. He has always been more or less an invalid. I have done all I can.”

Roeber started down the hall toward the stairs. But Agent “X” stepped back into the room and bent over David Garwick. A gleam came into his eyes as he noted the boy’s color, his labored respiration, and shallow, flickering pulse. If he knew anything about the disease, David Garwick was rapidly approaching a crisis.

When he returned to the living room, Mrs. Garwick confronted him eagerly.

“What are these rumors that the Vorse child has been cured?” she demanded. She looked swiftly from Agent “X” to Roeber and back to “X” again. Roeber spoke flatly.

“Sometimes they get better. There is still hope for your son.”

“I am asking because we received a phone call tonight,” continued Mrs. Garwick. “Some one claimed he could cure our boy.”

The Secret Agent’s pulse quickened. This was what he had hoped for! The hideous criminals had made their second move — had gotten in touch with the family of their victim.

Mr. Garwick spoke harshly.

“I told you, Stella, that man was a quack! He was too mysterious — refused to give even his name. I don’t trust him. The city is filled with quacks. They are opportunists who would use this time to make money.”

“What do you think, Doctor Roeber?” Mrs. Garwick’s eyes held appeal.

Roeber’s reply wasn’t hopeful. He shrugged. “I don’t know. I cannot say. We medical practitioners seem to be helpless against encephalitis. It is true that the little Vorse girl has been recovering, but who can say what caused it?”

“Then you don’t think I ought to have called in this man?”

“Of course not!” said her husband harshly. “If our own doctors can do nothing, why should we put any faith in a stranger who will not even give his name?”

Roeber shrugged again, turned toward the door. “Keep me informed of the patient’s condition. I will do all I can. Try not to worry.”

Agent “X,” in his role of Preston, lingered after the other had gone. A notebook was in his hand. He appeared to be what he claimed, a representative of the governor. He spoke with sudden urgent authority.

“This phone call, Mr. Garwick — tell me all about it!”

“It was from a quack, I say — and an unscrupulous one, too. I wouldn’t dicker with him. He made some preposterous claim that for a large sum of money he could cure David. I do not believe it.”

“I wanted him to try it,” said his wife. “I am ready to try anything — spend any amount of money.”

“So am I,” said Garwick hoarsely. “It isn’t money that’s stopping me. But I won’t risk David’s one chance of recovery by placing him in the hands of some fraud. The boy’s heart is weak!”

“Yes!” gasped Mrs. Garwick with terror in her eyes. “Even the shock of being attacked by that terrible ape was almost enough to—”

AGENT “X” spoke emphatically. “It will sound strange,” he said, “coming from a doctor. But I believe you made a mistake, Mr. Garwick. Remedies are sometimes found in strange places. This man who called may have a genuine cure.”

Mrs. Garwick’s eyes brightened. “That is what I said! Oh Victor, let’s—”

Her husband looked troubled. “You mean to say you think I should have agreed to his proposal?”

“X” studied the man intently. He wanted to speak freely — wanted to warn these people of what threatened them and the whole of Branford. But they were on the verge of hysteria — in a horror of uneasiness at the mere thought of entrusting their son to a stranger whose very mysteriousness made him seem sinister. If they knew the actual viciousness of the people with whom they must deal they would be certain to refuse to go through with it.

And go through with it they must. Not only to save the frail spark of life in their stricken son, but because now was the chance to get into actual contact with the extortionists. If they arranged for the delivery of David, Agent “X” could wait and follow. His voice became more emphatic, quietly reassuring.

“Doctors try everything in treating a dangerous disease, Mr. Garwick. You must be ready to try anything. If this man telephones again, take my advice and accept his proposal. Do not ask questions. Pay whatever he demands.”

He seemed finally to have convinced them. Mr. Garwick nodded.

“If you recommend it, doctor, I will.”

“Suppose he doesn’t call again!” exclaimed his wife fearfully.

“I think he will,” “X” replied grimly. He kept the excitement from his voice as he went on. “If this man has a special cure, he may ask for complete secrecy. Agree to all demands and keep whatever promises you make — with one exception. You must let me know. As a representative of the governor I will be in a position to advise you on every point.”

Garwick reached out and grasped the Agent’s hand.

“I’ll do that. Just let me know where you can be reached. I’ll feel safer anyway if there’s some one in authority backing me up. Thank you for your advice, sir. I feel encouraged, now that there is some definite course of action to take.”

Mrs. Garwick’s white face lighted in an eager smile. “Perhaps it will be the solution to everything! Perhaps in a few days we will have David on the way to recovery, Victor!”

The smile faded from her face suddenly as a hoarse, frightened voice sounded, calling:

“Mrs. Garwick! Mrs. Garwick!”

Agent “X” turned a startled glance toward the stairs.

The nurse who had been with David stood on the upper landing, her face as white as death. She descended slowly, clutching the railing with trembling hands. At the bottom she stood motionless, seeming unable to speak. Mrs. Garwick rushed forward and shook the servant frantically by the shoulders.

“What is it, Kate? What’s happened? Is David worse? Tell me instantly!”

The servant groped for words, clumsily trying to soften the terrible news she had to convey.

“I just looked at him a minute ago, mum. You know David’s heart’s always been bad — ever since he was a little feller, Mrs. Garwick, and now he’s—”

“You mean — you don’t mean—”

The servant nodded in dumb agony — and Mrs. Garwick, with a piercing scream, sank fainting to the floor.

Chapter X

AGENT “X,” watching this tableau, felt his heart almost cease to beat. The death of David Garwick, itself a tragedy, meant double tragedy for him. Just when hope of trailing the criminals seemed closest, just when he had begun to feel he might be able to wrest the suffering city from the grip of this menace, hope was dashed from his hand.

Kate, the servant, bent over Mrs. Garwick, tears streaming from her worn old face. Mr. Garwick turned wildly to “X.” His face was gray.

“You’re a doctor! Maybe Kate’s wrong! Come!”

He turned and bounded up the stairs. “X” followed. But a brief examination of David Garwick showed that the old servant had been right. The young man’s still features showed the marble whiteness of death. There was no pulse. Under the stress of the shock he had received and the ravaging germs of the sleeping sickness, his weak heart had ceased to function.

Garwick was quiet for seconds, his face contorted, his head bowed in the terrible silent grief of a strong man. Then slowly he raised the covers over his dead son’s face.

“I most notify Roeber,” he said dully. “A doctor is no longer needed.”

It was then that Agent “X” spoke, his own voice low and tense.

His fingers clutched Victor Garwick’s arm.

“Don’t call anyone, Mr. Garwick! Wait until you’ve heard what I’ve got to say — and prepare to be profoundly shocked.”

Garwick’s dazed eyes looked into his without any comprehension.

“What is this you’re saying?” asked the stricken man. “You can tell me nothing that will interest me now.”

“X’s” fingers tightened on the man’s arm. “Pull yourself together, Garwick! Other lives may depend upon your doing so. Listen to me! The death of your son was not a natural one. Your son was murdered!”

Victor Garwick seemed to realize slowly what the Agent was saying. He stepped back, groping for the edge of the bed upon which his son’s body lay.

“What madness is this? What are you talking about?” he demanded.

“Just what I said,” snapped the Agent. “David was murdered by human beings who have the cruelty of fiends.”

“Good God, doctor — are you trying to drive me mad? Didn’t he come down with sleeping sickness? Isn’t there an epidemic raging? And didn’t the disease and the shock of the ape’s attack stop his heart?”

“True!” said “X.” “That is all true, Garwick. But hasn’t it ever occurred to you that some things about this epidemic are strange? No — I can see that it hasn’t! The cunning of the criminals has fooled you as it has others, and as it was meant to.

“But I’m telling you now. I am telling you that your son was purposely inoculated with the germs of encephalitis. That he is a victim of one of the most evil extortion rackets I have ever come in contact with.”

“Then why didn’t you warn me when you first came? Why aren’t you calling the police now? Supposing I tell you that I don’t believe a word you say?”

“X” spoke more harshly still. He seemed to tower over Victor Garwick, and he was gazing into the man’s eyes with that strangely compelling look of his, filled with the blazing domination of a powerful will.

“You’ve got to believe me! Listen! Stephen Vorse’s little girl has been cured. And how? By this person you thought was a quack. He called the Vorses, too. They met his demands. He sent his assistants to get the girl. She was taken out of the house in an automobile, treated several times — and she has recovered. The man who telephoned was no quack. He was a member of the criminal ring behind this. He could have cured your son David if the boy’s heart had not been weak. That was why I advised you to follow his instructions if he called again.”

“But you said nothing about all this!”

“No! Would you have let David be placed in his hands if I had? I knew your reactions might jeopardize the boy’s life and put the criminals on their guard. So I advised you without explaining the motives behind it. I wanted to save your son and if possible capture the criminals.”

“And now — it is too late,” said Victor Garwick brokenly.

THE Secret Agent’s eyes seemed to gleam like polished steel. His low-spoken words were vibrant. “Too late to save the boy — yes. But not too late perhaps to trace these fiends!”

He stared at Victor Garwick for seconds. The man shook his head.

“I don’t know what you mean. David is dead. If I sent for them now, they would become suspicious at once.”

“Mr. Garwick,” said “X,” “are you willing to help me catch those who killed your son? Are you willing to aid in sending these fiends to prison or the chair?”

Victor Garwick swore harshly and clenched his fists. “If these incredible things you say are true — if my boy was really inoculated — I’ll devote the rest of my life to running down the criminals who did it. Come — we’ll call the police at once!”

Agent “X” held the man with detaining fingers. “You still don’t understand,” he said. “These are no ordinary crooks with whom we are dealing. They are fiends so clever that they’ve been able to hoodwink a whole city. The police cannot cope with them. And, once warned that the law is on their trail, they will escape!”

“What do you advise, then?”

“Follow my instructions. I know what I’m about.”

“You are not a doctor? You are a state detective?”

“It makes no difference what I am. I came to Branford to investigate this thing. Certain odd facts which had escaped others interested me.”

Victor Garwick frowned. “If the police cannot cope with the criminals — how can we hope to catch them? What is your suggestion?”

“This,” said “X” tensely. “The man you thought was a quack must be summoned. He must not know that David is dead. His demands must be met. His price must be paid.”

Victor Garwick sharply withdrew his arm and recoiled away from Agent “X.” A fierce look sprang into his eyes — a look of deep suspicion.

“I — see!” he barked. “You yourself have a motive! You stand to make something out of this! What if I tell you I think you are one of the criminals? You know too much! You want me to pay thousands of dollars to a crook who can do my son no good!”

The Secret Agent’s laugh was short and bitter. “Your suspicion is natural, Garwick. I admit that. But here is concrete proof that I am not trying to get your money. Here’s proof that I am as anxious to catch these fiends as you are.”

“X” reached inside his coat, to a deep inner pocket. He drew out a wallet bulging with bank notes. From it he drew a sheaf of bills, dozens of them, of startlingly high denomination.

“Whatever this man charges,” he said, “whether it’s a thousand, five thousand, ten thousand, or more — I will pay it. Money means nothing to me if I can bring these fiends to justice.”

Victor Garwick stared at the money, then studied the Agent’s determined face. He drew a long breath, and his tense attitude relaxed. A man of affairs, used to dealing in the hard facts of life, this offer was the last thing needed to convince him of the Agent’s integrity.

“I’m sorry, doctor,” he said. “Whoever you really are, whatever your motive, I’m with you. And you can keep your money. It is my son who has — been murdered. All I want to do is help you in any way I can.”

Garwick grasped the Agent’s hand and wrung it. Then he shook his head with a puzzled frown.

“But I don’t understand how you expect to outwit these men by getting them to treat David! They’ll see at once that he is dead!”

Agent “X” spoke rapidly.

“I’ll make my plan clear, Garwick. Wait here a moment.”

“X” hurried downstairs. He had to make sure that no one in the house let news of David Garwick’s death reach the outside world.

Mrs. Garwick was lying on the couch in the living room still unconscious. The servants were bending over her. Agent “X” stopped a maid in the act of reaching for a phone. “Not now!” he said sternly. “I’ll take care of Mrs. Garwick. There is good news. David is not dead. It was only a heart attack!”

The nurse who had reported his death gave a cry of thankfulness. The others burst into excited exclamations. This lie was necessary to keep the news of the young man’s death a secret. It was the only way for “X” to carry out the strange plan he had in mind. He went back upstairs quickly and resumed his talk with the boy’s father.

“The man who phoned must be summoned at once — tonight!” he said. “Before the death of your son is known.”

“How?” gasped Victor Garwick.

“By radio,” snapped “X.” Thorough in everything he did, Agent “X” had investigated Garwick’s social and financial connections together with those of Branford’s other leading citizens. “You are a director on the Branford Broadcasting Company, Garwick. An order from you would clear the air so that a message could be sent out instantly, would it not?”

GARWICK nodded. “Yes, that is true,” he said. “But you said you wanted to keep this thing under cover. Any message we send out will reach everyone in town.”

“Exactly!” agreed the Agent. “But we will word the message so that only the criminals will know what it means.”

Quickly the Agent took out a pencil. “Your telephone number, Garwick?”

“River Hill 5407.”

Agent “X’s” penciled moved swiftly over a piece of paper.

“Will the man who called River Hill 5407 call again at once,” he wrote. “Circumstances have rendered change of decision necessary. Vitally important.”

He handed the note to Garwick, and said swiftly:

“Not even the servants must learn of this — unless we can possibly take the nurse into our confidence. The others must think David is still alive. Call the broadcasting station. Get them to put that message on the air at once. If it does not bring results, we’ll have it repeated.”

