Microbe Hunters

by Paul De Kruif

  “So Frémy says that yeasts rise by themselves inside the grape!” cried Pasteur. “Well, let him answer this experiment then!” He took a great number of round-bellied flasks and filled them part full of grape juice. He drew each one out into a swan's neck; then he boiled the grape juice in all of them for a few minutes and for days and weeks this grape juice, in every one of all these flasks, showed no bubbles, no yeasts, there was no fermentation in them. Then Pasteur went to a vineyard and gathered a few grapes—they were just ripe—and with a pure water he washed the outsides of them with a clean, heated, badger hairbrush. He put a drop of the wash water under his lens—sure enough!—there were globules, a few wee globes, of yeasts. Then he took ten of his swan neck flasks and ingeniously sealed straight tubes of glass into their sides, and through these straight tubes in each one he put a drop of this wash water from the ripe grapes. Presto! Every one of these ten flasks was filled to the neck in a few days with the pink foam of a good fermentation. There was a little of the wash water left; he boiled that and put drops of this through the straight tubes of ten more flasks. “Just so!” he cried a few days later, “there's no fermentation in these flasks, the boiling has killed the yeasts in the wash water.”

  “Now I shall do the most remarkable experiment of all—I'll prove to this ignorant Frémy that there are no yeasts inside of ripe grapes,” and he took a little hollow tube with a sharp point, sealed shut; it was a little tube he had heated very hot in an oven to kill all life—all yeasts—that might have been in it. Carefully he forced the sharp closed point of the tube through the skin into the middle of the grape; delicately he broke the sealed tip inside the grape—and the little drop of juice that welled up into the tube he transferred with devilish cunning into another swan-necked flask part filled with grape juice. A few days later he cried, “That finishes Frémy—there is no fermentation in this flask at all—there is no yeast inside the grape!” He went on to one of those sweeping statements he loved to make: “Microbes never rise by themselves inside of grapes, or silkworms, or inside of healthy animals—in animal's blood or urine. All microbes have to get in from the outside! That settles Frémy.” Then you can fancy him whispering to himself: “The world will soon learn the miracles that will grow from this little experiment.”

  8

  Surely it looked then as if Pasteur had a right to his fantastic dreams of wiping out disease. He had just received a worshiping letter from the English surgeon Lister—and this letter told of a scheme for cutting up sick people in safety, of doing operations in a way that kept out that deadly mysterious infection that in many hospitals killed eight people out of ten. “Permit me,” wrote Lister, “to thank you cordially for having shown me the truth of the theory of germs of putrefaction by your brilliant researches, and for having given me the single principle which has made the antiseptic system a success. If you ever come to Edinburgh it will be a real recompense to you, I believe, to see in our hospital in how large a measure humanity has profited from your work.”

  Like a boy who has just built a steam engine all by himself Pasteur was proud; he showed the letter to all his friends; he inserted it with all its praise in his scientific papers; he published it—of all places—in his book on beer! Then he took a final smash at poor old Frémy, who you would have thought was already sufficiently crushed by the gorgeous experiments; he smashed Frémy not by damning Frémy, but by praising himself! He spoke of his own “remarkable discoveries,” he called his own theories the true ones and ended: “In a word, the mark of true theories is their fruitfulness. This is the characteristic which Mr. Balard, with an entirely fatherly friendliness, has made stand out in speaking of my researches.” Frémy had no more to say.

  All Europe by now was in a furor about microbes, and he knew it was himself that had changed microbes from playthings into useful helpers of mankind—and perhaps, the world would soon be astounded by it—into dread infinitesimal ogres and murdering marauders, the worst enemies of the race. He had become the first citizen of France and even in Denmark prominent brewers were having his bust put in their laboratories. When suddenly Claude Bernard died, and some of Bernard's friends published this great man's unfinished work. Horrible to tell, this unfinished work had for its subject fermentation of grape juice into wine, and it ended by showing that the whole theory of Pasteur was destroyed because. . . and Bernard closed by giving a series of reasons.

  Pasteur could not believe his eyes. Bernard had done this, the great Bernard who had been his seatmate in the Academy and had always praised his work; Bernard who had exchanged sly sarcastic remarks with him at the Academy of Medicine about those blue-coated pompous brass-buttoned doctors whose talk was keeping real experiment out of medicine. “It's bad enough for these doctors and these half-witted naturalists to contradict me—but truly great men have always appreciated my work—and now Bernard. . . ” you can hear him muttering.

