The Adaptive Ultimate
by
Stanley G. Weinbaum

Dr. Daniel Scott, his dark and brilliant eyes alight with the fire of enthusiasm, paused at last and stared out over the city, or that portion of it visible from the office windows of Herman Bach—the Dr. Herman Bach of Grand Mercy Hospital. There was a moment of silence; the old man smiled a little indulgently, a little wistfully, at the face of the youthful biochemist.
"Go on, Dan," he said. "So it occurred to you that getting well of a disease or injury is merely a form of adaptation—then what?"
"Then," flashed the other, "I began to look for the most adaptive of living organisms. And what are they? Insects! Insects, of course. Cut off a wing, and it grows back. Cut off a head, stick it to the headless body of another of the same species, and that grows back on. And what's the secret of their great adaptability?"
Dr. Bach shrugged. "What is?"
Scott was suddenly gloomy. "I'm not sure," he muttered. "It's glandular, of course—a matter of hormones." He brightened again. "But I'm off the track. So then I looked around for the most adaptive insect. And which is that?"
"Ants?" suggested Dr. Bach. "Bees? Termites?"
"Bah! They're the most highly evolved, not the most adaptable. No; there's one insect that is known to produce a higher percentage of mutants than any other, more freaks, more biological sports. The one Morgan used in his experiments on the effect of hard X-rays on heredity—the fruit fly, the ordinary fruit fly. Remember? They have reddish eyes, but under X-rays they produced white-eyed offspring—and that was a true mutation, because the white eyes bred true! Acquired characteristics can't be inherited, but these were. Therefore—"
"I know," interrupted Dr. Bach.
Scott caught his breath. "So I used fruit flies," he resumed. "I putrefied their bodies, injected a cow, and got a serum at last, after weeks of clarifying with albumen, evaporating in vacuo, rectifying with— But you're not interested in the technique. I got a serum. I tried it on tubercular guinea pigs, and"—he paused dramatically—"it cured! They adapted themselves to the tubercle bacillus. I tried it on a rabid dog. He adapted. I tried it on a cat with a broken spine. That knit. And now, I'm asking you for the chance to try it on a human being!"
Dr. Bach frowned. "You're not ready," he grunted. "You're not ready by two years. Try it on an anthropoid. Then try it on yourself. I can't risk a human life in an experiment that's as raw as this."
"Yes, but I haven't got anything that needs curing, and as for an anthropoid, you get the board to allow funds to buy an ape—if you can. I've tried."
"Take it up with the Stoneman Foundation, then."
"And have Grand Mercy lose the credit? Listen, Dr. Bach, I'm asking for just one chance—a charity case—anything."
"Charity cases are human beings." The old man scowled down at his hands. "See here, Dan. I shouldn't even offer this much, because it's against all medical ethics, but if I find a hopeless case—utterly hopeless, you understand—where the patient himself consents, I'll do it. And that's the final word."
Scott groaned. "And try to find a case like that. If the patient's conscious, you think there's hope, and if he isn't how can he consent? That settles it!"
But it didn't. Less than a week later Scott looked suddenly up at the annunciator in the corner of his tiny laboratory. "Dr. Scott," it rasped. "Dr. Scott. Dr. Scott. To Dr. Bach's office."
He finished his titration, noted the figures, and hurried out. The old man was pacing the floor nervously as Scott entered.
"I've got your case, Dan," he muttered. "It's against all ethics—yet I'll be damned if I can see how you can do this one any harm. But you'd better hurry. Come on—isolation ward."
They hurried. In the tiny cubical room Scott stared appalled. "A girl!" he muttered.
She could never have been other than drab and plain, but lying there with the pallor of death already on her cheeks, she had an appearance of somber sweetness. Yet that was all the charm she could ever have possessed; her dark, cropped, oily hair was unkempt and stringy, her features flat and unattractive. She breathed with an almost inaudible rasp, and her eyes were dosed.
"Do you," asked Scott, "consider this a test? She's all but dead now."
Dr. Bach nodded. "Tuberculosis," he said, "final stage. Her lungs are hemorrhaging—a matter of hours."
The girl coughed; flecks of blood appeared on her pallid lips. She opened dull, watery blue eyes.
"So!" said Bach, "conscious, eh? This is Dr. Scott. Dan, this is—uh"—he peered at the card at the foot of the bed—"Miss—uh—Kyra Zelas. Dr. Scott has an injection, Miss Zelas. As I warned you, it probably won't help, but I can't see how it can hurt. Are you willing?"
She spoke in faint, gurgling tones. "Sure, I'm through anyway. What's the odds?"
"All right. Got the hypo, Dan?" Bach took the tube of water-clear serum. "Any particular point of injection? No? Give me the cubital, then."
He thrust the needle into the girl's arm. Dan noted that she did not even wince at the bite of the steel point, but lay stoical and passive as thirty cc. of liquid flowed into her veins. She coughed again, then closed her eyes.
"Come out of here," ordered Bach gruffly, as they moved into the hall, "I'm damned if I like this. I feel like a dirty dog."

He seemed to feel less canine, however, the following day. "That Zelas case is still alive," he reported to Scott. "If I dared trust my eyes, I'd say she's improved a little. A very little. I'd still call it hopeless."
But the following day Scott found himself seated in his office with a puzzled expression in his old gray eyes. "Zelas is better," he muttered. "No question of it. But you keep your head, Dan. Such miracles have happened before, and without serums. You wait until we've had her under long observation."