Anxious now to do anything that would bring the killers of his son to justice, Victor Garwick sprang to a telephone. Agent “X” closed and locked the door of David’s room, then followed the boy’s father. He spoke to a male servant.

“Help me get Mrs. Garwick upstairs at once. I can treat her better there.”

While the master of the house was telephoning his strange order to the broadcasting station, they carried his wife upstairs. Agent “X” dismissed the man who had helped him, then called the old servant, Kate, to his side. A shrewd judge of character, he eyed the woman long and earnestly. She returned his intent gaze without wavering.

“Why do you do nothing for Mrs. Garwick?” she asked the Agent. “I must get back to my patient. Thank God he is all right. But they’ll never forgive me for giving them such a scare.”

Agent “X” laid his hand on the old woman’s arm.

“David is dead,” he said slowly. “You must know the truth. But there is a reason why the others must not know. You’ve been with the boy for years — seen him grow up. You’ve loved him. He was murdered, Kate — I can’t tell you all about it now. But we’re going to try to catch those who killed him. Our success depends on how well you keep our confidence. If you want to see the devils who murdered David brought to justice, go in and stay with him. Guard his door and say nothing of this to a living soul.”

The woman crossed herself. Tears tolled down her wrinkled cheeks.

“I’ll not breathe a word of it. I’ll stay with him, sir, as I did when he was alive, so help me!”

She turned and walked slowly away. Agent “X” knew that he could trust her.

He took out his small vial of restorative fluid and applied it to Mrs. Garwick’s lips. She was on the point of returning consciousness when her husband came slowly back up the stairs. Agent “X” left him to tell her the truth about her son — to explain why they must co-operate with “Doctor Preston.”

He went down the stairway again and turned on the huge radio that stood in the drawing room.

At first, soft-toned jazz issued from it. Then suddenly the music stopped and the announcer’s voice sounded.

“We are interrupting the program for a few moments, friends, to deliver an unusual message. Here it is: ‘Will the man who called River Hill 5407 call again at once. Circumstances have rendered change of decision necessary. Vitally important’.”

Several times the announcer’s precise voice repeated the message. The Secret Agent listened tensely. He knew the message was being heard all over the city of Branford. Wherever there were radios — in homes, restaurants, clubs, places of amusement — people were pausing to listen and wonder at those strange words. Would it, he wondered, reach the ears of the criminals for whom it was intended?

Chapter XI

JAZZ poured from the radio once more. Agent “X” quickly turned it off. He ascended the stairs and knocked at the Garwicks’ door. His battle with the spreaders of the sleeping death had begun. But there were strange details yet to be worked out.

Mr. Garwick admitted him to the room where his wife was sitting on a chaise longue, her face drawn and pale. The manner of both parents of the dead boy showed that they were ready to place complete confidence in Secret Agent “X.”

“Doctor Preston,” said Garwick, “I’ve told my wife everything you told me. She is just as anxious as I am that these murderers be caught.”

“I’ve just heard our call broadcasted,” said “X.” “Unless I am mistaken we won’t have to wait long for results.”

“Suppose the man does call,” said Garwick. “What will you tell him? When his assistants get David, they’ll realize at once that they’ve been tricked. We might conceivably catch them, but the real heads of this crime ring will get away.”

Agent “X” nodded slowly. Garwick, he could see, had a shrewd analytical brain.

“You’re going to be amazed and perhaps skeptical of my plan,” he said softly. “I intend to pose as your son and let the criminals take me away instead.”

“Good God!” Garwick’s exclamation was one of sheer astonishment. “Why, man, you can’t possibly succeed! The criminals must have seen a dozen pictures of my son. His picture has often appeared in the social columns of the Branford papers. You can’t fool them. They’ll only kill you and escape.”

The Secret Agent held up his hand. “I ask you to have faith in me, Mr. Garwick. I know something about disguise. I’m going to gamble that the criminals will think I’m your son.”

“You mean that you’re going to make up as David?” Mrs. Garwick’s voice held a quaver of amazement and disbelief. Her face had grown a shade whiter, too, and “X” sensed that this would mean an added ordeal for her. He spoke gently:

“It’s the only way, Mrs. Garwick.”

“You’ll never succeed!”

Victor Garwick was pacing the floor nervously now, clenching and unclenching his hands. Agent “X” was tense. He couldn’t tell these people about himself; couldn’t reveal that the face they thought was his own was an elaborate disguise. That would shatter the belief in him that he had managed to create.

“Let’s go downstairs,” he said. “When this man calls, Mr. Garwick, I want you to let me answer him. The thing is too close to you. Your emotion might give you away. Let me make whatever arrangements are necessary.”

“But supposing,” said Garwick, “this man is some one who knows me — some one who would recognize my voice! A strange voice answering for me would cause suspicion at once and wreck all our plans.”

Agent “X” faced the two. There was a strange gleam in his eyes. His lips moved. “This is Victor Garwick speaking,” he said. “Yes, I sent out the radio broadcast tonight. I am willing to consider your offer now. My son is—”

Mrs. Garwick gasped and clutched her husband’s arm. She stared at Agent “X” with baffled wonder in her eyes. Mr. Garwick seemed speechless with amazement, then said slowly:

“I see! You have a most remarkable power of mimicry, Doctor Preston!”

The Agent eyed the man closely, to see if there was any hint of suspicion in Garwick’s gaze. He was relieved to find there nothing but admiration.

“If I hadn’t seen his lips move,” said Mrs. Garwick, “I should have been certain it was you speaking, Victor. I didn’t believe such things were possible.” She turned away. “You go downstairs with the doctor so you’ll be near the telephone. I–I’m going to stay with David for a while.”

As Mr. Garwick descended the stairs with the Agent, his manner held a respect that was almost awe. It was as though the trick of mimicry had given him new insight into this strange man’s character. He sensed that there were depths of mystery and power behind the calm face of Doctor Preston.

IN the drawing room, Agent “X” paced up and down. Would or would not the criminals answer the broadcast? They must have a radio. News of the epidemic had been sent out from time to time. It was almost certain they would want to use every possible means of keeping in touch with all that was going on in Branford.

He glanced at his watch. It was after ten now. The hours since his car had been run off the bridge had been filled with excitement. The hours of the night that still remained promised to be even more strenuous. If his plan succeeded, he would before long establish contact with the cleverest band of criminals he had ever run into.

The shrill ringing of the telephone cut through his thoughts like the thrust of a sword. He stiffened and met the stare of Victor Garwick, who rose, his face paling.

A maid crossed the hall and entered the telephone closet. She came to the door of the drawing room.

“Some one wishes to speak to you, Mr. Garwick.”

“Who is it?”

“He will not give his name.”

“Very well, Estelle.”

When the maid had left Victor Garwick turned to the Agent and gestured mutely for him to take the call. The Agent nodded. Silently he crossed the hallway and entered the telephone closet. He closed the door behind him, picked up the receiver, and his lips framed the words.

“This is Victor Garwick speaking. Who is it?”

There was a moment of complete silence; then a strange voice sounded. To the Agent’s expert ears the pitch showed plainly that it was disguised.

“This is the man who called you before,” said the voice. “I have heard your broadcast, Mr. Garwick. I am listening.”

Agent “X” made his own disguised voice quaver. “For God’s sake, come at the earliest possible moment. I’m ready to try anything. David is getting worse. His heart is weak. If you have a cure — I am ready to try it.”

A chuckle sounded at the other end of the wire. It was mirthless, unsympathetic.

“I anticipated that you might reconsider, Garwick. Your change of mind comes sooner than I had expected, but your son’s condition accounts for that.”

“Hurry,” said “X.” “I assure you I will co-operate.”

“That is well!” said the cold voice. There was a relentless calculation in it that chilled the Secret Agent’s blood. “You understand that absolute secrecy must be maintained. I have only a small amount of my cure left. Feeling is running high in Branford tonight. If it should be suspected that I possessed a cure, I would be attacked and robbed before I could reach you. Furthermore, the charge will be high—”

“That doesn’t matter!” exclaimed “X” in the broken accents of a stricken father who thinks only of his sick son. “I will pay what you ask.”

“It must be cash,” continued the guarded voice. “The charge for the first treatment will be ten thousand dollars. Can you have that amount available by midnight — at which time you and your son will meet us?”

“Yes, yes!” said the Agent hoarsely. “Do you guarantee a cure?”

“That is a foregone conclusion,” said the strange voice. “I am a man of honor. It was I who treated the Vorse girl. You must have heard that she is recovering. I have treated others. They, too, are now on the road to health again. My cure is infallible. That is why my price is high. You agree to my terms of cash and secrecy?”

“I agree!”

“THAT is well. You would not want to jeopardize your son’s life, would you, Mr. Garwick?”

The Secret Agent felt a wave of loathing sweep over him.

“No, of course not,” he said.

“Then have him ready at midnight. Put warm clothing on him so that he can be taken out. Get your chauffeur to help carry him to your car. Then drive slowly along River Boulevard.

“Have your headlights on, but dimmed. See that the left parking light is out, the other lighted. If my assistants have not met you by the time you reach the end of the Boulevard, turn and come back again.

“When they meet you they will flash their lights three times. You will then stop. One of them will open the door of your car and give your son the first hypodermic injection of curative serum. You will give him the payment, and drive on after he has gone. In a few days I will call you and arrange for the next treatment. That is all. Is everything quite clear?”

“Quite!”

The receiver at the other end clicked up. Agent “X” backed slowly out of the telephone closet. For the first time in his career, his hands were trembling with excitement. The cunning of these criminals amazed him. They were using the methods of the most expert kidnapers. They were taking no chances. Like silent, evil vultures, they were feeding on the fear of the city, working with smooth efficiency.

Victor Garwick’s eyes were alert and questioning as the Secret Agent returned to the drawing room.

“Well?” he asked sharply.

“It is settled,” said the Agent. “I have spoken with one of the criminals. You and I are to meet them according to their directions at midnight.”

He outlined the arrangements to Garwick, and added a warning.

“You will have to play your part, too — or everything will fail. They will be watchful. Your manner must not betray the facts in any way that will arouse their suspicions.”

“Couldn’t we arrange to have a squad of detectives following them — ready to nab them?”

AGENT “X” shook his head sternly. “No. That is just what they have taken precautions against. They will trail us. If our car is not alone — if they have the slightest suspicion of anything such as you suggest, they will not even make contact. Only strategy can succeed in this. They must be put off their guard.”

“You are going to attempt to capture them single-handed?”

“No. These men we will see will be only the assistants of the real brains. My only hope is to follow them — and learn what I can.”

The Agent looked at his watch again.

“Ten-thirty. I’ve got an hour and a half to prepare. Good-by, Mr. Garwick. I’ll be back shortly.”

Secret Agent “X” left the Garwick home and sped swiftly to the hideout he had established in the city. There he collected his make-up materials and returned to the Garwick home. Everything depended on the perfection of his disguise tonight — and it was a disguise that must go more than skin deep. He must appear to be a man desperately ill with sleeping sickness. For this reason, he had selected one of several drugs and slipped that into his pocket also.

Back in the Garwick home, his work of make-up began. He took careful measurements of David Garwick’s face as the young man lay still and silent on the bed. Then, with the door closed, he set up his mirrors, took out his strange materials, and his long, sensitive fingers roved over his own features.

The face of Doctor Preston disappeared. For a few seconds Agent “X” appeared as he really was. Then, with the volatile plastic materials, he duplicated the face of David Garwick.

Five minutes later the room harbored a gruesome, uncanny sight. Two young men, twins having exactly the same appearance, seemed to be there. But one was dead, and one alive.

Agent “X” went to the door and called softly to Mr. Garwick. He knew the man was in for a shock, and he wanted to make it as gentle as possible. He dimmed the lights in the room.

“I have made my preparations,” he said, his back turned to the older man. Then he slowly turned, facing the other. Pallor spread over Garwick’s face as he gazed into what appeared to be the face of his dead son. He swayed a little, leaned against the wall for support. His breath came hoarsely.

“My God — it isn’t possible! I— Doctor Preston, you amaze me!” Garwick licked dry lips, glancing from the bed where his own son lay to the man who had so faithfully simulated the boy’s appearance that the effect was almost brutally startling. “We mustn’t let Stella see this! I know it would unnerve her.”

“You are right,” said “X” gently. “Keep her in her room until we have gone.”

GARWICK continued to stare at the features of Agent “X” as though he were seeing a ghost.

“Remember,” warned “X.” “I am supposed to be a sick man. I’m going to wrap blankets around myself now. Then I shall take a small dose of a drug to slow down my pulse and respiration in case they examine me.”

He drew his wallet out and produced ten thousand dollars in large bills. He handed it to Garwick.

“The man I talked to demanded a first payment in cash. I’m sure you haven’t this amount on hand. Give it to the man who injects the serum into me.”

“Very well,” said Garwick. “But I shall insist on reimbursing you later for this. I want it to be my donation to the cause.” He pocketed the bills, and “X” spoke again.

“It is now twenty minutes to twelve. Does your chauffeur know which room David is in?”

“No.”

“Good. I shall go into a vacant room on this floor and lie on the bed. You and he will have to carry me down to the car. There will probably be a spy watching outside the house. Everything must appear right — and let your chauffeur think I am really David. Call him now. Tell him to dim the headlights, and to take out the bulb in the left parking light. The other must be on.

“We are to drive slowly along River Boulevard until a car approaches and flashes its lights three times. If we don’t pass it the first time, we are to turn and retrace our course. Is that clear?”

“Clear. And what will you do after we have been stopped?”

“That,” said “X” softly, “will depend on the circumstances.”