  Pasteur was overwhelmed, but only for a moment. He demanded Bernard's original manuscript. They gave it to him. He studied it with all the close attention in his power. He found Bernard's experiments were only beginnings, rough sketches; gleefully he found that Bernard's friends who had published it had made some discreet changes to make it read better. Then he rose one day, to the scandal of the entire Academy and the shocked horror of all the great men of France, and bitterly scolded Bernard's friends for publishing a research that had dared to question his own theories. Vulgarly he shouted objections at Bernard—who, after all, could not answer Pasteur from his grave. Then he published a pamphlet against his old dead friend's last researches. It was a pamphlet in the worst of taste, accusing Bernard of having lost his memory. That pamphlet even claimed that Bernard, who was to his finger tips a hard man of science, had become tainted with mystical ideas by associating too much with literary lights of the French Academy. It even proved that in his last researches Bernard couldn't see well any more—“I'll wager he had become farsighted and could not see the yeasts!” cried Pasteur. Vulgarly, by all this criticism, he left people to conclude that Bernard had been in his dotage when he did his last work—without any sense of the fitness of things this passionate Pasteur jumped up and down on Bernard's grave.

  Finally he argued with Bernard by beautiful experiments—a thing most other men would have done without making unseemly remarks. Like an American about to build a skyscraper in six weeks he rushed to carpenters and hardware stores and bought huge pieces of expensive glass and with this glass he had the carpenters build ingenious portable hothouses. His assistants worked dinnerless and sleepless, preparing flasks and microscopes and wads of heated cotton; and in an unbelievably short time Pasteur gathered up all this ponderous paraphernalia and hastened to catch a train for his old home in the Jura mountains. Like the so typical misplaced American that he really was, he threw every consideration and all other work to the winds and went directly to the point of settling: “Does my theory of fermentation hold?”

  Coming to his own little vineyard in Arbois, he hastily put up his hothouses around a part of his grape-vines. They were admirable close-fitting hothouses that sealed the grape-vines from the outside air. “It's midsummer, now, the grapes are far from ripe,” he pondered, “and I know that at this time there are never any yeasts to be found on the grapes.” Then, to make doubly sure that no yeasts from the air could fall on the grapes, he carefully wrapped wads of cotton—which his assistants had heated to kill all living beings—around some of the bunches under the glass of the hothouses. He hurried back to Paris and waited nervously for the grapes to ripen. He went back to Arbois too soon in his frantic eagerness to prove that Bernard was wrong—but at last he got there to find them ripe. He examined the hothouse grapes with his microscope; there was not a yeast to be found on their skins. Feverishly he crushed some of them up in carefully heated bottles—not a single bubble of fermentation rose in these flasks—and when he did the same thing to the exposed grapes from the vines outside the hothouse, these bubbled quickly into wine! A
t last he gathered up Madame Pasteur and some of the vines with their cotton-wrapped bunches of grapes—he was going to take these back to the Academy, where he would offer a bunch to each member that wanted one, and he was going to challenge everybody to try to make wine from these protected bunches. . . He knew they couldn't do it without putting yeasts into them. . . He would show them all Bernard was wrong! Madame Pasteur sat stiffly in the train all the way back to Paris, carefully holding the twigs straight up in front of her so that the cotton wrappings wouldn't come undone. It was a whole day's trip to Paris. . .

  Then at the next meeting Pasteur told the Academy of how he had quarantined his grape-vines against yeasts: “Is it not worthy of attention,” he shouted, “that in this vineyard of Arbois, and this would be true of millions of acres of vineyards all over the world, there was at the moment I made these experiments, not a speck of soil which was not capable of fermenting grapes into wine; and is it not remarkable that, on the contrary, the soil of my hothouses could not do this? And why? Because at a definite moment, I covered this soil with some glass. . .”

  Then he jumped to marvelous predictions, prophecies that have since his time come true, he leaped to poetry, I say, that makes you forget his vulgar wrangling with his dead friend Bernard. “Must we not believe, as well, that a day will come when preventive measures that are easy to apply, will arrest those plagues. . . ” and he painted them a lurid picture of the terrible yellow fever that just then had changed the gay streets of New Orleans into a desolation. He made them shiver to hear of the black plague on the far banks of the Volga. Finally he made them hope. . .

  Meanwhile in a little village in Eastern Germany a young stubborn round-headed Prussian doctor was starting on his road to those very miracles that Pasteur was prophesying—this young doctor was doing strange experiments with mice in time stolen from his practice. He was devising ingenious ways to handle microbes so that he could be dead sure he was handling only one kind—he was learning to do a thing that Pasteur with all his brilliant skill had never succeeded in doing. Let us leave Pasteur for a while—even though he is on the threshold of his most exciting experiments and funniest arguments—let us leave him for a chapter and go with Robert Koch, while he is learning to do fantastic, and marvelously important things with those microbes which had been subjects of Pasteur's kingdom for so many years.