By the end of the week it became evident that the observation was not to be long. Kyra Zelas flourished under their gaze like some swift-blooming tropical weed. Queerly, she lost none of her pallor, but flesh softened the angular features, and a trace of light grew in her eyes.
"The spots on her lungs are going," muttered Bach. "She's stopped coughing, and there's no sign of bugs in her culture. But the queerest thing, Dan—and I can't figure it out, either—is the way she reacts to abrasions and skin punctures. Yesterday I took a blood specimen for a Wasserman, and—this sounds utterly mad—the puncture closed almost before I had a c.c.! Closed and healed!"
And in another week, "Dan, I can't see any reason for keeping Kyra here. She's well. Yet I want her where we can keep her under observation. There's a queer mystery about this serum of yours. And besides, I hate to turn her out to the sort of life that brought her here."
"What did she do?"
"Sewed. Piece work in some sweatshop, when she could work at all. Drab, ugly, uneducated girl, but there's something appealing about her. She adapts quickly."
Scott gave him a strange look. "Yes," he said, "she adapts quickly."
"So," resumed Bach, "it occurred to me that she could stay at my place. We could keep her under observation, you see, and she could help the housekeeper. I'm interested—damn' interested. I think I'll offer her the chance."
Scott was present when Dr. Bach made his suggestion. The girl Kyra smiled. "Sure," she said. Her pallid, plain face lighted up. "Thanks."
Bach gave her the address. "Mrs. Getz will let you in. Don't do anything this afternoon. In fact, it might not hurt you to simply walk in the park for a few hours."
Scott watched the girl as she walked down the hall toward the elevator. She had filled out, but she was still spare to the point of emaciation, and her worn black suit hung on her as if it were on a frame of sticks. As she disappeared, he moved thoughtfully about his duties, and a quarter hour later descended to his laboratory.
On the first floor, turmoil met him. Two officers were carrying in the body of a nondescript old man, whose head was a bloody ruin. There was a babble of excited voices, and he saw a crowd on the steps outside.
"What's up?" he called. "Accident?"
"Accident!" snapped an officer. "Murder, you mean. Woman steps up to this old guy, picks a hefty stone from the park border, slugs him, and takes his wallet. Just like that!"
Scott peered out of the window. The Black Maria was backing toward a crowd on the park side of the street.
A pair of hulking policemen flanked a thin figure in black, thrusting it toward the doors of the vehicle. Scott gasped. It was Kyra Zelas!

A week later Dr. Bach stared into the dark fireplace of his living room. "It's not our business," he repeated. "My God!" blazed Scott. "Not our business! How do we know we're not responsible? How do we know that our injection didn't unsettle her mind? Glands can do that; look at Mongoloid idiots and cretins. Our stuff was glandular. Maybe we drove her crazy!"
"All right," said Bach. "Listen. We'll attend the trial tomorrow, and if it looks bad for her, we'll get hold of her lawyer and let him put us on the stand. We'll testify that she's just been released after a long and dangerous illness, and may not be fully responsible. That's entirely true."
Mid-morning of the next day found them hunched tensely on benches in the crowded courtroom. The prosecution was opening; three witnesses testified to the event.
"This old guy buys peanuts for the pigeons. Yeah, I sell 'em to him every day—or did. So this time he hasn't any change, and he pulls out his wallet, and I see it's stuffed with bills. And one minute later I see the dame pick up the rock and conk him. Then she grabs the dough—"
"Describe her, please."
"She's skinny, and dressed in black. She ain't no beauty, neither. Brownish hair, dark eyes, I don't know whether dark-blue or brown."
"Your witness!" snapped the prosecutor.
A young and nervous individual—appointed by the court, the paper said—rose. "You say," he squeaked, "that the assailant had brown hair and dark eyes?"
"Yeah."
"Will the defendant please rise?"
Her back was toward Scott and Bach as Kyra Zelas arose, but Scott stiffened. Something strangely different about her appearance; surely her worn black suit no longer hung so loosely about her. What he could see of her figure seemed—well, magnificent.
"Take off your hat, Miss Zelas," squeaked the attorney.
Scott gasped. Radiant as aluminum glowed the mass of hair she revealed!
"I submit, your honor, that this defendant does not possess dark hair, nor, if you will observe, dark eyes. It is, I suppose, conceivable that she could somehow have bleached her hair while in custody, and I therefore"—he brandished a pair of scissors—"submit a lock to be tested by any chemist the court appoints. The pigmentation is entirely natural. And as for her eyes—does my esteemed opponent suggest that they, too, are bleached?"
He swung on the gaping witness. "Is this lady the one you claim to have seen committing the crime?"
The man goggled. "Uh—I can't—say."
"Is she?"
"N-no!"
The speaker smiled. "That's all. Will you take the stand, Miss Zelas?"
The girl moved lithe as a panther. Slowly she turned, facing the court. Scott's brain whirled, and his fingers dug into Bach's arm. Silver-eyed, aluminum-haired, alabaster pale, the girl on the stand was beyond doubt the most beautiful woman he had ever seen!
The attorney was speaking again. "Tell the court in your own words what happened, Miss Zelas."
Quite casually the girl crossed her trim ankles and began to speak. Her voice was low, resonant, and thrilling; Scott had to fight to keep his attention on the sense of her words rather than the sound.