Victor Garwick descended the stairs after showing the Agent to an empty guest room down the hall from David’s room. In a few moments there was the sound of a car coming up from the garage. It turned into the driveway and stopped with running motor before the front steps of the mansion.

Agent “X” lay down on the bed and pulled the covers over him. When Garwick and the chauffeur came into the room, he lay still, his eyes almost closed. The drug he had taken made him feel slightly dizzy, but he was acutely aware of all that was happening.

He saw the scared look on the chauffeur’s face. “X” had already wrapped himself up in blankets to conceal his street clothes. Garwick and the man added others, swathing him securely. Then they lifted him and the Agent made his body rigid. They carried him down to the waiting car and deposited him in the tonneau. “Go to River Boulevard. Drive slowly up it,” said Victor Garwick to the mystified chauffeur. “Stop when I tell you to, and obey any direction I may give you instantly.”

The car turned slowly out of the drive into the road, its one parking light goggling lopsidedly. Apparently unconscious in the back of the car, the Secret Agent’s heart was beating with elation and excitement. At last he was getting somewhere. At last he felt he was on a trail that would lead definitely to the man he sought.

Chapter XII

GARWICK and the chauffeur were silent as the car rolled into River Boulevard. Secret Agent “X” leaned back in the seat, his eyes still half closed. The drug he had taken had cut his pulse down so low that if a doctor had been there to take it, he would have pronounced the Agent a very sick man. But all his faculties were alert, both mental and physical!

From time to time, Victor Garwick’s gaze swivelled toward Agent “X.” The look of awe was still there. Garwick seemed to find it hard to credit his own senses, even now — this man looked so exactly like his dead son.

The car rolled on at a steady pace. On their left flowed the river, gleaming blackly in the faint light of the stars. “X” saw the lights of the state troopers’ camp on the opposite bank. A grim, faint smile twitched at his lips. He pictured the consternation that would fill the camp with turmoil if they could know of the drama taking place on the dark boulevard almost within range of their vision.

His eyes probed ahead between narrowed lids, watching for the first glimpse of the criminal’s car. A police patrol cruiser came around a bend in the road, shot by and out of sight without slackening speed. A half-mile farther along a large closed car passed. It held three men — a driver up front, and two in the seat behind.

The Secret Agent’s keen eyes had caught the intent stare of the men in that car. Without doubt, these were the emissaries of the master mind.

They passed no other vehicle as they traveled the length of the Boulevard. At the end, they turned and came back. In another fifteen minutes Agent “X” saw the closed car approaching them from the opposite direction.

Almost as he spotted it, its headlights winked three times.

“Stop!” Garwick’s voice rang out sharply to his chauffeur. “Draw up beside the road.”

The millionaire’s whole body was taut. His arm, resting against the Agent’s, trembled perceptibly. “X” grasped the man’s wrist firmly to steady him, and to show Garwick that he was still alert and master of himself.

The muffled engine of the car throbbed softly in the stillness as it stopped at the roadside. It was a spot between the widely strung lights on the Boulevard, and darkly deserted. The other car drew up opposite among the shadows. Its door opened. A figure jumped out.

Agent “X” watched tensely through eyes that seemed closed in the stupor of sleeping sickness. He saw a man in a long overcoat approaching. There was a small black case in the man’s hand. The faint glow of the car’s tail-light revealed that he wore a mask. It was a ghostly white mask of the kind used by surgeons to cover the lower part of the face when in the operating room.

The stranger came close and laid a hand on the door of Garwick’s car, wrenched it suddenly open. His voice came low and gruff through the folds of the white mask.

“Your name?”

“Victor Garwick.”

“You have the fee?”

“Yes.”

The man held out his hand. For an instant, Garwick hesitated. “X” realized that he was recalling the instructions he had given him to hand over the fee after the hypodermic injection had been made. He nudged the millionaire with a slight pressure of his arm. Garwick at once placed the roll of high denomination bank notes in the palm of the stranger.

The masked man pocketed the money after a swift inspection of it. This callous member of the extortionist band was evidently taking no chances on not getting his money. Only after he had stowed the bills safely away did he open the small black case he carried.

He withdrew a small hypodermic syringe and unscrewed the cap. Agent “X,” watching with hawklike attention, noted at once that the man’s movements were clumsy. Here was no expert surgeon or doctor trained in the use of scientific instruments. This was an uneducated layman carrying out an order that had been given him.

The man reached forward and lifted Agent “X’s” arm.

“Roll up the patient’s sleeve,” he ordered gruffly.

VICTOR GARWICK complied, while the chauffeur, half turning in his seat, looked on in amazement. When the Agent’s arm had been bared from wrist to elbow the man holding the syringe flashed on a tiny light. He felt awkwardly for the Agent’s pulse, held it a moment, and seemed satisfied. He then inserted the point of the hypo needle close to a large vein and pressed the plunger home.

It was not done very dexterously. The most unskilled nurse could have done better. But the serum contained in the reservoir of the needle entered the Agent’s blood stream.

And now for the first time he asked himself what its effect might be. He was not a sleeping sickness victim. Was it possible that the serum would bring on a mild attack of the dread disease?

The sharp jab of the needle made a stabbing pain in his arm. He didn’t wonder that the little Vorse girl had complained and been frightened.

The man turned away and without another word strode back to the waiting car, slamming the door of Garwick’s car behind him.

At that instant Agent “X” moved with an abruptness that made Victor Garwick gasp. As the door on the left of the car closed — the door toward the other motionless vehicle from which the masked man had come — Agent “X” wrenched open the right-hand door. He kicked off the blankets that swathed him and sprang out into the darkness. He hissed a low, sharp order to the astonished chauffeur.

“Drive on! At once!”

He crouched between the curb and the right-hand wheels of the Garwick limousine as it rolled away. His dark clothing, his collar drawn up about his face, made him indistinguishable in the deep shadows.

The man who applied the hypo needle got into his own car. Agent “X” crept across the roadway. Low to the ground, his body seemed to blend with the black asphalt of the boulevard. He was like a huge quick-moving spider. Just as the strange car began to roll, the Agent’s steely fingers grasped the spare tire on the rear. He swung up his legs, hugged his body close. He was an uninvited passenger as the car lurched ahead.

Those inside were utterly oblivious of what had happened. Once a face peered out the back window. But Agent “X” was crouched too low to be visible.

Seconds passed. The car rumbled on. Then the Secret Agent reached into his coat pocket and drew out a device that looked like a small portable camera.

HOLDING himself tightly with one arm hooked through the tire case, he opened the camera-like object. It wasn’t a camera, but one of the smallest, most delicate amplifying devices in existence. Often before it had served the Agent well. But never had it been put to more important use than now.

He drew from its center a small disc with a black cord attached. This was a tiny microphone. There were two cylindrical dry cells in the box of the amplifier, placed in a corresponding position to roll films. The inside of the cameralike thing itself was the earphone.

Agent “X” placed the whole instrument to the side of his head and, with the hand that was hooked through the tire, he pressed the disc microphone on its black cord against the metal back of the car.

At first only the crashing rumble of the vehicle, magnified to the thunder of a Niagara, reached his ear. But there were rheostats in the tiny instrument. In spite of his precarious clinging position and the bounce of the heavy car, Agent “X” managed to move them with sensitive fingers, electing sounds according to the wave-length of their vibrations. The rumble of machinery, coarse and long-waved, was easily excluded.

Presently the confused sound of men’s voices made the amplifier’s earphone buzz. Another turn of the rheostat and Agent “X” could hear the voices of those inside the car distinctly. Two men were talking together in the back seat. They were only a foot or two away. One seemed glum, harsh.

“I’m gettin’ fed up, Lefty. If I don’t get outa this damn thing soon I’ll go nuts. It’s the screwiest racket I was ever in — an’ with these bugs makin’ everybody sick it gives me the creeps.”

“You’re gettin’ paid, ain’t you?” snarled the other. “You get a cut on everything that comes in. Ten grand tonight fer squirtin’ a little juice into the son of a millionaire mug. It’s a good racket, if you ask me. I don’t blame the bosses for playin’ it to the limit.”

“They’ll go a couple of rounds too many, if they don’t look out. The whole town’s gettin’ sick. What if some of us comes down with sleeping sickness! I tell you it’s givin’ me the creeps.”

“You’ll stick with the rest of us,” the other replied ominously. “You can’t get out of Branford till the bosses are ready to let you go. Quit yer damn grouching.”

There was a few seconds of silence. Agent “X” had almost stopped breathing. His guess that these men were only underlings had been correct.

THE Agent eased his cramped position. It was no mean feat to cling with a single arm to the spare tire casing, where every irregularity in the road caused the maximum of jarring vibration. After a moment he resumed his grip and pressed the amplifier to his ear again. The grumbling voice of the complainer came gratingly.

“Some guy’s goin’ to get wise if we don’t quit, and quit soon. There’ll be dicks after us some night.”

“You can’t win without takin’ a chance. There’s a whole bunch of rich mugs that ain’t been shaken down yet. The Channing girl comes tonight, Dillon’s goin’ after her.”

The Agent’s heart leaped. He felt a coldness creeping over him. The Channing girl! That would be Paula Channing, Betty Dale’s cousin — the girl she said she was going to visit tonight. The hideous ring of microbe spreaders had marked her for their next victim. She, too, would be inoculated with encephalitis.

For an instant Agent “X” considered dropping off the car and giving the Channings warning. But he might never have a chance like this present one again. His warning might save Paula Channing from sleeping sickness — but it would mean that his desperate effort to trace the criminals would fail. The future destiny of a whole city lay almost within reach of his hand now.

All during the time he had clung to the car, “X” had been on the alert to note any symptoms which might appear in himself as a result of the hypo injection. So far there had been none. This relieved him. Receiving the serum had been an unavoidable part of his scheme, but he had been more worried than he had admitted to himself as to the possible effect on his own system — whether or not it would produce results which would make him unfit to carry his plan to its conclusion.

The car had left the boulevard now. It was threading a series of dark, winding streets, penetrating into the heart of Branford’s slums.

Abruptly the car slowed. Dark buildings shadowed the street ahead. Closed warehouses; a deserted factory; a huge gas tank rearing up into the night sky like some ungainly monster. A sluggish inlet of the river penetrated here. A few empty barges creaked on their moorings. The region was darkly sinister, the air dank.

The car swung sharply. Its headlights pointed toward the door of a low garage.

Instantly the Agent dropped to hands and knees on the street, backing off behind the car to the shadow of a fence.

One of the men got out and unlocked the door of the garage. The door slid back on smooth-running rollers, and “X” caught a glimpse of the interior. It was an ordinary one-car garage with a cement floor. The man who had opened the door backed against a wall as the car rolled in. The roller door slid shut

The Secret Agent’s eyes gleamed. He had trailed the members of the germ-spreading band to their lair, or at least within close range of it.

He let two minutes elapse before he crept forward. Then he took a set of chromium tools from his pocket. Opening the lock was child’s play to him. But he listened long and carefully with his amplifier before rolling the door back. No sound of voices issued from within.

Cautiously he slid the door back an inch at a time He stepped inside, every sense alert, and stopped to avoid running into the rear of the car. Still there was no sound. The Agent flashed on a small light.

He gasped in sheer astonishment then. The floor and three blank walls were all that showed up in the beam of the light. There wasn’t even a small door in the rear — no visible exit by which the men could have left. But that was not the mystery that baffled him most. It was the big car that he searched for in vain. That too, had vanished as though black magic had been used to dissolve it into thin air.

Chapter XIII

AGENT “X” stood dumfounded. With his small light he continued to search the interior of the garage. He hardly believed his own eyes. It was as though the drug he had taken to slow his pulse, or the serum injected into his veins, had affected his sight. Then he bent forward. A fresh drop of oil glistened in the center of the garage floor — proof that a car had recently stood there.

“X” walked around it, tapping the cement. It seemed solid, forming a firm foundation. At the sides and end of the garage it appeared to be flush with the wooden framework.

He turned his light upward. It revealed nothing but dusty rafters and the roof above his head. For a moment Agent “X” stooped and pressed the disc of his tiny amplifier to the hard cement.

A faint, hollow roaring reached him. Second by second the sound diminished, then ceased altogether in a barely perceptible jar. Silence followed. But the Secret Agent’s eyes were burning with excitement.

Mysterious as had been the disappearance of the car, he believed he had found the explanation. But proving it would take time. And just now minutes were precious. Paula Channing had been marked for inoculation — and Paula was Betty Dale’s cousin.

The thought that his blonde ally would be close when one of the night-prowling germ-spreaders attacked troubled Agent “X.” Betty and the Channings must be warned before anything else was attempted. He left the garage, locking the sliding doors behind him. He walked swiftly away through dark streets. He was definitely on the trail of the criminals, now. As soon as possible he would take it up, return to this place, and systematically search the garage.

The lighted front of a small cigar store glowed in the darkness and he hurried toward it. He flipped the pages of the city telephone directory, then plunged into a booth. His fingertip made the dial snarl as he called the Channing’s number. The voice of a servant answered and Agent “X” spoke quickly.

“Doctor Preston speaking. I believe Miss Betty Dale is visiting Miss Channing. I’d like to speak to her.”

The servant’s reply was impersonally precise.

“Hold the wire. I’ll tell Miss Dale you are calling.”

Agent “X” heard the servant’s footsteps receding. A full minute of silence passed. The servant did not return. The voice of Betty Dale that “X” was eagerly awaiting did not reach his ears. Then, suddenly, something else did!

Faint at first, the sound spread like a clutching chill through the Secret Agent’s mind. It was a girl’s shrill scream. The crashing tinkle of breaking glass followed it.

