I + 

Captain Martin Arrowsmith, M.R.C., came home to his good wife Leora, wailing, “I’m so rotten tired, and I feel kind of discouraged. I haven’t accomplished a darn thing in this whole year at McGurk. Sterile. No good. And I’m hanged if I’ll study calculus this evening. Let’s go to the movies. Won’t even change to regular human clothes. Too tired.” + 

“All right, honey,” said Leora. “But let’s have dinner here. I bought a wonderful ole fish this afternoon.” + 

Through the film Martin gave his opinion, as a captain and as a doctor, that it seemed improbable a mother should not know her daughter after an absence of ten years. He was restless and rational, which is not a mood in which to view the cinema. When they came blinking out of that darkness lit only from the shadowy screen, he snorted, “I’m going back to the lab. I’ll put you in a taxi.” + 

“Oh, let the beastly thing go for one night.” + 

“Now that’s unfair! I haven’t worked late for three or four nights now!” + 

“Then take me along.” + 

“Nope. I have a hunch I may be working all night.” + 

Liberty Street, as he raced along it, was sleeping below its towers. It was McGurk’s order that the elevator to the Institute should run all night, and indeed three or four of the twenty staff-members did sometimes use it after respectable hours. + 

That morning Martin had isolated a new strain of staphylococcus bacteria from the gluteal carbuncle of a patient in the Lower Manhattan Hospital, a carbuncle which was healing with unusual rapidity. He had placed a bit of the pus in broth and incubated it. In eight hours a good growth of bacteria had appeared. Before going wearily home he had returned the flask to the incubator. + 

He was not particularly interested in it, and now, in his laboratory, he removed his military blouse, looked down to the lights on the blue-black river, smoked a little, thought what a dog he was not to be gentler to Leora, and damned Bert Tozer and Pickerbaugh and Tubbs and anybody else who was handy to his memory before he absentmindedly wavered to the incubator, and found that the flask, in which there should have been a perceptible cloudy growth, had no longer any signs of bacteria⁠—of staphylococci. + 

“Now what the hell!” he cried. “Why, the broth’s as clear as when I seeded it! Now what the⁠—Think of this fool accident coming up just when I was going to start something new!” + 

He hastened from the incubator, in a closet off the corridor, to his laboratory and, holding the flask under a strong light, made certain that he had seen aright. He fretfully prepared a slide from the flask contents and examined it under the microscope. He discovered nothing but shadows of what had been bacteria: thin outlines, the form still there but the cell substance gone; minute skeletons on an infinitesimal battlefield. + 

He raised his head from the microscope, rubbed his tired eyes, reflectively rubbed his neck⁠—his blouse was off, his collar on the floor, his shirt open at the throat. He considered: + 

“Something funny here. This culture was growing all right, and now it’s committed suicide. Never heard of bugs doing that before. I’ve hit something! What caused it? Some chemical change? Something organic?” + 

Now in Martin Arrowsmith there were no decorative heroisms, no genius for amours, no exotic wit, no edifyingly borne misfortunes. He presented neither picturesque elegance nor a moral message. He was full of hasty faults and of perverse honesty; a young man often unkindly, often impolite. But he had one gift: curiosity whereby he saw nothing as ordinary. Had he been an acceptable hero, like Major Rippleton Holabird, he would have chucked the contents of the flask into the sink, avowed with pretty modesty, “Silly! I’ve made some error!” and gone his ways. But Martin, being Martin, walked prosaically up and down his laboratory, snarling. “Now there was some cause for that, and I’m going to find out what it was.” + 

He did have one romantic notion: he would telephone to Leora and tell her that splendor was happening, and she wasn’t to worry about him. He fumbled down the corridor, lighting matches, trying to find electric switches. + 

At night all halls are haunted. Even in the smirkingly new McGurk Building there had been a bookkeeper who committed suicide. As Martin groped he was shakily conscious of feet padding behind him, of shapes which leered from doorways and insolently vanished, of ancient bodiless horrors, and when he found the switch he rejoiced in the blessing and security of sudden light that recreated the world. + 

At the Institute telephone switchboard he plugged in wherever it seemed reasonable. Once he thought he was talking to Leora, but it proved to be a voice, sexless and intolerant, which said “Number pleeeeeze” with a taut alertness impossible to anyone so indolent as Leora. Once it was a voice which slobbered, “Is this Sarah?” then, “I don’t want you! Ring off, will yuh!” Once a girl pleaded, “Honestly, Billy, I did try to get there but the boss came in at five and he said⁠—” + 

As for the rest it was only a blurring; the sound of seven million people hungry for sleep or love or money. + 

He observed, “Oh, rats, I guess Lee’ll have gone to bed by now,” and felt his way back to the laboratory. + 