"I had just left Grand Mercy Hospital," she said, "where I had been ill for some months. I had crossed the park when suddenly a woman in black rushed at me, thrust an empty wallet into my hands, and vanished. A moment later I was surrounded by a screaming crowd, and—well, that's all."
"An empty wallet, you say?" asked the defense lawyer. "What of the money found in your own bag, which my eminent colleague believes stolen?"
"It was mine," said the girl, "about seven hundred dollars."
Bach hissed, "That's a lie! She had two dollars and thirty-three cents on her when we took her in."
"Do you mean you think she's the same Kyra Zelas we had at the hospital?" gasped Scott.
"I don't know. I don't know anything, but if I ever touch that damned serum of yours—Look! Look, Dan!" This last was a tense whisper.
"What?"
"Her hair! When the sun strikes it!"
Scott peered more closely. A vagrant ray of noon sunlight filtered through a high window, and now and again the swaying of a shade permitted it to touch the metallic radiance of the girl's hair. Scott stared and saw; slightly but unmistakable, whenever the light touched that glowing aureole, her hair darkened from bright aluminum to golden blond!
Something clicked in his brain. There was a clue somewhere—if he could but find it. The pieces of the puzzle were there, but they were woefully hard to fit together. The girl in the hospital and her reaction to incisions; this girl and her reaction to light.
"I've got to see her," he whispered. "There's something I have to find—Listen!"
The speaker was orating. "And we ask the dismissal of the whole case, your honor, on the grounds that the prosecution has utterly failed even to identify the defendant."
The judge's gavel crashed. For a moment his aging eyes rested on the girl with the silver eyes and, incredible hair, then: "Case dismissed!" he snapped. "Jury discharged!"
There was a tumult of voices. Flashlights shot instantaneous sheets of lightning. The girl on the witness stand rose with perfect poise, smiled with lovely, innocent lips, and moved away. Scott waited until she passed close at hand then:
"Miss Zelas!" he called.
She paused. Her strange silver eyes lighted with unmistakable recognition. "Dr. Scott!" said the voice of tinkling metal. "And Dr. Bach!"
She was, then. She was the same girl. This was the drab sloven of the isolation ward, this weirdly beautiful creature of exotic coloring. Staring, Scott could trace now the very identity of her features, but changed as by a miracle.
He pushed through the mob of photographers, press men, and curiosity seekers. "Have you a place to stay?" he asked. "Dr. Bach's offer still stands."
She smiled. "I am very grateful," she murmured, and then, to the crowd of reporters. "The doctor is an old friend of mine." She was completely at ease, unruffled, poised.
Something caught Scott's eye, and he purchased a paper, glancing quickly at the photograph, the one taken at the moment the girl had removed her hat. He started; her hair showed raven black! There was a comment below the picture, too, to the effect that "her striking hair photographs much darker than it appears to the eye."
He frowned. "This way," he said to the girl, then goggled in surprise again. For in the broad light of noon her complexion was no longer the white of alabaster; it was creamy tan, the skin of one exposed to long hours of sunlight; her eyes were deep violet, and her hair—that tiny wisp unconcealed by her hat—was as black as the basalt columns of hell!
Kyra had insisted on stopping to purchase a substitute for the worn black suit, and had ended by acquiring an entire outfit. She sat now curled in the deep davenport before the fireplace in Dr. Bach's library, sheathed in silken black from her white throat to the tiny black pumps on her feet. She was almost unearthly in her weird beauty, with her aluminum hair, silver eyes, and marble-pale skin against the jet silk covering.
She gazed innocently at Scott. "But why shouldn't I?" she asked. "The court returned my money; I can buy what I please with it."
"Your money?" he muttered. "You had less than three dollars when you left the hospital."
"But this is mine now."
"Kyra," he said abruptly, "where did you get that money?"
Her face was saintlike in its purity. "From the old man."
"You—you did murder him!"
"Why, of course I did."
He choked. "My Lord!" he gasped. "Don't you realize we'll have to tell?"
She shook her head, smiling, gently from one to the other of them. "No, Dan. You won't tell, for it wouldn't do any good. I can't be tried twice for the same crime. Not in America."
"But why, Kyra? Why did you—"
"Would you have me resume the life that sent me into your hands? I needed money; money was there; I took it."
"But murder!"
"It was the most direct way."
"Not if you happened to be punished for it," he returned grimly.
"But I wasn't," she reminded him gently.
He groaned. "Kyra," he said, shifting the subject sud-denly, "why do your eyes and skin and hair darken in sunlight or when exposed to flashlight?"
She smiled. "Do they?" she asked. "I hadn't noticed." She yawned, stretched her arms above her head and her slim legs before her. "I think I shall sleep now," she announced. She swept her magnificent eyes over them, rose, and disappeared into the room Dr. Bach had given her—his own.
Scott faced the older man, his features working in emotion. "Do you see?" he hissed. "Good Lord, do you see?"
"Do you, Dan?"
"Part of it. Part of it, anyway."
"And I see part as well."
"Well," said Scott, "here it is as I see it. That serum—that accursed serum of mine—has somehow accentuated this girl's adaptability to an impossible degree. What is it that differentiates life from non-living matter? Two things, irritation and adaptation. Life adapts itself to its environment, and the greater the adaptability, the more successful the organism.
"Now," he proceeded, "all human beings show a very considerable adaptivity. When we expose ourselves to sunlight, our skin shows pigmentation—we tan. That's adaptation to an environment containing sunlight. When a man loses his right hand, he learns to use his left. That's another adaptation. When a person's skin is punctured, it heals and rebuilds, and that's another angle of the same thing. Sunny regions produce dark-skinned, dark-haired people; northern lands produce blonds—and that's adaptation again.