Fiercely Agent “X” clattered the telephone receiver on its hook. He cursed the servant. Dread made him tremble. Long since, he had cast out fear for his own safety. The strange and terrible dangers his work led him into had built up immunity to personal fear. But he could not stifle his emotions where Betty Dale was concerned. She was the one person, outside his chief in Washington, who knew the nature of his activities — the one whose faith and loyalty had never wavered. He couldn’t calmly contemplate the possibility of danger overtaking Betty Dale.

Agent “X” slammed the receiver on its hook and tore out of the booth. Like a man possessed, he strode through the dark deserted streets till he spotted a single cruising taxi. Leaping in, he pressed a five-dollar bill into the driver’s hand, gave the address of the Channing house.

“Step on it! Get there as fast as you can!”

THE driver responded instantly. Passengers were scarce in Branford these days. The heavy cab lurched forward, whined around corners, bored steadily ahead. Traffic regulations were non-existent in the nightly quest for the gorillas. In the dark interior of the cab the Agent’s hands worked miracles, changing his disguise once more to that of Doctor Preston.

White-lipped, tense, he waited impatiently as the taxi crossed the city. It rolled at last into a short driveway that led to a handsome brownstone house. Agent “X” flung the cab door open and bounded up the steps of the house.

It was seconds before his ring was answered. Those seconds seemed eternities to Agent “X.” Then the door was opened cautiously by a servant whose hands trembled. His face was livid and fear writhed like a live thing in the depths of his eyes.

“X” spoke hoarsely, his fingers clutching the man’s arm.

“What has happened!”

“Your name, sir?” whispered the servant.

“Doctor Preston. I called fifteen minutes ago,” snapped “X.” “I asked to speak to Miss Dale on the phone. You didn’t send her. What has happened?”

The frightened servant admitted Agent “X” into the hall.

“It is terrible!” he gasped. “Another doctor is here already. The ape attacked, sir — just as you called! It smashed a window. It entered the room where Miss Paula and her friend were talking. Both have been bitten!”

The man’s words cut through the Agent’s heart like a cold knife blade. The human horror he was fighting had struck abruptly, fearfully close. Betty Dale attacked!

His mind cringed away from the fact — shuddered as he seemed to see her face set in gruesome rigidity. All the vivid life, all the young loyalty of her, frozen in the cast of death. A groan escaped the Agent’s lips. This savage shock was more awful than the impact of gun-lead.

The old wound in his side — the wound that he had received years ago on a battlefield in France — throbbed with pain. He had to shake his head to clear his faculties. That wound in his flesh seemed the sign and symbol of the indomitable, driving will that would not let him submit to defeat. The wound had not killed him — and even this crushing blow could be mastered. He would fight — fight for her sake now, as well as for the humanity he had struggled for impersonally.

“Where is she? Take me to her at once!” he commanded.

“This way, sir.”

The trembling servant led “X” along a hallway to a room beyond. Betty and Paula were there. With them was a doctor, talking to Paula’s father, Mr. Channing.

The Agent’s throat tightened as his eyes rested on the sunny gold hair and sweet face of Betty Dale. She turned toward him as he entered. She started — then, even in the terror and distress of the moment, she remembered not to betray him. Nothing could ever make her do that.

“Doctor Preston,” announced the servant. “He telephoned you, Miss Dale. I was coming to tell you when — it happened. Then I forgot.”

“I heard a scream over the wire,” said “X.” “I got here as quickly as I could.” His words were meant for Betty, and he saw the warm, sweet look she gave him in return.

Mr. Channing turned a haggard face. “James has told you, of course, doctor. One of the apes came through Paula’s window. It broke open a shutter. Both girls were attacked — my daughter and my niece. We need all the medical advice we can get. If you have anything to offer, for God’s sake, tell us…. This is Doctor Barnes, Doctor Preston.”

“X” nodded to the short, thick-set physician who was attending the wounds in the girls’ arms. He looked efficient, but “X” saw that his fingers were not steady.

THE Agent lifted Betty’s wrist and stared at the livid teeth marks on her white skin. He shuddered, knowing that they had been made with a murderous device. The girl’s eyes met his bravely.

“You find me in trouble again, Doctor Preston,” she said. Then she explained to the others. “I was caught in the mob that tried to burn the institute, as I told you. In the crush I fainted and fell in the street. Doctor Preston here happened to find me and took me to my aunt’s.”

No one was listening. Paula, her father, and Doctor Barnes seemed overcome with dread, each expressing fear in a different way. Doctor Barnes was tense, trembling, absorbed. Channing watched him in gloomy silence. Paula Channing was biting her lips and trying to keep back her tears.

Betty Dale’s lips trembled in a smile that touched the Agent’s heart. He had seen her smile before in the presence of danger. But never had she come under the shadow of such horror as this. Already, he knew, the dread bacilli were circulating in her veins. Nothing that he could do would save her. Nothing — unless—

Her voice broke into his desperate thoughts. “I might have expected it, doctor, coming to Branford as I did. I knew it was a rather foolhardy thing to do. But think what a story this will make! Girl Reporter Sleeping Sickness Victim! This is one time I’ll crash the front page of the Herald.”

Channing gave an impatient exclamation. But Agent “X” understood Betty Dale’s bravado. She was trying to keep up her own courage and comfort him at the same time. The pallor of her face showed that she was fully aware of what that wound on her wrist signified. She had seen the effect of the disease in Branford. But her contact with Agent “X” had helped to give her Spartan courage. Under pretext of examining her wound, he pressed her slim fingers, noticing their coldness. Betty was keeping calm through sheer power of will.

A sudden impatience seized Agent “X.” A light like a living flame burned in his eyes. Hatred against the criminals rose in his heart like a red wave. They had brought Betty Dale into the shadow of a slow and horrible death. He must follow the one lead he had uncovered — the lead of the mysterious garage.

Before he left the Channing house, he drew Betty Dale aside. There was a grim smile on his lips as he took her cold hand.

“Don’t worry, Betty. The men who did this have the serum that will cure sleeping sickness. Tonight I trailed them close to their hideout — and tonight I plan to follow them farther.”

Chapter XIV

THE Agent’s words had a vibrant ring in them. They were meant to reassure Betty Dale, and they did. He wanted to lift the cloud of fear from her mind while he followed the hideous crime trail.

“Be careful,” she breathed pleadingly, forgetful now of herself.

Agent “X” was like an avenging nemesis as he went back to that section of the town where the mysterious garage was located. And once again he unlocked its door. Then, with the patience of Job, he set about examining the building. He had a theory. There was only one possible explanation for the enigma of the disappearing car.

Carefully he began a minute scrutiny of the floor, playing his tiny flashlight around the edges of the concrete. There was a two-by-four framework around its base. This overlapped the cement. He shifted his concentration to the sill of the door over which the car had passed, drew out a small sharp knife from his pocket and pried at the sill. At last he rose with brightly gleaming eyes.

Next he searched the building’s interior. His fingers roamed over the inside of each beam. His eyes followed his flashlight, probing, searching. Suddenly he stopped, hands tense.

On the inside of a supporting beam, close to the door, he found a tiny electric button. It did not control the overhead lights. The switch of that he had located easily at once. This one had been deliberately hidden, tucked away in a place that no one, unless he searched patiently, would ever find.

Agent “X” paused a moment. Was it a signal button? Or did it operate the concealed mechanism that the Agent’s keen mind had guessed existed?

He took a chance and pressed the button. He waited. A second passed. And then a strange thing happened. The concrete he was standing on, the floor of the garage, began sinking slowly. With the gradual movement of a smoothly running elevator it dropped below the level of the side beams that overlapped it.

It was an elevator, cunningly supported on plunger rods beneath — a wooden platform finished off with a thick covering of concrete. As it sank, with the Secret Agent upon it, he seemed to be going into the bowels of the earth. The floor had dropped twenty feet, and he was in a dark, damp well before anything else showed. Then, at the rear of the pit left by the elevator, twenty feet below the back of the garage, the top of an underground doorway showed in the glow of the Agent’s light.

As the concrete platform sank, the doorway seemed to rise. The elevator stopped at last, flush with the bottom of this hidden door. The amazing cleverness of the criminals was proved by this device. These were the most elaborate precautions against shadowing that he had ever seen. Years might go by and no one would ever guess the secret of that ordinary-looking garage with its sinister purpose.

He found that the door in front of him rolled sidewise. His fingers manipulated it. A cold draft of air struck his face. He waited tensely. But no sound came down the corridor he had opened up. It was densely dark. The only noise was the faint purring of the electric motor that had operated the cement platform. This was in a small chamber at the side of the passage. The elevator seemed to be automatic. It was his pressure on the button that had started the motor and made the floor descend.

He stepped into the corridor, closing the door after him. The elevator ascended. Its rise was automatic, too, brought about by the closing of the door.

DARKNESS and mystery lay ahead. Never had Agent “X” felt so completely alone in any battle with criminals. Entering this underground corridor he had stepped into another world, a world of unknown danger and terror. He had no idea what he would find. At any moment, death in some ghastly form might spring out of the darkness upon him.

He moved forward cautiously, groping with his hands along the corridor walls. The passage was straight for a few yards, then began a long curve to the left.

The Agent’s mind was at work. He had an uncanny sense of direction that had often stood him in good stead. It was operating now. The corridor seemed to him to be heading toward the group of old buildings surrounding the big gas tank he had seen. Every few moments he stopped to listen, but could detect no sounds. He took another chance and flashed on his light.

A hundred feet ahead he saw the oblong of another door. He approached this stealthily, ears acutely attuned to the slightest sound, nerves taut. He rolled the door back. And there in front of him loomed the big car that had disappeared. Excitement made the Agent’s heart race. Here was concrete evidence that he was progressing toward his goal.

He moved cautiously past the car; saw a door in front of it in the rear of this underground garage. The door was fastened with a lock as elaborate as that of a safe deposit box. No ordinary key was used here.

Secret Agent “X” took out his kit of chromium tools. With elaborate care he set to work. Many tests were required with one of his small, delicate instruments before he ascertained the exact nature of the lock. Then he inserted a spidery skeleton key of resilient steel wire that adapted itself to the complex tumblers. A gentle movement of this and the door opened.

The Agent pocketed his tools, groped in the darkness again. His hands encountered what appeared to be a flight of steps. He began the ascent of these cautiously. He was coming nearer and nearer the criminals’ hideout. He knew that death lurked in the blackness around him. Caught prowling here, his life would be worth less than nothing. But the strange, burning glow in his eyes increased. He was experiencing the thrill of the born man-hunter, stacking his wits once again on the other side of the scale against the desperate cunning of ruthless criminals.

He continued to climb the dark stairs until he had almost reached ground level. A faint, pungent smell assailed his nostrils. It was the clinging, unmistakable odor of gas. The ground around him seemed saturated with it. This confirmed his belief as to the direction the passageway had taken. The old gas tank, steel walled like a fortress, was the lurking place of the germ spreaders. But that there were other secret entrances and exits he did not doubt.

THE stairs ended by another door. This opened easily. He walked along a chill concrete passageway, heard the faint sound of voices. They might be far off, or muffled by thick walls. He could not tell which, yet. He moved ahead, and the voices grew fainter. Back again, and they increased in volume till he passed a certain point. There must be doors ahead; but the Secret Agent stopped where this murmur of voices sounded strongest.

Once again he took out his delicate amplifier — the instrument that had plumbed the secrets of many desperate criminals. Quickly he opened it, pressed the small microphone to the wall, put the ear piece to his head, and fingered the rheostats.

It was a simpler task to isolate these voices than it had been to hear in the moving car. There was little else to interfere. The passages, deep underground, were strangely still.

Two men were talking. The words they used were not in gangster dialect. This was the speech of more educated men. The Agent’s heart leaped. It seemed he was now listening to those who guided this hidden and hideous racket. He was separated from them only by a foot or two of steel and concrete. One voice was deeper than the other. The higher-pitched voice was faintly familiar to “X.” He listened spellbound. The men were arguing fiercely. The deeper voice was sneering, contemptuous.

“We’ve gone too far to stop at anything now! At my orders the children of the city commissioners, the mayor, and the aldermen have been inoculated. What have you got to say to that?”

A furious curse came from the lips of the other man.

“You should have asked me about it first. I told you—”

“It makes no difference what you told me! I’m running things from now on. You’ve lost your nerve. I’ve been watching you. I’ve seen it coming. You’re going to take your orders from me like the rest of them whether you like it or not. This racket’s almost washed up. The monkeys are dying. People will be getting wise to us pretty soon anyway. I’m going to get a big hunk of money and then skip — that’s why I dropped the mayor a letter this afternoon.”

“You sent the mayor a letter?”

“Yes. One of his kids has got sleeping sickness. I offered to sell the city all the serum we have left for a million in cash.”

“My God — you’re crazy! They’ll know it’s a racket They’ll never pay. You can’t hold up a city.”

“Why not? They’ll be glad to raise the money to save their kids, I tell you. And it will be our last play. After it goes through, we’ll clear out.”

“But we haven’t enough serum left to— The apes are dying, and Hornaday says—”

A harsh, cruel laugh sounded.

“Serum be damned! We’ll get our money. We’ll hand out water if we have to. They’ll never know the difference — until it’s too late.”

Secret Agent “X” tensed with fury.

“The city will raise the funds, I tell you,” the deep voice continued. “The board of aldermen can do it. There’s more in the public treasury than there is in private pockets.” The laugh sounded again. “You can’t back out now! You’ve gone too far to save your own face, and I’ve got enough on you—”

The last words were lost in a volley of curses. The taunting, deep-toned voice cut through them. “You weren’t cut out to be a big shot. You lack guts. And now you’re taking your orders from me.”