A detective, hunting the murderer of bacteria, he stood with his head back, scratching his chin, scratching his memory for like cases of microorganisms committing suicide or being slain without perceptible cause. He rushed upstairs to the library, consulted the American and English authorities and, laboriously, the French and German. He found nothing. + 

He worried lest there might, somehow, have been no living staphylococci in the pus which he had used for seeding the broth⁠—none there to die. At a hectic run, not stopping for lights, bumping corners and sliding on the too-perfect tile floor, he skidded down the stairs and galloped through the corridors to his room. He found the remains of the original pus, made a smear on a glass slide, and stained it with gentian-violet, nervously dribbling out one drop of the gorgeous dye. He sprang to the microscope. As he bent over the brass tube and focused the objective, into the gray-lavender circular field of vision rose to existence the grape-like clusters of staphylococcus germs, purple dots against the blank plane. + 

“Staph in it, all right!” he shouted. + 

Then he forgot Leora, war, night, weariness, success, everything, as he charged into preparations for an experiment, his first great experiment. He paced furiously, rather dizzy. He shook himself into calmness and settled down at a table, among rings and spirals of cigarette smoke, to list on small sheets of paper all the possible causes of suicide in the bacteria⁠—all the questions he had to answer and the experiments which should answer them. + 

It might be that alkali in an improperly cleaned flask had caused the clearing of the culture. It might be some anti-staph substance existing in the pus, or something liberated by the staphylococci themselves. It might be some peculiarity of this particular broth. + 

Each of these had to be tested. + 

He pried open the door of the glass-storeroom, shattering the lock. He took new flasks, cleaned them, plugged them with cotton, and placed them in the hot-air oven to sterilize. He found other batches of broth⁠—as a matter of fact he stole them, from Gottlieb’s private and highly sacred supply in the icebox. He filtered some of the clarified culture through a sterile porcelain filter, and added it to his regular staphylococcus strains. + 

And, perhaps most important of all, he discovered that he was out of cigarettes. + 

Incredulously he slapped each of his pockets, and went the round and slapped them all over again. He looked into his discarded military blouse; had a cheering idea about having seen cigarettes in a drawer; did not find them; and brazenly marched into the room where hung the aprons and jackets of the technicians. Furiously he pilfered pockets, and found a dozen beautiful cigarettes in a wrinkled and flattened paper case. + 

To test each of the four possible causes of the flask’s clearing he prepared and seeded with bacteria a series of flasks under varying conditions, and set them away in the incubator at body temperature. Till the last flask was put away, his hand was steady, his worn face calm. He was above all nervousness, free from all uncertainty, a professional going about his business. + 

By this time it was six o’clock of a fine wide August morning, and as he ceased his swift work, as taut nerves slackened, he looked out of his lofty window and was conscious of the world below: bright roofs, jubilant towers, and a high-decked Sound steamer swaggering up the glossy river. + 

He was completely fagged; he was, like a surgeon after a battle, like a reporter during an earthquake, perhaps a little insane; but sleepy he was not. He cursed the delay involved in the growth of the bacteria, without which he could not discover the effect of the various sorts of broths and bacterial strains, but choked his impatience. + 

He mounted the noisy slate stairway to the lofty world of the roof. He listened at the door of the Institute’s animal house. The guinea pigs, awake and nibbling, were making a sound like that of a wet cloth rubbed on glass in window-cleaning. He stamped his foot, and in fright they broke out in their strange sound of fear, like the cooing of doves. + 

He marched violently up and down, refreshed by the soaring sky, till he was calmed to hunger. Again he went pillaging. He found chocolate belonging to an innocent technician; he even invaded the office of the Director and in the desk of the Diana-like Pearl Robbins unearthed tea and a kettle (as well as a lipstick, and a love-letter beginning “My Little Ickles”). He made himself a profoundly bad cup of tea, then, his whole body dragging, returned to his table to set down elaborately, in a shabby, nearly-filled notebook, every step of his experiment. + 

After seven he worked out the operation of the telephone switchboard and called Lower Manhattan Hospital. Could Dr. Arrowsmith have some more pus from the same carbuncle? What? It’d healed? Curse it! No more of that material. + 

He hesitated over waiting for Gottlieb’s arrival, to tell him of the discovery, but determined to keep silence till he should have determined whether it was an accident. Eyes wide, too wrought up to sleep in the subway, he fled uptown to tell Leora. He had to tell someone! Waves of fear, doubt, certainty, and fear again swept over him; his ears rang and his hands trembled. + 

He rushed up to the flat; he bawled “Lee! Lee!” Before he had unlocked the door. And she was gone. + 

He gaped. The flat breathed emptiness. He searched it again. She had slept there, she had had a cup of coffee, but she had vanished. + 