"So what's happened to Kyra Zelas, by some mad twist I don't understand, is that her adaptive powers have been increased to an extreme. She adapts instantly to her environment; when sun strikes her, she tans at once, and in shade she fades immediately. In sunlight her hair and eyes are those of a tropical race; in shadow, those of a Northerner. And—good Lord, I see it now—when she was faced with danger there in the courtroom, faced by a jury and judge who were men, she adapted to that! She met that danger, not only by changed appearance, but by a beauty so great, that she couldn't have been convicted!" He paused. "But how? How?"
"Perhaps medicine can tell how," said Bach. "Undoubtedly man is the creature of his glands. The differences between races—white, red, black, yellow—is doubtless glandular. And perhaps the most effective agent of adaptation is the human brain and neural system, which in itself is controlled partly by a little greasy mass on the floor of the brain's third ventricle, before the cerebellum, and supposed by the ancients to be the seat of the soul.
"I mean, of course, the pineal gland. I suspect that what your serum contains is the long-sought hormone pinealin, and that it has caused hypertrophy of Kyra's pineal gland. And Dan, do you realize that if her adaptability is perfect, she's not only invincible, but invulnerable?"
"That's true!" gulped Scott. "Why, she couldn't be electrocuted, because she'd adapt instantly to an environment containing an electric current, and she couldn't be killed by a shot, because she'd adapt to that as quickly as to your needle pricks. And poison—but there must be a limit somewhere!"
"There doubtless is," observed Bach. "I hardly believe she could adapt herself to an environment containing a fifty-ton locomotive passing over her body. And yet there's an important point we haven't considered. Adaptation itself is of two kinds."
"Two kinds?"
"Yes. One kind is biological; the other, human. Naturally a biochemist like you would deal only with the first, and equally naturally a brain surgeon like me has to consider the second as well. Biological adaptation is what all life—plant, animal, and human—possesses, and it is merely conforming to one's environment. A chameleon, for instance, shows much the same ability as Kyra herself, and so, in lesser degree, does the arctic fox, white in winter, brown in summer; or the snowshoe rabbit, for that matter, or the weasel. All life conforms to its environment to a great extent, because if it doesn't, it dies. But human life does more."
"More?"
"Much more. Human adaptation is not only conformity to environment, but also the actual changing of environment to fit human needs! The first cave man who left his cave to build a grass hut changed his environment, and so, in exactly the same sense, did Steinmetz, Edison, and as far as that goes, Julius Caesar and Napoleon. In fact, Dan, all human invention, genius, and military leadership boils down to that one fact—changing the environment instead of conforming to it."
He paused, then continued, "Now we know that Kyra possesses the biological adaptivity. Her hair and eyes prove that. But what if she possesses the other to the same degree? If she does, God knows what the result will be. We can only watch to see what direction she takes—watch and hope."
"But I don't see," muttered Scott, "how that could be glandular."
"Anything can be glandular. In a mutant—and Kyra's as much a mutant as your white-eyed fruit flies—anything is possible." He frowned reflectively. "If I dared phrase a philosophical interpretation, I'd say that Kyra—perhaps—represents a stage in human evolution. A mutation. If one ventured to believe that, then de Vries and Weissman are justified."
"The mutation theory of evolution, you mean?"
"Exactly. You see, Dan, while it is very obvious from fossil remains that evolution occurred, yet it is very easy to prove it couldn't possibly have occurred!"
"How?"
"Well, it couldn't have occurred slowly, as Darwin believed, for many reasons. Take the eye, for instance. He thought that very gradually, over thousands of generations, some sea creature developed a spot on its skin that was sensitive to light, and that this gave it an advantage over its blind fellows. Therefore its kind survived and others perished. But see here. If this eye developed slowly, why did the very first ones, the ones that couldn't yet see, have any better chance than the others? And take a wing. What good is a wing until you can fly with it? Just because a jumping lizard had a tiny fold of skin between foreleg and breast wouldn't mean that that lizard could survive where others died. What kept the wing developing to a point where it could actually have value?"
"What did?"
"De Vries and Weissman say nothing did. They answer that evolution must have progressed in jumps, so that when the eye appeared, it was already efficient enough to have survival value, and likewise the wing. Those jumps they named mutations. And in that sense, Dan, Kyra's a mutation, a jump from the human to—something else. Perhaps the superhuman."
Scott shook his head in perplexity. He was thoroughly puzzled, completely baffled, and more than a little unnerved. In a few moments more he bade Bach good night, wandered home, and lay for hours in sleepless thought.
The next day Bach managed a leave of absence for both of them from Grand Mercy, and Scott moved in. This was in part simply out of his fascinated interest in the case of Kyra Zelas, but in part it was altruistic. She had confessedly murdered one man; it occurred to Scott that she might with no more compunction murder Dr. Bach, and he meant to be at hand to prevent it.
He had been in her company no more than a few hours before Bach's words on evolution and mutations took on new meaning. It was not only Kyra's chameleon-like coloring, nor her strangely pure and saintlike features, nor even her incredible beauty. There was something more; he could not at once identify it, but decidedly the girl Kyra was not quite human.
The event that impressed this on him occurred in the late afternoon. Bach was away somewhere on personal business, and Scott had been questioning the girl about her own impressions of her experience.