Agent “X” strained forward, listening anxiously to catch every word. Who were these men? The walls made their voices distorted. Through the amplifier it was hard to recognize them, and yet—

Then suddenly his body stiffened. A sound had reached him through the other ear. It was on his side of the wall — the sound of movement in the passage.

The skin along his scalp tightened. A sense of danger made him turn abruptly, muscles rigid. And in that instant an overhead light flashed on.

In its glare Agent “X” had the reeling sudden sense of being in the midst of a horrible nightmare. For a half-dozen hideous, hairy faces were staring at him. The strong light revealed them plainly. Creatures that seemed neither men nor apes, who had crept upon him as he bent intent over his amplifier. One of them gave a hoarse cry. Before the Agent could move, they leaped upon him.

Chapter XV

“X” tried to draw his gas gun out, but the apelike forms were too close. They appeared as gorillas until a human voice issued from behind one hideous face.

“Get the rat — kill him.”

The truth of a thing that the Agent had already guessed was now apparent. These prowlers of the night who had been terrorizing the city, spreading disease and horror, were not gorillas, but men dressed up to look like them.

It explained the strange encounter he had had on his first night in Branford, explained the mystery of the toothlike injector; explained how the crime ring controlled their movements and inoculated the victims they selected.

In a blasting wave of fury, Agent “X” fought, but there were too many of them. They rained murderous blows on his head with fists encased in repulsive hairy black gloves. Another spoke hoarsely.

“Don’t kill him! Wait! The bosses will want to know about this. They’ll want to talk to him and find out who he is.”

In this speaker’s voice was a shade of fear. The mystery of the Agent’s inexplicable presence there seemed to have impressed one at least of these grotesque creatures.

But they didn’t handle him gently. The futility of fighting was soon borne home to him, and his heart leaped at mention of the “bosses.” To be taken before them, to find out who they were, was what he most desired.

He collapsed under a shower of vicious blows, lay limp as two of them picked him up. One had a drawn gun pressed against the Agent’s side.

“Keep quiet, rat — or I’ll burn your guts.”

This was gangster talk. Here were men of the same calibre as those who had talked in the car; perhaps the very same individuals.

Agent “X” made no reply. He was thrust forward along the dim corridor, thrust through one of the doors he had seen at the passageway’s end.

The sense of being in a nightmare persisted. The costumes these men wore were so lifelike, the hoods over their heads so hideously real, that they seemed like apes with the power of human speech. No wonder a whole city, seeing them only at night, had been fooled. Here was more evidence of the daring and cunning of the fiends.

“How didja get in?” one of them demanded hoarsely. But still Agent “X” remained silent.

They took him through another door into a high-ceilinged windowless room which had the chill of steel and concrete.

He looked around in wonder, expecting to see the two other men. But the room held no one save those who had come in with him.

One of these went to the farthest wall. Agent “X” saw that it was formed of steel plates welded together. The ape-like man rapped out a series of signals with his knuckles. He stepped back, and a small slit opened in the steel wall. Through it a voice issued, the deep voice of the man Agent “X” had heard before.

“What do you want?”

“We caught a guy in the hallway, boss. He was listening. We got him here.”

The air of the room became deathly still. It seemed charged suddenly with the power of hate — and fear. Agent “X” could feel eyes fixed upon him — eyes that bored out through that single slit in the wall. He understood now that he was not to see the brains behind the racket after all. They had taken clever pains to protect their identity. But the voice sounded again, harsh with fury and amazement.

“You found him in the passage outside, you say? He had come all the way in?”

“Yes, boss.”

“Bring him closer!”

The men dressed as apes obeyed. Agent “X” was pushed nearer the wall, hands pinioned to his sides.

“Turn a light on his face.”

This was done also, and again Agent “X” had the uncanny sense that the eyes behind the wall were a tangible force — a force of evil unparalleled in his experience.

“Who are you?” the voice said. “Speak quickly — or you die.”

“An agent of the governor,” said “X.” “I came to Branford to investigate the epidemic.”

“Search him!”

THE Agent’s pockets were searched. His wallet was brought out. In the name place of it was a card bearing the words, “Doctor Preston, State Sanitation Department.” One of the men passed it through the slit in the wall. There was another moment of tense silence.

“And how did you get in here?” the deep voice abruptly demanded.

For a bare instant the Secret Agent was baffled. His identity was something he guarded with his very life. He did not intend to reveal it now. Yet how could he explain his entrance without giving away the fact that he was not what he appeared? One of the apelike men, fingering the Agent’s kit of chromium tools, answered for him.

“He’s got house-breaking gadgets here, boss. He must’ve picked the locks.”

The man behind the screen laughed mirthlessly.

“A doctor who thinks he’s a dick, eh? Pretty smart to get in here — a little too smart. You’re investigating the epidemic, you say?”

“Yes.”

“And how much do you know about it?”

“Enough,” said “X” quietly.

His piercing gaze swept the room, figuring his chances of escape. They were nil now. All six of his captors were alert. They had taken his gas gun from him. To make a break now would invite quick death.

“And you are all alone?” asked the voice.

“Yes.”

“Go to the door and see,” snapped the man behind the wall to those who were his underlings. There was fierce suspicion in his voice. A minute or two of silence followed while one man left the room. “X” could hear the others breathing tensely. The man returned.

“There’s nobody else, boss. He even locked the doors behind him.”

The harsh laughter of the man behind the steel sounded devilishly.

“You came to investigate the sleeping sickness, doctor! You shall have some first-hand experience of it!”

For an instant, he struggled fiercely. It was an involuntary reaction. The laugh of the man behind the wall rang in his ears.

“That frightens you, doctor! You prefer to study sleeping sickness at long range. But the ideals of medicine must be upheld. You shouldn’t hesitate to sacrifice yourself in the interests of science. We’ve developed cultures which vary in the degree of their potency. We’ll give you grade A. Its effects are most rapid.”

The men around “X” waited, except one who moved close to the steel wall. A tiny door opened outward below the eye slit. One of the strange hypodermic injectors in the form of teeth was thrust out by the man inside.

“It is ready,” he said harshly. “Give our doctor guest a forearm injection.”

At that instant time seemed to hang suspended. The Agent’s heart almost ceased to beat. Anticipating that he would attempt another break, four of the five men held him. Another pressed a gun at his back. The sixth, the man with the injector, approached.

“Roll up his sleeve!”

THE quick order was obeyed. The Secret Agent’s arm was shoved forward, bared to the elbow. With impassive cruelty, the man with the injector thrust the strange thing out. A thumb lever snapped the metal teeth open. Agent “X” got a brief detailed glimpse of this hypodermic instrument that had fooled a whole city.

Then the sharp teeth of it sank into his arm. The stabbing pain shot to his shoulder. He saw the hairy, gloved fingers of the man squeeze the injector device. The teeth were withdrawn. He, too, was now harboring the bacilli that had brought terror to Branford.

For a moment the room rang with peal upon peal of mocking laughter which issued from behind the wall.

“You won’t have long to wait, doctor! Our grade A culture is remarkably efficient. Its microbes produce the most poisonous virus of all. So far we have not used it — and I shall be interested to see just how efficacious it is. Meanwhile, you may wait and study your own symptoms. Shall we provide you with a notebook and pencil, doctor, that your experiences may not be lost to posterity?”

Agent “X” remained silent. His body was rigid, apparently, with fear. But it was the rigidity of deep emotion. He must make as much use as possible of the little time left him.

“Take him to room G,” ordered the man behind the wall. “See that he does not have his little playthings with him. One of you keep an eye on him until—”

The Agent’s gas gun, amplifier, and tool kit were removed. His other pockets were searched and emptied. The man with the gun and two others led him out into the corridor. He was pushed along it to a rusty iron door. The door was yanked open, the Agent was thrust inside, and a bolt on the outside was shoved home.

There was a small peephole in the door. The man in the corridor clicked on an overhead bulb, looked in for a moment, then walked off. Agent “X” was alone to face the slow relentless encroachment of the encephalitis bacilli, the germs that would bear him to the land of the living dead.

Chapter XVI

HE looked tensely around the room. It was windowless, exit-less, except for that one bolted door. A couple of old oxygen cylinders were tumbled in a corner. There was not even a chair. The room had apparently been used as a storage chamber in former days by a now defunct gas company.

The Secret Agent paced back and forth. Another man might have given in, resigned himself to the inevitable, but the burning, flashing light of battle was still in the Agent’s eyes. Suddenly hope flared in his mind.

He recalled the ride along River Boulevard in Garwick’s car; recalled the injection of serum he had received as Garwick’s son. Would not that nullify the virulent germs in his blood for a while? His body was now a laboratory where a horrible battle was taking place — a battle between a horde of dread invaders and the serum.

With the terrible pressure of lack of time eased somewhat, Agent “X” could think more freely. He went back over the events of the last hour, recalling in every detail what he had seen — and heard. The man behind the screen had mentioned a name that had made his blood tingle. Hornaday! The young scientist from Drexel Institute was mixed up in this somehow.

It was more than possible that Hornaday had provided the serum with which the criminals were effecting cures. Was the brilliant young student working willingly with these fiends, or had they taken him prisoner? Where was he now? Agent “X” resolved to find out.

His pockets had been searched and emptied. But the gangsters dressed as hideous apes had not known with whom they were dealing. Neither had the man behind the steel wall known. And in his battles of wit with criminals, Agent “X” always tried to keep an ace in the hole.

Deep in the linings of his clothing, padded with strips of felt, were other pockets that hadn’t been discovered. The Secret Agent went through these, taking stock of the things that had been left him. A tiny cylindrical flashlight with a bulb hardly larger than a grain of wheat. A vial of anesthetizing drug with a minute needle injector. A few compact, portable make-up materials. Another miniature tool-kit contained in the hollow barrel of what appeared to be a fountain pen.

This latter Agent “X” fingered. The pen point of it unscrewed leaving a strong metal socket into which the slender tools contained in the barrel could be set. These extra tools had been selected with the greatest care. There was a small screw driver, a rat-tailed file, an auger, and a diamond studded bit.

Agent “X” approached the door and examined it. But there was no lock. There was no keyhole on the inside. The old-fashioned bolt that shuttered the door offered a greater obstacle to the Agent than any modern lock mechanism could have done. All his detailed studies of tumblers were futile in the face of it. The fittings of the bolt were riveted to the door. The rivets’ heads came through to his side.

Given hours in which to work, he knew he could file these rivets off. But time was too precious. He had overheard the astoundingly cruel scheme that the head criminal had outlined. Knowing that their cards were almost played out, they would soon be leaving Branford; leaving terror and suffering behind them; leaving Betty Dale ill with a malady that no doctor could cure.

“X” could not tell how effective the serum injection he had received would be. He could not tell how much time there was left for him to work in. He must escape while his nerves and his muscles were still unimpeded by the onslaught of the disease, before the paralyzing coma of encephalitis disabled him. When that happened, he would be out of the running for a long time — perhaps forever.

He studied the door, his quick brain devising and discarding a dozen schemes. Suddenly his eyes brightened. He stared at the light bulb above his head. It hung three feet from the ceiling. If he jumped, he could reach it. And there above the bulb was wire. Wire — that was the one thing he needed.

With deft fingers he inserted his diamond-set bit into the socket of the tiny penlike tool. He measured the rivets of the outside bolt with his eyes, estimated the length of the bolt. Then he began drilling eight inches behind it on a line that was parallel.

Quickly, expertly, he worked. Strong alternating movements of his wrist and the teeth of the bit sank into the metal. Small curlicues of steel dropped away beneath it, fell to the floor. He kept a sharp ear out for footsteps in the corridor.

The steel of the door was nearly an inch thick. It took him ten breathless minutes to drill the hole behind the bolt.

Then he walked back to the center of the small room under the light. He leaped up, caught the wire above the bulb, yanked it from the ceiling. The room was plunged instantly in darkness. But he had his own small light for later use. Now he worked in the stuffy blackness; tearing off the insulation, drawing out slender copper strands.

At last he had a wire over two feet long. He brought the ends of this together, twisted till the double, foot-length wires had become as one, with a small loop left at the end.

He approached the door again, bent the wire carefully, thrust the loop through the hole he had drilled.

A minute of careful movement. The Agent manipulated the wire with deft fingers. Then he was rewarded. He had caught the loop over the handle of the bolt.

A slow, steady pull and he drew the bolt toward him. It squeaked once. He waited, listening with every nerve taut. Another pull, and the bolt’s end slid out of its socket The door swung open.

But Agent “X” did not move. If they caught him again, he knew he would never have another chance. He could win now only by caution and by the exercise of all the cunning he possessed. The odds against which he was pitted seemed hopeless. He waited inside the door of the dark room until footsteps sounded. The gangster detailed to keep an eye on him was coming back.

“X” waited until the man was opposite the door. Then, almost in one movement, it seemed, he thrust the door open and sprang out into the dim corridor.

The gangster, still clad as an ape, had the hairy, masklike hood of his costume thrown back. He gave one hissing gasp. It was cut short as Agent “X” smashed a balled fist against his chin. The blow was calculated, delivered by a man who had had training as a boxer and wrestler.

Before the gangster collapsed, Agent “X” slipped an arm around him; pulled him into the dark room.

There he worked quickly, drawing the man’s strange gorilla costume off his body. The gangster was tall, brutal-looking, with a face almost as ugly as the ape mask he had worn. The furry costume had made him seem huge.