He was at once worried lest there had been an accident, and furious that she should not have been here at the great hour. Sullenly he made breakfast for himself⁠ ⁠… It is strange that excellent bacteriologists and chemists should scramble eggs so waterily, should make such bitter coffee and be so casual about dirty spoons⁠ ⁠… By the time he had finished the mess he was ready to believe that Leora had left him forever. He quavered, “I’ve neglected her a lot.” Sluggishly, an old man now, he started for the Institute, and at the entrance to the subway he met her. + 

She wailed, “I was so worried! I couldn’t get you on the phone. I went clear down to the Institute to see what’d happened to you.” + 

He kissed her, very competently, and raved, “God, woman, I’ve got it! The real big stuff! I’ve found something, not a chemical you put in I mean, that eats bugs⁠—dissolves ’em⁠—kills ’em. May be a big new step in therapeutics. Oh, no, rats, I don’t suppose it really is. Prob’ly just another of my bulls.” + 

She sought to reassure him but he did not wait. He dashed down to the subway, promising to telephone to her. By ten, he was peering into his incubator. + 

There was a cloudy appearance of bacteria in all the flasks except those in which he had used broth from the original alarming flask. In these, the mysterious murderer of germs had prevented the growth of the new bacteria which he had introduced. + 

“Great stuff,” he said. + 

He returned the flasks to the incubator, recorded his observations, went again to the library, and searched handbooks, bound proceedings of societies, periodicals in three languages. He had acquired a reasonable scientific French and German. It is doubtful whether he could have bought a drink or asked the way to the Kursaal in either language, but he understood the universal Hellenistic scientific jargon, and he pawed through the heavy books, rubbing his eyes, which were filled with salty fire. + 

He remembered that he was an army officer and had lipovaccine to make this morning. He went to work, but he was so twitchy that he ruined the batch, called his patient garçon a fool, and after this injustice sent him out for a pint of whisky. + 

He had to have a confidant. He telephoned to Leora, lunched with her expensively, and asserted, “It still looks as if there were something to it.” He was back in the Institute every hour that afternoon, glancing at his flasks, but between he tramped the streets, creaking with weariness, drinking too much coffee. + 

Every five minutes it came to him, as a quite new and ecstatic idea, “Why don’t I go to sleep?” then he remembered, and groaned, “No, I’ve got to keep going and watch every step. Can’t leave it, or I’ll have to begin all over again. But I’m so sleepy! Why don’t I go to sleep?” + 

He dug down, before six, into a new layer of strength, and at six his examination showed that the flasks containing the original broth still had no growth of bacteria, and the flasks which he had seeded with the original pus had, like the first eccentric flask, after beginning to display a good growth of bacteria cleared up again under the slowly developing attack of the unknown assassin. + 

He sat down, drooping with relief. He had it! He stated in the conclusions of his first notes: + 

“I have observed a principle, which I shall temporarily call the X Principle, in pus from a staphylococcus infection, which checks the growth of several strains of staphylococcus, and which dissolves the staphylococci from the pus in question.” + 

When he had finished, at seven, his head was on his notebook and he was asleep. + 

He awoke at ten, went home, ate like a savage, slept again, and was in the laboratory before dawn. His next rest was an hour that afternoon, sprawled on his laboratory table, with his garçon on guard; the next, a day and a half later, was eight hours in bed, from dawn till noon. + 

But in dreams he was constantly upsetting a rack of test-tubes or breaking a flask. He discovered an X Principle which dissolved chairs, tables, human beings. He went about smearing it on Bert Tozers and Dr. Bissexes and fiendishly watching them vanish, but accidentally he dropped it on Leora and saw her fading, and he woke screaming to find the real Leora’s arms about him, while he sobbed, “Oh, I couldn’t do anything without you! Don’t ever leave me! I do love you so, even if this damned work does keep me tied up. Stay with me!” + 

While she sat by him on the frowsy bed, gay in her gingham, he went to sleep, to wake up three hours later and start off for the Institute, his eyes blood-glaring and set. She was ready for him with strong coffee, waiting on him silently, looking at him proudly, while he waved his arms, babbling: + 

“Gottlieb better not talk any more about the importance of new observations! The X Principle may not just apply to staph. Maybe you can sic it on any bug⁠—cure any germ disease by it. Bug that lives on bugs! Or maybe it’s a chemical principle, an enzyme. Oh, I don’t know. But I will!” + 

As he bustled to the Institute he swelled with the certainty that after years of stumbling he had arrived. He had visions of his name in journals and textbooks; of scientific meetings cheering him. He had been an unknown among the experts of the Institute, and now he pitied all of them. But when he was back at his bench the grandiose aspirations faded and he was the sniffing, snuffling beagle, the impersonal worker. Before him, supreme joy of the investigator, new mountain-passes of work opened, and in him was new power. + 