"But don't you know you've changed?" he asked. "Can't you see the difference in yourself?"
"Not I. It is the world that has changed."
"But your hair was black. Now it's light as ashes."
"Was it?" she asked. "Is it?"
He groaned in exasperation. "Kyra," he said, "you must know something about yourself."
Her exquisite eyes turned their silver on him. "I do," she said. "I know that what I want is mine, and"—her pure lips smiled—"I think I want you, Dan."
It seemed to him, that she changed at that moment. Her beauty was not quite as it had been, but somehow more wildly intoxicating than before. He realized what it meant; her environment now contained a man she loved, or thought she loved, and she was adapting to that, too. She was becoming—he shivered slightly—irresistible!
Bach must have realized the situation, but he said nothing. As for Scott, it was sheer torture, for he realized only too well that the girl he loved was a freak, a biological sport, and worse than that, a cold murderess and a creature not exactly human. Yet for the next several days things went smoothly. Kyra slipped easily into the routine; she was ever a willing subject for their inquiries and investigations.
Then Scott had an idea. He produced one of the guinea pigs that he had injected, and they found that the creature evinced the same reaction as Kyra to cuts. They killed the thing by literally cutting it in half with an ax, and Bach examined its brain.
"Right!" he said at last. "It's hypertrophy of the pineal." He stared intently at Scott. "Suppose," he said, "that we could reach Kyra's pineal and correct the hypertrophy. Do you suppose that might return her to normal?"
Scott suppressed a pang of fear. "But why? She can't do any harm as long as we guard her here. Why do we have to gamble with her life like that?"
Bach laughed shortly. "For the first time in my life I'm glad I'm an old man," he said. "Don't you see we have to do something? She's a menace. She's dangerous. Heaven only knows how dangerous. We'll have to try."
Scott groaned and assented. An hour later, under the pretext of experiment, he watched the old man inject five grains of morphia into the girl's arm, watched her frown and blink—and adjust. The drug was powerless.
It was at night that Bach got his next idea. "Ethyl chloride!" he whispered. "The instantaneous anaesthetic. Perhaps she can't adjust to lack of oxygen. We'll try."
Kyra was asleep. Silently, carefully, the two crept in, and Scott stared down in utter fascination at the weird beauty of her features, paler than ever in the faint light of midnight. Carefully, so carefully, Bach held the cone above her sleeping face, drop by drop he poured the volatile, sweet-scented liquid into it. Minutes passed.
"That should anaesthetize an elephant," he whispered at last, and jammed the cone full upon her face.
She awoke. Fingers like slim steel rods closed on his wrist, forcing his hand away. Scott seized the cone, and her hand clutched his wrist as well, and he felt the strength of her grasp.
"Stupid," she said quietly, sitting erect. "This is quite useless—look!"
She snatched a paper knife from the table beside the bed. She bared her pale throat to the moonlight, and then, suddenly, drove the knife to its hilt into her bosom!
Scott gulped in horror as she withdrew it. A single spot of blood showed on her flesh, she wiped it away, and displayed her skin, pale, unscarred, beautiful.
"Go away," she said softly, and they departed.
The next day she made no reference to the incident. Scott and Bach spent a worried morning in the laboratory, doing no work, but simply talking. It was a mistake, for when they returned to the library, she was gone, having, according to Mrs. Getz, simply strolled out of the door and away. A hectic and hasty search of the adjacent blocks brought no sign of her.
At dusk she was back, pausing hatless in the doorway to permit Scott, who was there alone, to watch the miraculous change as she passed from sunset to chamber, and her hair faded from mahogany to aluminum.
"Hello," she said smiling. "I killed a child."
"What? My Lord, Kyra!"
"It was an accident. Surely you don't feel that I should be punished for an accident, Dan, do you?"
He was staring in utter horror. "How—"
"Oh, I decided to walk a bit. After a block or two, it occurred to me that I should like to ride. There was a car parked there with the keys in it, and the driver was talking on the sidewalk, so I slipped in, started it, and drove away. Naturally I drove rather fast, since he was shouting, and at the second corner I hit a little boy."
"And—you didn't stop?"
"Of course not. I drove around the corner, turned another corner or two, and then parked the car and walked back. The boy was gone, but the crowd was still there. Not one of them noticed me." She smiled her saintlike smile. "We're quite safe. They can't possibly trace me."
Scott dropped his head on his hands and groaned. "I don't know what to do!" he muttered. "Kyra, you're going to have to report this to the police."
"But it was an accident," she said gently, her luminous silver eyes pityingly on Scott.
"No matter. You'll have to."
She placed her white hand on his head. "Perhaps tomorrow," she said. "Dan, I have learned something. What one needs in this world is power. As long as there are people in the world with more power than I, I run afoul of them. They keep trying to punish me with their laws—and why? Their laws are not for me. They cannot punish me."
He did not answer.
"Therefore," she said softly, "tomorrow I go out of here to seek power. I will be more powerful than any laws."
That shocked him to action. "Kyra!" he cried. "You're not to try to leave here again." He gripped her shoulders. "Promise me! Swear that you'll not step beyond that door without me!"
"Why, if you wish," she said quietly.
"But swear it! Swear it by everything sacred!"
Her silver eyes looked steadily into his from a face like that of a marble angel. "I swear it," she murmured. "By anything you name, I swear it, Dan."