Agent “X” flashed his small light on the man’s features. For seconds he examined them, eyes strangely intent. Then he drew his hypo needle and his make-up set from his pocket. He had a tube of the plastic, volatile material that he always carried with him. There was also a thin vial of whitish pigment. He spread this over the gangster’s face till his features appeared gray as death.

Over this Agent “X” spread the make-up material and quickly molded it into new lines. He had no mirror. He was working from memory only. But the disguise he wore himself was impressed indelibly on his mind.

Under his deft fingers, the features of the unconscious gangster changed. To the casual glance they became the features of the man called Doctor Preston.

“X” did not use all of his material. He saved out as much as he could, pocketed it. No telling when he might need it again! Next he injected nearly a gram of his anesthetizing drug into the gangster’s veins, making sure the man would stay out even after the effect of the punch had worn off.

Standing up, flashing his light on his handiwork, Agent “X” smiled, grimly satisfied. The man lying on the floor appeared as Doctor Preston, with the pallor and rigidity of sleeping sickness upon him.

Agent “X” changed his own features as nearly like the gangster’s as he could, then stooped and picked up the horrible gorilla costume. He slipped the hood of it over his own head, closed the zipper fastenings that the long, dark hair prevented from showing.

He could see through the eyeholes, breathe air through the nostrils. A downward pressure with his chin, and the gorilla mask responded in a hideous way, opening its mouth, showing white fangs. No wonder the citizens of Branford had been terrified and thoroughly convinced that the thing they saw was one of the escaped gorillas from Drexel Institute.

The Agent’s next moves were purposeful. Before he left this place, before he made an attempt to capture the criminals, he must investigate the mystery of Hornaday’s disappearance, and learn what he could about the curative serum.

Walking easily, naturally, as though he belonged there, he moved along the corridor. The dim overhead light cast a hideous contorted shadow at his feet — the shadow of a monstrous ape.

There were five or six doors along this hallway. Most of them gave into deserted, dust-laden storage rooms. Listening at one before he opened it, he heard strange animal sounds. There were rustlings, the scrape of claws, an occasional hoarse grunt. In the air, seeping around the cracks of the door, was a pungent animal smell.

With tense fingers the Agent unbolted the door, stepped across the sill. Huge iron cages, looking as though they had been purchased second hand from a circus, ranged the walls. In them were the great, hairy forms of real gorillas — the anthropoids that had been stolen from Drexel Institute. Five of the cages were empty, however. There were only four of the animals left. These seemed dazed and sickly.

Heads rolling on slack necks, eyes goggling horribly, hairy skin hanging loosely, they clung to the bars and looked at him. One wrinkled its nose, snarled gutturally in its furry chest.

THE apes, he could see, were not well. No wonder the criminals’ supply of serum was running short. The anthropoids from which they obtained it were succumbing to the unwholesomeness of this damp, airless place. The presence of chill steel and concrete made the building unfit for human or animal habitation. Hideous and fierce-looking as these great beasts were, Agent “X” felt sorry for them.

The way they had been treated was further evidence of the inhuman attitude of the criminals. At the institute the gorillas had been properly fed and cared for. They had been made as comfortable and happy as possible, and used as living laboratories only that mankind might combat a terrible disease.

He moved around the room, saw a cluttered table with bottles and syringes upon it. These he examined quickly, interest flaming in his eyes. But here was none of the finished product. That apparently was kept behind the steel wall, in the room from which the deep-voiced man had spoken.

The Agent left the apes, entered the corridor again, stopping before the next door. This was bolted also. His heart beat faster. He slid the bolt back softly. There was no telling what the room might contain.

He groped for and found a light switch beside the door; clicked it on. Under the glow of the ceiling bulb, he saw a skeleton-thin man lying on a narrow cot.

Wasted as his face was by disease. Agent “X” recognized the man. He had seen pictures of him in medical journals, and at Drexel Institute also, in the office of Doctor Gollomb. This was Hornaday, the worker who had so mysteriously disappeared.

Agent “X” leaped forward. Something on the man’s wrist gleamed in the light, catching his eye. Metal cuffs, the steel links of which were snapped to the bed. Here was mute evidence of what he had suspected. Hornaday was a slave of the criminal gang.

At first he thought the man was merely sleeping. Then he bent closer and horror crawled over his flesh. Hornaday was sleeping, but not with the normal sleep of fatigue. His skin was grayish, ghastly, showing traces of masklike rigidity. His pulse was weak. Hornaday was suffering from sleeping sickness.

Then the Secret Agent’s eyes lighted on a small syringe on a table. There was a bottle beside it containing a small amount of colorless liquid. The covering of one of Hornaday’s skinny arms was slit to the elbow.

Agent “X” rolled the cut garment up. On Hornaday’s skin several scars showed, one recent. Evidently the man had been given injections of the serum also. Yet they had not cured him.

Agent “X” picked up the syringe and bottle. He examined them, frowned. Intuition made him leap to a conclusion. He pressed the plunger of the syringe into the bottle until the reservoir was half filled. Then he leaned forward and gave the sleeping man a shot of the fluid.

A faint tremor passed over Hornaday’s blue-veined lids. A sound like a gasp came from his lips. But the jabbing pain of the needle was insufficient to arouse him from the coma. His gasping whisper stirred around the walls of the high-ceilinged room like the haunting voice of some being from another world.

Agent “X” waited tensely. The man did not move again. If anything he seemed to have sunk deeper into the strange coma. There were a couple of rickety chairs in the room. Agent “X” sat down on one.

SOMEWHERE in the big building he could hear confused sounds. The steel walls of the place distorted them. He knew the gangsters must be housed somewhere near — those who had not gone forth into the night on their deadly, hideous missions.

Agent “X” knew that before long he might be lying on a bed as this man was — among the living dead.

It was nearly half an hour before Hornaday stirred again. As the minutes passed, a slow change came over him. The Agent, alert to small details, noticed this. His eyes were tensely watchful.

The liquid in the bottle that “X” had injected was working slowly in Hornaday’s system. It had been necessary for the circulating blood to carry it around many times. Now its effect was evidenced in quickened breathing and a slow suffusion of blood to the deathly skin.

One of Hornaday’s thin hands moved. There was something ghastly, nightmarish, in the way his clawlike fingers stirred. They seemed to be groping, groping for some hope, some desired thing that was forever beyond his reach. A moan came at last from the man’s lips. He turned his head on the pillowless cot. Slowly his eyelids slid down from eyes that still held the glassiness of his long sleep.

Agent “X” arose, bent over the man. Second by second the glossiness faded from Hornaday’s eyes. They grew brighter; the man’s sickly face assumed harsh lines of hate and fear as he stared up into the hooded features of the Agent. His lips came back from his teeth. His hands clenched. He made a throaty cry like an animal in pain.

“Hush!” the sibilant warning of Agent “X” sounded strangely in that room, coming from behind the apelike mask. “I am a friend,” he said softly.

“Friend!” Hornaday echoed the word harshly. A cackling, fearful laugh came from his lips. Agent “X” silenced it with a quickly thrust hand encased in a hairy glove.

“Listen to me,” he said tensely. “You are a prisoner of these gangsters. You want to escape — go back to the world you belong in. What if I tell you I can help you?”

Agent “X” removed his hand. Hornaday lay quiet, staring up at him. Bright, feverish spots of color flamed in his gaunt cheeks. He reached forward to clutch the Agent’s arm, forgetting that his wrists were cuffed. The steel links brought him up quickly, and he cursed with savage bitterness.

“Who are you? What are you doing here? Take off that hood and let me see your face.”

The Agent shook his head.

“You don’t know me; but I know you. Doctor Gollomb has told me all about you. They are wondering where you’ve gone. An epidemic is raging. I came to Branford to investigate.”

“And how did you get in here? What are you wearing that costume for — like the others?”

“I knocked one of them out. He’s lying unconscious now. I’m wearing this so that they’ll not suspect.”

“One of them may come at any instant. They will suspect — if they find you here.”

“I know it. That is why you must talk quickly and tell me what I want to know. I gave you an injection of the liquid in that bottle. It was the liquid that brought you back to consciousness.”

HORNADAY nodded, his mouth bitter again. “It’s a weakened solution of my own serum,” he said. “It doesn’t cure, but it brings me back when they need me. I’d rather be left to die.”

“Where’s the real serum?”

“They have it. I never see them. They only wake me and ask me questions. The last time I would tell them nothing. Then they had me tortured. Look!”

Hornaday thrust a foot from the cot. Agent “X” saw that the soles of his feet had been burned.

“They don’t care now whether I die or not. The apes are dying, too. I warned them that they wouldn’t live in this place. I don’t know what it’s all about. It’s madness. They must all be insane.”

Agant “X” had let the sick man talk on. Now suddenly he asked a question, his voice vibrant.

“Who are ‘they’?”

Hornaday blinked at him.

“I don’t know. I’ve never seen them. Several times I’ve been taken into the room at the end of the hall where they’ve talked to me through a slit in the wall, but I’ve never seen them. They seem to know a lot about medicine. But they must be insane!”

“No, not insane, in the ordinary sense of the word, Hornaday,” said “X” quietly. “They’re criminals. They’re racketeers, the worst I’ve ever come in contact with. They’ve injected dozens of Branford’s rich citizens with sleeping sickness, then sold your serum at exorbitant prices. Do you get it?”

Hornaday lay for a moment as though dazed. His forehead was furrowed in thought as he assimilated the details of the amazing plot. Then he spoke hoarsely.

“Good God — and you don’t know who they are, either?”

“I’m suspicious of one at least, but I’ve no proof to back my theory. Caution’s the only thing that will turn the trick now. A false move, and they’ll get wise and clear out — leaving the people of Branford to the ravages of this plague. Here’s what I want to know, Hornaday. Can you develop more of the serum if I get you out of here?”

Hornaday answered slowly, a feverish light in his eyes.

“I’m washed up — too sick to work. But I could direct others. They took all my notes when they had the gangsters kidnap me. But I can remember — everything. If the gorillas haven’t died — if they can be taken care of and put in condition again, or others bought, more serum could be made. We’d give the people the cure free. The institute would pay for it.”

Agent “X” breathed a sound like a sigh of relief.

“Good! You’ll have to do it — to save those who are sick now — and keep the epidemic from spreading.”

“I will!” Hornaday gasped. “For God’s sake get me out of here if you can — I’ll—”

Fear leaped suddenly into the sick man’s feverish eyes. His voice dropped to a whisper. “Listen! I hear some one coming. They’ll kill us both if they find you here!”

Chapter XVII

AGENT “X” heard footsteps, too. More than one person was moving along the hall, coming toward them. He stooped, whispered quickly in Hornaday’s ear.

“They may have seen the light already. I can’t turn it out now. If they come in — act as though you were in a coma again. Don’t talk or move whatever happens. You must live — understand — to save the people of Branford!”

Hornaday nodded, his face deathly white. The Agent had offered him hope; now there was a chance that that hope might be snatched away.

Agent “X” had noticed that there was a crack under the door of this room. That was why he dared not turn out the light. He must depend upon his wits again in case—

The footsteps stopped outside the door. The door opened and Agent “X,” bending over Hornaday’s cot, turned quickly. Two men stood there, both in gorilla costumes, one with the hood drawn back. He had the hard brutal face of a gangster.

“What the hell’s going on here?” he asked.

Agent “X” fell easily into the jargon of the underworld.

“This guy made a noise,” he said, jerking his thumb toward Hornaday. “I came in to see what it was. He musta had bad dreams.” A harsh laugh came from his lips — a laugh that disarmed the two gangsters. The man who had spoken asked another abrupt question.

“What about the other guy in room G? You was watching him. How is he?”

Agent “X” made a downward motion with his gloved hand.

“Out cold,” he grated. “Couldn’t take it.”

The other man laughed.

“The boss wants to see you,” he said. “He’s got a job he wants done.”

Agent “X” turned, following the others out of Hornaday’s room. His pulses were hammering. He was going to hear the voice of one of the bosses again. And now, playing a different role, in the confidence of this ruthless gang, he hoped to learn secrets that were as yet unfathomed.

The three of them walked along the chill hallway, into the room at its end.

The man who had spoken to “X,” the man with his hood down and his sinister face showing, rapped on the wall again. A voice spoke presently, the deep voice of one of the heads of this sinister ring.

“Yes?”

“The doctor we squirted juice into has passed out cold, boss. That grade A stuff works like nobody’s business.”

The grating laugh of the man behind the steel wall sounded.

“That is excellent. We’ll have use for that culture again tonight. Members of the mayor’s family, and the families of the aldermen and commissioners have been inoculated, as you know. Now I want one of the commissioners himself inoculated. I’m speaking of Health Commissioner Traub. We can’t have him interfering with our more ambitious plans.”

The laugh of the man behind the wall was almost satanic.

“This is an important job and I want it done quickly. I’m going to send two of you out. Who’ll volunteer?”

The Agent’s mind was working swiftly. This fiend behind the wall wanted to put Commissioner Traub out of the way just when the epidemic would be at its worst. It seemed a diabolical climax to this fearful crime wave — but behind the move Agent “X” read deep significance.

Neither of the two men beside him spoke. Here was a chance for him to leave the building unsuspected, but he kept quiet, waiting for a cue.

“There’ll be an extra grand a piece for those who do it when the job is done,” said the man behind the wall.

Only then did Agent “X” speak.

“Let me in on it, boss,” he husked eagerly.

One of the two men beside him also volunteered at the mention of money. The other tried to cut in. They began quarreling fiercely until the stern voice of the unseen boss silenced them.

“You two who spoke first,” he said.

Agent “X” waited for further instructions. These came quickly. The small door under the eye slit in the wall opened. Two of the toothlike injectors were thrust out.