And in the morning she was gone, taking what cash and bills had been in Scott's wallet, and in Bach's as well. And, they discovered later, in Mrs. Getz's also.
"But if you could have seen her!" muttered Scott. "She looked straight into my eyes and promised, and her face was pure as a madonna's. I can't believe she was lying."
"The lie as an adaptive mechanism," said Bach, "deserves more attention than it has received. Probably the original liars are those plants and animals that use protective mimicry—harmless snakes imitating poisonous ones, stingless flies that look like bees. Those are living lies."
"But she couldn't—"
"She has, however. What you've told me about her desire for power is proof enough. She's entered the second adaptive phase—that of adapting her environment to herself instead of herself to her environment. How far will her madness—or her genius—carry her? There is very little difference between the two, Dan. And what is left now for us to do but watch?"
"Watch? How? Where is she?"
"Unless I'm badly mistaken, watching her will be easy once she begins to achieve. Wherever she is, I think we—and the rest of the world—will know of it soon enough."

But weeks dropped away without sign of Kyra Zelas. Scott and Bach returned to their duties at Grand Mercy, and down in his laboratory the biochemist disposed grimly of the remains of three guinea pigs, a cat, and a dog, whose killing had been an exhausting and sickening task. In the crematory as well went a tube of water-clear serum.
Then one day the annunciator summoned him to Bach's office, where he found the old man hunched over a copy of the Post Record.
"Look here!" he said, indicating a political gossip column called "Whirls of Washington."
Scott read, "And the surprise of the evening was the soidisant confirmed bachelor of the cabinet, upright John Callan, who fluttered none other than the gorgeous Kyra Zelas, the lady who affects a dark wig by day and a white by night. Some of us remember her as the acquittee of a murder trial."
Scott looked up. "Callan, eh? Secretary of the treasury, no less! When she said power she meant power, apparently."
"But will she stop there?" mused Bach gloomily. "I have a premonition that she's just beginning."
"Well, actually, how far can a woman go?"
The old man looked at him. "A woman? This is Kyra Zelas, Dan. Don't set your limits yet. There will be more of her."
Bach was right. Her name began to appear with increasing frequency, first in social connections, then with veiled references to secret intrigues and influences.
Thus: "Whom do the press boys mean by the tenth cabineteer?" Or later: "Why not a secretary of personal relations? She has the powers; give her the name." And still later: "One has to go back to Egypt for another instance of a country whose exchequer was run by a woman. And Cleopatra busted that one."
Scott grinned a little ruefully to himself as he realized that the thrusts were becoming more indirect, as if the press itself were beginning to grow cautious. It was a sign of increasing power, for nowhere are people as sensitive to such trends as among the Washington correspondents. Kyra's appearance in the public prints began to be more largely restrained to purely social affairs, and usually in connection with John Callan, the forty-five-year-old bachelor secretary of the treasury.
Waking or sleeping, Scott never for a moment quite forgot her, for there was something mystical about her, whether she were mad or a woman of genius, whether freak or superwoman. The only thing he did forget was a thin girl with drab features and greasy black hair who had lain on a pallet in the isolation ward and coughed up flecks of blood.

It was no surprise to either Scott or Dr. Bach to return one evening to Bach's residence for a few hours' conversation, and find there, seated as comfortably as if she had never left it, Kyra Zelas. Outwardly she had changed but little; Scott gazed once more in fascination on her incredible hair and wide, innocent silver eyes. She was smoking a cigarette, and she exhaled a long, blue plume of smoke and smiled up at him.
He hardened himself. "Nice of you to honor us," he said coldly. "What's the reason for this visit? Did you run out of money?"
"Money? Of course not. How could I run out of money?"
"You couldn't, not as long as you replenished your funds the way you did when you left."
"Oh, that!" she said contemptuously. She opened her hand bag, indicating a green mass of bills. "I'll give that back, Dan. How much was it?"
"To hell with the money!" he blazed. "What hurts me is the way you lied. Staring into my eyes as innocent as a baby, and lying all the time!"
"Was I?" she asked. "I won't lie to you again, Dan. I promise."
"I don't believe you," he said bitterly. "Tell us what you're doing here, then."
"I wanted to see you. I haven't forgotten what I said to you, Dan." With the words she seemed to grow more beautiful than ever, and this time poignantly wistful as well.
"And have you," asked Bach suddenly, "abandoned your idea of power?"
"Why should I want power?" she rejoined innocently, flashing her magnificent eyes to him.
"But you said," began Scott impatiently, "that you—"
"Did I?" There was a ghost of a smile on her perfect lips. "I won't lie to you, Dan," she went on, laughing a little. "If I want power, it is mine for the taking—more power than you dream."
"Through John Callan?" he rasped.
"He offers a simple way," she said impassively. "Suppose, for instance, that in a day or so he were to issue a statement—a supremely insulting statement—about the war debts. The administration couldn't afford to reprimand him openly, because most of the voters feel that a supremely insulting statement is called for. And if it were insulting enough—and I assure you it would be—you would see the animosity of Europe directed westward.
"Now, if the statement were one that no national government could ignore and yet keep its dignity in the eyes of its people, it would provoke counter-insults. And there are three nations—you know their names as well as I—who await only such a diversion of interest. Don't you see?" She frowned.
"How stupid you both are!" she murmured, and then, stretching her glorious figure and yawning, "I wonder what sort of empress I would make. A good one, doubtless."