“They are filled with grade A culture,” the man behind the wall said. “One or both of you can work on Traub. It makes no difference so long as he gets plenty of it.”

He gave them Traub’s address, then added a warning.

“Don’t come back till you’ve done the job. There’s a special meeting tonight in the mayor’s office. They’re going into a huddle on a certain matter. Commissioner Traub will be there. After the meeting’s over, he’ll probably go directly home. Wait outside his house and then get him. Do the thing right or you’ll have to chisel into another racket. I don’t play ball with men who fall down on a job — and I don’t hand out money to them either.” A short laugh sounded. The metal covering of the eye slit closed with an emphatic click.

Agent “X” turned. Following the other gang members he left the room, headed for one of the building’s secret exits. And at that moment a faint, chill sweat broke out on the Agent’s forehead. For he began to feel symptoms of weakness, dizziness. The terrible virus of the encephalitis bacilli was beginning to show itself in his blood. Could he keep himself going during the next hour to accomplish the daring, desperate things that must be done?

IN the office of the mayor of Branford a group of excited men were assembled. They were men whose faces were haggard with worry, whose eyes held somber shadows of fear. The mayor had just read them a letter he had received by special delivery less than an hour ago. It was typewritten, signed by a “Doctor Blank,” the name also typewritten. It offered to sell to the City of Branford serum that would cure the disease of encephalitis.

The charge would be one million dollars in cash. In the event that the offer was accepted, the letter demanded the acceptance be made known by radio broadcast from the Branford station. To prove that “Doctor Blank” was no quack, the letter gave certain references — the names of persons living in Branford who had already received treatment and were on the way toward being cured.

The mayor, a small, thin man, struck the letter fiercely as he eyed his commissioners and the group of aldermen seated before him.

“I’ve looked up these references,” he said. “It’s true. Some of our wealthy citizens have been receiving treatment. They have been cured. This man, whoever he is, is no quack.”

An alderman shot a question.

“Didn’t these ‘citizens’ you refer to give you the doctor’s name?”

“No. They don’t know who he is. The patients were taken out of their houses to be cured. The treatments were made in secrecy and the doctor refused to divulge his name.”

The commissioner of police spoke harshly. He was bending forward, staring at the mayor.

“Your honor,” he said. “In my opinion the writer of that letter is a crook — a criminal. This is an extortion racket.”

“You mean he can’t really make the cures?”

“That is not what I mean. I mean that he has deliberately spread the disease so that we will be forced to buy his cure. It explains a good deal of the mysteries that have puzzled us all during the past few weeks. It explains why the gorillas have never appeared in the daytime. Some man is keeping them under cover. The same man who stole them — the man who wrote that letter!”

The mayor nodded somberly.

“I have come to the same conclusion, commissioner. The proof lies in the fact that the families of Branford’s officials have now been victimized. This is a holdup, gentlemen!”

The room broke into a frenzy of excitement. Aldermen talked furiously. The commissioners crowded close to the mayor’s desk. Two seized the arm of the police chief and demanded that the law take steps to catch the criminals. The mayor rose to his feet, held up his hand for silence. His voice was trembling now.

“The fact remains,” he said brokenly, “that our own children are sufferers. Our doctors have found no cure for the disease — isn’t that true, Commissioner Traub?”

The head of the health department nodded. His fat face was twitching with emotion.

“It Is true,” he said huskily.

“Then,” said the mayor, “this quack or criminal — whatever you choose to call him — has the upper hand. He has the only cure that has been found. Are we going to let our children get worse and die slowly? Or are we going to vote that the payment be made from the city treasury?”

A moment of tense silence followed the mayor’s speech. Then an alderman spoke impassionedly.

“The treasury is depleted already. Red Cross work, visiting nurses, special guards, and additions to the police have taxed the city heavily. We won’t even consider payment. We won’t pander to this criminal. As a member of the city council, I demand that the police do their duty.”

Two other members of the aldermanic council turned on him harshly.

“Are you a married man, Harrison?”

“No.”

“Is any member of your family ill with sleeping sickness?”

“No, but—”

The others shouted him down jeeringly. But he shouldered his way forward, shook a finger under Chief Baxter’s nose.

“What do we pay you for, chief? What is the law doing while this criminal is at work?”

Baxter’s face turned red with embarrassment.

“The law’s hands are tied,” he answered huskily. “We don’t know who this man is — don’t know where the gorillas are being kept—”

“Can’t that special delivery letter be traced?”

“It was dropped in a corner mail box. It is typewritten. There are no fingerprints on it — I have already looked. If we accept his offer by radio broadcast, there is no way of telling where he is listening in.”

“But if payment should be made, can’t he be traced and caught then?”

“Perhaps — but if he is as clever as he has shown himself to be so far, he will devise a foolproof arrangement. I suggest that we get the serum first, then hunt him down. I’ll gladly contribute a year’s salary. My little girl is ill with sleeping sickness.”

The alderman who had objected to raiding the city treasury, the man with no victim in his family, was shoved aside and shouted down. A quick ballot was taken. It was voted by the city council to raise the necessary appropriation at once and send a broadcast to “Doctor Blank” accepting his offer.

Chapter XVIII

IN the dense shrubbery outside Commissioner Traub’s house two silent figures waited. Their hairy costumes and the masks that covered their heads made them appear as monstrous, sinister apes.

Beneath the hood he wore, Secret Agent “X” was fighting a silent, terrible battle. He was fighting with the first symptoms of sleeping sickness, now even more apparent. He was fighting to retain the alert faculties that would be needed tonight. For already he had a plan and a secret hunch. He did not know yet how many gangsters were in the secret hideout he had discovered. He knew that the police could not succeed in entering it without his help. And, before he acted, he wanted to verify a theory and arrange a course that would accomplish results. Hornaday must be gotten out; the gorillas that were left must be saved; some of the serum must be procured. He had not forgotten Betty Dale, could not forget her. Her face with its sunny frame of golden hair seemed to hover before his mind’s eye. Yet what he had to do single-handed seemed hopeless.

Nearly an hour passed before they saw a car approaching along the dark street. Then Agent “X” touched the arm of the man beside him.

“There are three others with the commissioner — we can’t get him now.”

Some of Traub’s friends at city hall had brought him home. He left them at the curb, walked into his house alone, but their presence prevented the possibility of any attack outside. Agent “X” was glad. He fingered the horrible injection device in his hand, stared at Traub’s house. The man beside him had no inkling as to his secret thoughts. But by quiet will power that the other was hardly conscious of, Agent “X” assumed the leadership.

They crept to the rear of Traub’s house. A light had appeared in a room there. Commissioner Traub was not going to bed at once. The events of the past few hours had set his nerves on edge. Agent “X” could see his restless shadow on the drawn shade. “X” spoke softly to his companion.

“I’ll go in and do the job. You stay out here. Whistle if anybody comes.”

The other grunted, glad enough to let “X” take on the dangerous work of entering the house.

The Secret Agent crept forward. Behind the hideous ape mask his eyes were glowing. Even the microbes of the encroaching disease could not dim the fire in their depths. And the serum injection he had received, coupled with his great will power, was still holding the bacilli at bay.

HERE was the sort of job he had had years of experience in. Entering a house noiselessly was no new task for him. He did not go to the lighted window. There was a door to the left of it — the door to a dark kitchen. This was locked; but the Agent still had his pen-shaped tool kit. He removed one of the hairy gloves, slid a section of the zipper fastening in the front of his suit open. The lock before him was a simple affair. A minute, and he had the door open and was creeping silently into the house.

His heart had increased its beat. His whole body was tense, every sense alert. More than his companion outside realized depended on the success of what he planned to do.

He moved down a short hall, came to the door of the room where Commissioner Traub was pacing. The door was slightly ajar. “X” caught sight of the commissioner’s flabby, worried face. Traub looked older. Tonight’s development, the letter from the mysterious “Doctor Blank,” had apparently shaken him terribly.

Agent “X” held the tooth-shaped injector in his right hand. In his left he held his own hypo needle — the needle containing the same anesthetizing drug that had knocked the gangster out earlier that night.

He opened the door quickly, crossed the threshold. Traub turned and saw him.

A look of utter astoundment made the commissioner’s jaw drop. He did not cry out. He stood there, staring at this hairy apparition that confronted him.

Agent “X,” through the eyeholes in the gorilla mask, was staring also. He was staring with the fixed, analytical intensity of a man who was a brilliant student of human nature. He was watching every faint, flickering expression on Traub’s fat face.

He advanced, holding the toothed injector in his right hand. Traub looked at that stupidly for a moment. His face grew ashen.

“Here — get out!” he roared. “What do you mean—”

He stopped speaking, backed away. Still the Secret Agent advanced. His thumb clicked the injector open. Its terrible teeth offered grim menace. Traub was like a man stricken with palsy. He leaned against his desk, his whole gross body quivering. His voice came in a terrified bleat.

“Get out! Get out — there’s some mistake — you don’t know—”

“No mistake,” said “X” icily. “You’ve been slated to get it. The boss told me.”

“Oh!” Mottled red spread over Traub’s face now. His voice came thick with fury. “The double-crosser!”

In that one sentence Traub had betrayed himself — and, as his fingers groped frantically for a gun that he kept in his desk drawer, Agent “X” leaped forward.

He dropped the tooth-shaped injector to the carpeted floor. His balled fist lashed out, landed flush on Traub’s jaw. The commissioner’s head snapped back. He staggered against the desk, slid to the floor and lay still, inert as a fallen sack of meal.

Quickly Agent “X” jabbed the point of his anesthetizing hypo needle into the commissioner’s arm. The man would stay out for hours now. Then “X” raised his head and listened.

For seconds he waited tensely, fearing that Traub’s harsh voice had waked some one in the house. But there was no sound. “X” crossed the room quietly and closed the door into the corridor. Then he came back to Traub’s side.

FOR nearly two minutes he studied Traub’s face from every angle. The commissioner had bulbous features, a complexion that was usually ruddy. To a man who was the master of the thousand faces, these characteristics would not be hard to duplicate.

Agent “X” set to work quickly. When he had conserved his plastic material in doctoring up the face of the unconscious gangster back in the hideout, he had not guessed how soon he would have use for it himself. Now he was glad he had conserved it. He pushed back the ape mask hood of his costume.

There was just enough material left in the tube to accomplish what he wanted. He selected one of his small vials of colored pigments, quickly rubbed it over his face, imitating Traub’s natural complexion. Then he remolded his features, giving them the bulbous look of Traub’s. He worked fast, tensely. The gangster was waiting outside. Any instant some one might wake in the house. But he did not rise from Traub’s side until he had put the last, final touches to a make-up that was a masterpiece of creation, considering the short time he had had to work.

Traub was a fatter man than Agent “X.” The Agent, resourceful as always, had already figured out a way to get around that when the time came. His face was now molded into the right, flabby bulbous proportions. It seemed to be the face of Commissioner Traub, rising grotesquely from the hairy gorilla suit.

Before covering his head again with the ape mask hood, Secret Agent “X” crossed quickly to Traub’s desk. He seated himself, lifted the telephone from its hook and called the home of Chief Baxter.

When the chief got on the wire, Agent “X” spoke quickly, but his voice was the thick voice of Traub. For nearly five minutes he talked, uttering words that brought gasps of amazement to Baxter’s lips. Detailed instructions followed, to which Baxter agreed. Then Agent “X” hung up.

He slipped the hood over his head again, left the room and the house as quietly as he had come.

Out on the dark lawn, his gangster colleague greeted him with harsh surliness.

“What the hell took you so long?”

Agent “X” laughed.

“I went through the commish’s desk. Thought maybe I could locate a little extra change. Figured I might as well kill two birds with one stone.”

“Got him then?”

“Yeah. I knocked him out cold first so he wouldn’t squawk.”

“And you got some money, too?”

“Only a little change. Maybe I’ll split with you later if you don’t say nothin’ to the boss.”

“O.K.”

The two figures crept across the lawn. Keeping in the shadows, they moved down the block toward the car that was parked there.

CHIEF BAXTER was tense with excitement. The siren of his special car wailed in the night as he turned into the driveway of the mayor’s house.

The mayor was just getting ready for bed. Baxter’s furious ring at the door brought him downstairs in his bath robe and slippers.

“Chief!” he gasped. “What the—”

Baxter gave the mayor no time for questioning. He spoke hoarsely.

“We’re going to round up that double-damned crook doctor and his gang! We’re going to save this city a million dollars — and we’re going to save our kids.”

“When?”

“Tonight! Traub — don’t ask me how — got on the trail of him! He’s got the goods on the doctor. He don’t know who he is — but he knows where he and his gang are hanging out. They’re in the old gas works down on Canal Street. They’ve got a regular organization. Traub has given me all the dope.”

“Why don’t you go after them then?”

“Not for an hour. Traub’s told me how to get in — but he’s going there first to oil the way. He’s wangled an interview with this crook doctor. There’s a bunch of gangsters there all heeled. There’ll be a fight. We’re going to throw a cordon around the place — an’ we’ve asked some of the troopers to help us. There’s serum there. We’ve got to get that and save the apes, Traub says.”

Chief Baxter paced the floor. He could hardly contain himself. Every few minutes he went to the mayor’s telephone, called up one of his inspectors and bawled orders. Silently along the city’s darkened streets, blue-coated men and men in plain-clothes were assembling. And across the river, in the state troopers’ camp, an officer was issuing abrupt orders. A detachment of armed troops was to be sent into the city, daring the epidemic to catch the fiendish gang behind it. Word was spreading from lip to lip. Men were talking in hushed voices. Baxter left the mayor’s house and sped to headquarters.