But Scott was aghast. "Kyra, do you mean you'd urge Callan into such a colossal blunder as that?"
"Urge him!" she echoed contemptuously. "I'd force him."
"Do you mean you'd do it?"
"I haven't said so," she smiled. She yawned again, and snapped her cigarette into the dark fireplace. "I'll stay here a day or two," she added pleasantly, rising. "Good night."
Scott faced Dr. Bach as she vanished into the old man's chamber. "Damn her!" he grated, his lips white. "If I believed she meant all of that—"
"You'd better believe it," said Bach.
"Empress, eh! Empress of what?"
"Of the world, perhaps. You can't set limits to madness or genius."
"We've got to stop her!"
"How? We can't keep her locked up here. In the first place, she'd doubtless develop strength enough in her wrists to break the locks on the doors, and if she didn't, all she'd need to do is shout for help from a window."
"We can have her adjudged insane!" flared Scott. "We can have her locked up where she can't break out or call for help."
"Yes, we could. We could if we could get her committed by the Sanity Commission. And if we got her before them, what chance do you think we'd have?"
"All right, then," said Scott grimly, "we're going to have to find her weakness. Her adaptability can't be infinite. She's immune to drugs and immune to wounds, but she can't be above the fundamental laws of biology. What we have to do is to find the law we need."
"You find it then," said Bach gloomily.
"But we've got to do something. At least we can warn people—" He broke off, realizing the utter absurdity of the idea.
"Warn people!" scoffed Bach. "Against what? We'd be the ones to go before the Sanity Commission then. Callan would ignore us with dignity, and Kyra would laugh her pretty little laugh of contempt, and that would be that."
Scott shrugged helpleessly. "I'm staying here to-night," he said. "At least we can talk to her again tomorrow."
"If she's still here," remarked Bach ironically.
But she was. She came out as Scott was reading the morning papers alone in the library, and sat silently opposite him, garbed in black silk lounging pajamas against which her alabaster skin and incredible hair glowed in startling contrast. He watched skin and hair turn faintly golden as the morning sun lightened the chamber. Somehow it angered him that she should be so beautiful and at the same time deadly with an inhuman deadliness.
He spoke first. "You haven't committed any murders since our last meeting, I hope." He said it spitefully, viciously.
She was quite indifferent. "Why should I? It has not been necessary."
"You know, Kyra," he said evenly, "that you ought to be killed."
"But not by you, Dan. You love me."
He said nothing. The fact was too obvious to deny.
"Dan," she said softly, "if you only had my courage, there is no height we might not reach together. No height—if you had the courage to try. That is why I came back here, but—" She shrugged. "I go back to Washington tomorrow."
Later in the day Scott got Bach alone. "She's going tomorrow!" he said tensely. "Whatever we can do has to be done to-night."
The old man gestured helplessly. "What can we do? Can you think of any law that limits adaptability?"
"No, but—" He paused suddenly. "By Heaven!" he cried. "I can! I've got it!"
"What?"
"The law! A fundamental biological law that must be Kyra's weakness!"
"But what?"
"This! No organism can live in its own waste products! Its own waste is poison to any living thing!"
"But—"
"Listen. Carbon dioxide is a human waste product. Kyra can't adapt to an atmosphere of carbon dioxide!"
Bach stared. "By Heaven!" he cried. "But even if you're right, how—"
"Wait a minute. You can get a couple of cylinders of carbonic acid gas from Grand Mercy. Can you think of any way of getting the gas into her room?"
"Why—this is an old house. There's a hole from her room to the one I'm using, where the radiator connection goes through. It's not tight; we could get a rubber tube past the pipe."
"Good!"
"But the windows! She'll have the windows open." "Never mind that," said Scott. "See that they're soaped so they'll close easily, that's all."
"But even if it works, what good—Dan! You don't mean to kill her?"
He shook his head. "I—couldn't," he whispered. "But once she's helpless, once she's overcome—if she is—you'll operate. That operation on the pineal you suggested before. And may Heaven forgive me!"

Scott suffered the tortures of the damned that evening. Kyra was, if possible, lovelier than ever, and for the first time she seemed to exert herself to be charming. Her conversation was literally brilliant; she sparkled, and over and over Scott found himself so fascinated that the thought of the treachery he planned was an excruciating pain. It seemed almost a blasphemy to attempt violence against one whose outward appearance was so pure, so innocent, so saintlike.
"But she isn't quite—human!" he told himself. "She's not an angel but a female demon, a—what were they called?—an incubus!"
Despite himself, when at last Kyra yawned luxuriously and dropped her dainty feet to the floor to depart, he pleaded for a few moments more.
"But it's early," he said, "and tomorrow you leave."
"I will return, Dan. This is not the end for us."
"I hope not," he muttered miserably, watching the door of her room as it clicked shut.
He gazed at Bach. The older man, after a moment's silence, whispered, "It is likely that she sleeps almost at once. That's also a matter of adaptability."
In tense silence they watched the thin line of light below the closed door. Scott started violently when, after a brief interval, her shadow crossed it and it disappeared with a faint click.
"Now, then," he said grimly. "Let's get it over."
He followed Bach into the adjacent room. There, cold and metallic, stood the gray cylinders of compressed gas. He watched as the old man attached a length of tubing, ran it to the opening around the steam pipe, and began to pack the remaining space with wet cotton.
Scott turned to his own task. He moved quietly into the library. With utmost stealth he tried the door of Kyra's room; it was unlocked as he had known it would be, for the girl was supremely confident of her own invulnerability.
For a long moment he gazed across at the mass of radiant silver hair on her pillow, then, very cautiously, he placed a tiny candle on the chair by the window, so that it should be at about the level of the bed, lighted it with a snap of his cigarette lighter, withdrew the door key, and departed.
He locked the door on the outside, and set about stuffing the crack below it with cotton. It was far from airtight, but that mattered little, he mused, since one had to allow for the escape of the replaced atmosphere.
He returned to Bach's room. "Give me a minute," he whispered. "Then turn it on."
He stepped to a window. Outside was a two-foot ledge of stone, and he crept to this precarious perch. He was visible from the street below, but not markedly noticeable, for he was directly above an areaway between Bach's house and its neighbor. He prayed fervently that he might escape attention.
He crept along the ledge. The two windows of Kyra's chamber were wide, but Bach had done his work. They slid downward, without a creak, and he pressed close against the glass to peer in.
Across the room glowed the faint and steady flame of his little taper. Close beside him, within a short arm's length had no pane intervened, lay Kyra, quite visible in the dusk. She lay on her back, with one arm thrown above her unbelievable hair, and she had drawn only a single sheet over her. He could watch her breathing, quiet, calm, peaceful.
It seemed as if a long time passed. He fancied at last that he could hear the gentle hiss of gas from Bach's window, but he knew that that must be fancy. In the chamber he watched there was no sign of anything unusual; the glorious Kyra slept as she did everything else—easily, quietly, and confidently.
Then there was a sign. The little candle flame, burning steadily in the draughtless air, flickered suddenly. He watched it, certain now that its color was changing. Again it flickered, flared for a moment, then died. A red spark glowed on the wick for a bare instant, then that was gone.
The candle flame was smothered. That meant a concentration of eight or ten per cent of carbon dioxide in the room's temperature—far too high to support ordinary life. Yet Kyra was living. Except that her quiet breathing seemed to have deepened, she gave not even a sign of inconvenience. She had adapted to the decreased oxygen supply.
But there must be limits to her powers. He blinked into the darkness. Surely—surely her breathing was quickening. He was positive now; her breast rose and fell in convulsive gasps, and somewhere in his turbulent mind the scientist in him recorded the fact.
"Cheyne-Stokes breathing," he muttered. In a moment the violence of it would waken her.
It did. Suddenly the silver eyes started open. She brushed her hand across her mouth, then clutched at her throat. Aware instantly of danger, she thrust herself erect, and her bare legs flashed as she pushed herself from the bed. But she must have been dazed, for she turned first to the door.
He saw the unsteadiness in her movements. She twisted the doorknob, tugged frantically, then whirled toward the window. He could see her swaying as she staggered through the vitiated air, but she reached it. Her face was close to his, but he doubted if she saw him, for her eyes were wide and frightened, and her mouth and throat were straining violently for breath. She raised her hand to smash the pane; the blow landed, but weakly, and the window shook but did not shatter.
Again her arm rose, but that blow was never delivered. For a moment she stood poised, swaying slowly, then her magnificent eyes misted and closed, she dropped to her knees, and at last collapsed limply on the floor.
Scott waited a long, torturing moment, then thrust up the window. The rush of lifeless air sent him whirling dizzily on his dangerous perch, and he clutched the casement. Then a slow breeze moved between the buildings, and his head cleared.
He stepped gingerly into the chamber. It was stifling, but near the open window he could breathe. He kicked thrice against Bach's wall.
The hiss of gas ceased. He gathered Kyra's form in his arms, waited until he heard the key turn, then dashed across the room and into the library.
Bach stared as if fascinated at the pure features of the girl. "A goddess overcome," he said. "There is something sinful about our part in this."
"Be quickl" snapped Scott. "She's unconscious, not anaesthetized. God knows how quickly she'll readjust."
But she had not yet recovered when Scott laid her on the operating table in Bach's office, and drew the straps about her arms and body and slim bare legs. He looked down on her still, white face and bright hair, and he felt his heart contract with pain to see them darken ever so faintly and beautifully under the brilliant operating light, rich in actinic rays.
"You were right," he whispered to the unhearing girl. "Had I your courage there is nothing we might not have attained together."
Bach spoke brusquely. "Nasal?" he asked. "Or shall I trephine her?"
"Nasal."
"But I should like a chance to observe the pineal gland. This case is unique, and—"
"Nasal!" blazed Scott. "I won't have her scarred!"
Bach sighed and began. Scott, despite his long hospital experience, found himself quite unable to watch this operation; he passed the old man his instruments as needed, but kept his eyes averted from the girl's passive and lovely face.
"So!" said Bach at last. "It is done." For the first time he himself had a moment's leisure to survey Kyra's features.
Bach started violently. Gone was the exquisite aluminum hair, replaced by the stringy, dark, and oily locks of the girl in the hospital! He pried open her eye, silver no longer, but pallid blue. Of all her loveliness, there remained—what? A trace, perhaps; a trace in the saintlike purity of her pale face, and in the molding of her features. But a flame had died; she was a goddess no longer, but a mortal—a human being. The superwoman had become no more than a suffering girl.
An ejaculation had almost burst from his lips when Scott's voice stopped him.
"How beautiful she is!" he whispered. Bach stared. He realized suddenly that Scott was not seeing her as she was, but as she once had been. To his eyes, colored by love, she was still Kyra the magnificent.
THE END