It was as though the city were awakening from a deep sleep of hideous dreams. With hope of getting to the bottom of things, stopping the epidemic, and finding a cure at last, the police of Branford were in a frenzy of excitement.

In police radio cruisers, armed headquarters’ cars, and huge emergency trucks mounted with batteries of searchlights, they moved through the city toward Canal Street.

But Baxter ordered silence until the appointed hour came. He was co-operating with Health Commissioner Traub, obeying his instructions. If this raid succeeded tonight, the name of Traub would never be forgotten in Branford. But Chief Baxter was more than glad to share the honors with anyone who could help round up this band of fearful extortionists. Traub, over the phone, had confirmed this belief that the disease had been spread deliberately. Traub said he had secretly been investigating the criminals and had unearthed extraordinary facts.

Chapter XIX

IN the strange, evil hideout of the extortionist ring, Agent “X” was also active. Entering with his gangster colleague, he spoke to the man quickly.

“Let me tell the boss what happened. Here!”

He unfastened the zippers on his fur suit, reached in the back of his coat to a hidden pocket and brought out some bills. These he handed to his companion.

“Some of the change I picked up at Traub’s,” he said. “Give me that injector gadget. You didn’t use it. The boss will want it back.”

The other, impressed by the sight of the money, made no objection. He handed Agent “X” the injector. With both this and his own in his gloved hand, Agent “X” walked back to the room at the end of the corridor, in the wall of which was the boss’s peek-hole.

Agent “X” rapped on the metal partition as he had heard the others do. There was no answer for a second. Momentarily he feared that perhaps the “boss” had gone. Then a sleepy, surly voice answered him. Evidently the leader of the extortionist ring had a cot where he could take naps in the hideout.

“What is it?” His voice came harshly.

“We got Traub, boss. We only had to use one of the gadgets. Here they are.”

“You gave the commissioner a full injection?”

Agent “X” laughed.

“All there was in it, boss.”

The small door below the eyehole opened. A hand appeared.

It was then that Agent “X” acted with the suddenness of a coiled spring abruptly released. He dropped the injectors, seized the hand, held it — pulling it through the opening.

A harsh cry sounded behind the wall. Agent “X” had his needle hypodermic out again. He plunged it into the wrist of the hand he held, squeezed the plunger. Then suddenly he realized that the needle was almost empty. He had used up most of the drug it contained.

But he held the man’s hand tensely till the fingers were beginning to grow lax. The drug was taking effect on the man behind the wall. But how long would he stay unconscious?

Dizziness swept over the Agent. He was aware again of the bacilli in his blood. This it was, he guessed, that had made him forget to fill the hypo needle. But footsteps sounded outside in the corridor. He dropped the hand he held, stepped away from the wall. Two men, evilly costumed and just back from some sinister mission, shuffled into the room.

“We thought we heard some one yell,” growled one.

“I knocked and the boss didn’t answer,” said “X.” “I thought maybe he was asleep and hollered at him. He ain’t there.”

The others rapped also. There was no answer from behind the wall.

“He’ll be back soon,” said one of the men. “He’s stayin’ here nights now.”

They rolled down their hoods, waited, puffing cigarettes. Agent “X” looked at them. Here were more of the vicious scum of the underworld.

They stared at him wondering why he did not make himself comfortable and lower his own mask. He shuffled out of the room, went down the corridor. But two other costumed men passed him. The hideous clan seemed to be assembling — their work for the night over.

AGENT “X” crept down the stairway to the underground garage. Here was the door, the lock of which had given him so much trouble. It was made of steel. It would take the police too much time to open it — and time was precious. He left it unlocked, strode swiftly through the underground passage, unlocking all the doors he came to. Then he ran back, climbed the stairs, and tiptoed into Hornaday’s room.

The man was breathing stertorously again. The effects of the diluted serum had worn off. He was back in the dread coma of sleeping sickness.

Agent “X” rolled up the man’s sleeve and gave him another injection of the serum in the bottle. That would bring Hornaday around by the time—

Feverish impatience possessed the Agent. Shooting pains were stabbing through his head. The disease was progressing in his body. But he was not thinking of himself. He was thinking of the success of his plans, thinking of Betty Dale. The gangsters had taken his watch from him, but he had possessed himself of Traub’s.

He looked at it. Five minutes of two. The night had gone. It was early morning. But these fiends who worked like ghouls in the darkness were still up. So were others, Agent “X” knew, men he had summoned.

He crept resolutely to the head of the stairs again. Faint sounds reached him. Some one was moving along the subterranean passage. The Agent’s heart beat faster.

Then he went to Hornaday’s room again and quickly took off the gorilla-suit. He removed his cloth suit also, stepped back into the furred one again, and put the other over it. This bulked his clothing out, made him look fatter, gave him the proportions of Traub. At places where the black fur came below the cuffs of the other suit, he cut it off. Commissioner Traub seemed to be standing in the room.

A cry sounded somewhere in the passage outside; then it seemed that a series of earthquake shocks came. Through the iron walls, through the concrete of the old gas works, came the blows of axes, the shouts of men. But some of the shouting men were already inside. The corridor outside Hornaday’s room rang suddenly to the sharp reports of automatics. Agent “X” looked out. The place was swarming with police — the men that he had summoned.

Gangsters poured out of the room beyond. Fierce curses sounded, the crack of automatics. A yell went up as one of the gangsters appeared in his hideous gorilla suit. Two cops fired at him point-blank. He fell sprawling grotesquely, his hood came off.

“It ain’t an ape — it’s a man,” cried a cop.

Smoke made the corridor hazy. The acrid tang of it was in the air. Agent “X” ran out into the corridor. He was unarmed, but he didn’t care. The gangsters were putting up a stiff resistance. He saw tear gas bombs in the hands of two cops.

“Not those,” he shouted. “There are real apes here. We can’t take any chance. That gas is liable—”

“Commissioner Traub!”

The cops’ jaws fell. But Chief Baxter shouldered forward, wrung the Agent’s hand.

“Good work, Traub! Great! How the hell did you do it?”

“X” didn’t answer. He snatched up a gun that a gangster, trying to plunge past, and dropped by a cop, had let fall. With this Agent “X” joined the fight. Not often did he use lethal weapons. But time was precious. What if the drug he had administered to the man behind the wall began to lose its effect? The man must not escape. He might take the serum with him — would in all probability.

Agent “X” fought like a fiend; winged two gangsters in the shoulder; pressed forward toward the room at the end of the corridor, until cops gasped at the amazing audacity of Commissioner Traub.

But they followed on his heels. The gangsters made a last stand, and were either shot or taken prisoners.

Then Agent “X” shouted an order.

“Bring in the acetylene torches quickly. Cut through that wall.”

In his telephone conversation with Baxter, talking as Traub, he had instructed that torches be brought. Two big cops from the boiler squad, which had been summoned, came into the room with the gas and torches.

Slipping their goggles over their faces, they set to work. The white-hot flame of the torches bit through the steel wall that separated this chamber from the mystery room beyond.

Sledge hammers broke out the brittle steel in the panels that the torches had cut. Agent “X,” Chief Baxter, and two cops stepped through. Then Baxter gave a harsh cry.

A man was lying on the floor — a man familiar to many citizens of Branford.

“Doctor Roeber!” cried Baxter. “Look, Traub! This guy who took care of the millionaires and swells is the crook, the big shot behind it all.”

FOR one instant only, Agent “X” stood staring. Then his questing eyes searched the room and he leaped forward. In a glass cabinet was the precious serum. In another the dread virus culture, marked in the degrees of its potency. He grabbed one serum syringe, filled it, put it in his pocket. Whatever happened, he would reserve some of that for Betty Dale.

“See that nothing happens to any of this,” he said. “It’s precious. Hornaday’s down the corridor in room G. He’ll tell you what to do. He’ll—”

Agent “X” stopped speaking, for the man on the floor, Doctor Roeber, had suddenly stirred! His face twitched. He roused himself; thrust an arm under him and sat up.

A sudden snarl came to his lips as he saw the faces about him. He rose unsteadily to his feet, but two cops stepped forward and held him.

“We’ve got you, Roeber,” said Chief Baxter harshly. “Caught you with the goods. You’re the devil who stole the apes so you could bleed the people of Branford. But we’ve got you now. Commissioner Traub landed you nicely.”

“Traub!”

The name came from Roeber’s lips like a cry. He turned, saw Agent “X,” and his mouth dropped. Then the blazing light of fury came into his eyes. He raised his hand, spoke with seething venom.

“Traub! He’s the man who worked with me all the time! He’s just trying to save his own dirty skin. He’s in the same boat as I am.”

Eyes turned toward Agent “X.” He waited tensely.

“I can prove it,” said Roeber. “I’ve got letters from him; I know his past! We went into this thing together. He’s the one who found out at the institute what Hornaday was doing.”

Roeber came closer, dragging the cops after him. His sneering, mocking face was close to the Agent’s.

“Deny it if you can, Traub!” he snarled. “You can’t get out of it this way. You thought you could double-cross me, but you can’t. You know about me, but I know about you, too. When you helped me practice in Branford under a fake name after I’d stopped doctoring gangsters; when you introduced me to all the swells and said I was a big society doctor, you didn’t do it for love. I forced you to do it by finding out you were a crooked politician and threatening to expose you. I’ve got pals to prove that. You’re in it up to your neck just as I am.”

The Agent did not attempt to reply. He could not even afford to submit to police investigation. He could see that Roeber’s words had already half convinced Baxter. He was hemmed in on all sides, trapped. And the germs of the sleeping sickness were becoming more and more apparent.

His quick eye roved over the room. Behind Roeber he saw the hidden exit by which Traub and Roeber had been in the habit of entering this room.

As Baxter and Roeber waited breathlessly for him to speak, he suddenly leaped forward, shoving Roeber and the cops who held him out of his way.

He made the exit in two bounds, thrust the door open and went through. Behind him came shouts, the stamping of feet. He fled along a narrow passage, passed through another door and another. The sheer abruptness of his action had given him a start on his pursuers.

THE passage seemed to go on endlessly. It went downward at a slant. Agent “X” knew he was below the level of the earth. Then he climbed a flight of stairs, came at last to a door that opened into a little old shed. The door to this in turn gave into a side street, far from the premises of the old gas works. But the Agent’s pursuers were still on his trail.

He could hear quick-footed cops pounding along the passages that he had traversed. The bacilli of the sleeping sickness made him feel weak. He couldn’t run far. They would overtake him.

He crept away, skirted the gas house, saw an empty police cruiser parked in the street. The cops who had come in it were inside, taking part in the raid.

The Agent leaped into this. Its transmission was not even locked. The law did not suspect that anyone would be bold enough to take a police car.

The first of the pursuing cops came around the corner of the building just in time to see the Agent’s actions. A cry went up. Shots pierced the night. Traub was a marked man now. In the sight of the police, his flight had stamped him as the criminal Roeber claimed him to be.

Agent “X” swung the car away from the curb, headed across the city. Behind him sirens began to wail in the night as the chase was taken up. There had been other cruisers on the block, parked also. The pursuing cops jumped into these.

Clinging to the wheel of the small, jouncing car, half faint with the germs in his body, Agent “X” drove like a fiend. There was the light of purpose in his eye, battling with the glassiness of the disease.

He knew where he was going; knew where he must lead this chase to make it appear right. But at the last he turned and saw two cops on motorcycles catching up. Even the fleet cruiser could not outdistance these two-wheeled speedsters.

He slammed brakes on in front of Commissioner Traub’s house, leaped from the cruiser just as the motorcycles slid to a stop. He bounded toward the house, ran around it. The rear door was still unlocked as he had left it. He thrust it open, stepped back into the shadows, thence to the shrubbery on the lawn.

From this vantage point he saw the cops enter the house — and he wondered with grim humor what they would think when they found Traub unconscious. Suicide would probably be the explanation, until the man awoke from the effects of the harmless drug and faced his accusers.

Agent “X” slipped off into the night, his task done. And in his pocket was the precious syringe of serum that was destined for Betty Dale.

Six hours later the newspapers in a dozen cities were screaming the news that the sleeping sickness epidemic in Branford was being checked. A gigantic extortion racket had been bared. A society doctor, a former gangster surgeon, and the commissioner of health himself were implicated. But now the staff of Drexel Institute, under the direction of a scientist named Hornaday, was rapidly producing the serum that Hornaday had worked out. There would be enough for all in a few days. It was as though a holiday had been declared. Parents with sick children rejoiced. A black pall of horror had been lifted from Branford.

There were two mysteries which the people of Branford could never understand. Why had the guilty Commissioner Traub fled straight back to his home when the police chased him, and why had he apparently anesthetized himself with a harmless drug?

A third mystery, even more puzzling to the newspaper editors of Branford, was how a reporter for an outside paper, the Herald, had gotten hold of the story of the criminals’ capture so long before they were even faintly aware of it. Chief Baxter claimed he had not released the story to anyone. The raid on the gas works had been made in absolute secrecy.

Yet a man, who said he was speaking at the request of Betty Dale, had telephoned the news into the Herald in time to make the early morning edition. He also told them that the eminent Englishman, Doctor Vaughton could be found at a certain address. This created another sensation. It constituted one of the greatest “scoops” in the history of that paper. Their circulation jumped a good fifty-thousand copies and Betty Dale was rewarded with a substantial increase in salary.

Betty, almost well after the injection of serum Agent “X” had given her, could have explained it, but refused to. To do so would have been to go against a promise she had given Secret Agent “X”—a promise not to reveal the amazing, desperate battle he had waged in Branford — now no longer a city of sleeping death.