  4. KOCH:

  The Death Fighter

  1

  In those astounding and exciting years between 1860 and 1870, when Pasteur was saving vinegar industries and astonishing emperors and finding out what ailed sick silkworms, a small, serious, and nearsighted German was learning to be a doctor at the University of Göttingen. His name was Robert Koch. He was a good student, but while he hacked at cadavers he dreamed of going tiger-hunting in the jungle. Conscientiously he memorized the names of several hundred bones and muscles, but the fancied moan of the whistles of steamers bound for the East chased this Greek and Latin jargon out of his head.

  Koch wanted to be an explorer; or to be a military surgeon and win Iron Crosses; or to be ship's doctor and voyage to impossible places. But alas, when he graduated from the medical college in 1866 he became an interne in a not very interesting insane asylum in Hamburg. Here, busy with raving maniacs and helpless idiots, the echoes of Pasteur's prophecies that there were such things as terrible man-killing microbes hardly reached Koch's ears. He was still listening for steamer-whistles and in the evenings he took walks down by the wharves with Emmy Fraatz; he begged her to marry him; he held out the bait of romantic trips around the world to her. Emmy told Robert that she would marry him, but on condition that he forget this nonsense about an adventurous life, provided that he would settle down to be a practicing doctor, a good useful citizen, in Germany.

  Koch listened to Emmy—for a moment the allure of fifty years of bliss with her chased away his dreams of elephants and Patagonia—and he settled down to practice medicine; he began what was to him a totally uninteresting practice of medicine in a succession of unromantic Prussian villages.

  Just now, while Koch wrote prescriptions and rode horseback through the mud and waited up nights for Prussian farmer women to have their babies, Lister in Scotland was beginning to save the lives of women in childbirth—by keeping microbes away from them. The professors and the students of the medical colleges of Europe were beginning to be excited and to quarrel about Pasteur's theory of malignant microbes, here and there men were trying crude experiments, but Koch was almost as completely cut off from this world of science as old Leeuwenhoek had been, two hundred years before, when he first fumbled at grinding glass into lenses in Delft in Holland. It looked as if his fate was to be the consoling of sick people and the beneficent and praiseworthy attempt to save the lives of dying people—mostly, of course, he did not save them—and his wife Emmy was quite satisfied with this and was proud when Koch earned five dollars and forty-five cents on especially busy days. But Robert Koch was restless. He trekked from one deadly village to another still more uninteresting, until at last he came to Wollstein, in East Prussia, and here, on his twenty-eighth birthday, Mrs. Koch bought him a microscope to play with.

  You can hear the good woman say: “Maybe that will take Robert's mind off what he calls his stupid practice. . . perhaps this will satisfy him a little. . . he's always looking at everything with his old magnifying glass. . .”

  Alas for her, this new microscope, this plaything, took her husband on more curious adventures than any he would have met in Tahiti or Lahore; and these weird experiences—that Pasteur had dreamed of but which no man had ever had before—came on him out of the dead carcasses of sheep and cows. These new sights and adventures jumped at him impossibly on his very doorstep, and in his own drug-reeking office that he was so tired of, that he was beginning to loathe.

  “I hate this bluff that my medical practice is. . . it isn't because I do not want to save babies from diphtheria. . . but mothers come to me crying—asking me to save their babies—and what can I do?—Grope. . . fumble. . . reassure them when I know there is no hope. . . How can I cure diphtheria when I do not even know what causes it, when the wisest doctor in Germany doesn't know?. . . ” So you can imagine Koch complaining bitterly to Emmy, who was irritated and puzzled, and thought that it was a young doctor's business to do as well as he could with the great deal of knowledge that he had got at the medical school—oh! would he never be satisfied?

  But Koch was right. What, indeed, did doctors know about the mysterious causes of disease? Pasteur's experiments were brilliant, but they had proved nothing about the how and why of human sicknesses. Pasteur was a trail-blazer, a fore-runner crying possible future great victories over disease, shouting about magnificent stampings out of epidemics; but meanwhile the moujiks of desolate towns in Russia were still warding off scourges by hitching four widows to a plow and with them drawing a furrow round their villages in the dead of night—and their doctors had no sounder protection to offer them.

  “But the professors, the great doctors in Berlin, Robert, they must know what is the cause of these sicknesses you don't know how to stop.” So Frau Koch might have tried to console him. But in 1873—that is only fifty years ago—I must repeat that the most eminent doctors had not one bit better explanation for the causes of epidemics than the ignorant Russian villagers who hitched the town widows to their plows. In Paris Pasteur was preaching that microbes would soon be found to be the murderers of consumptives: and against this crazy prophet rose the whole corps of the doctors of Paris, headed by the distinguished brass-buttoned Doctor Pidoux.

  “What!” roared this Pidoux, “consumption due to a germ—one definite kind of germ? Nonsense! A fatal thought! Consumption is one and many at the same time. Its conclusion is the necrobiotic and infecting destruction of the plasmatic tissue of an organ by a number of roads that the hygienist and the physician must endeavor to close!” It was so that the doctors fought Pasteur's prophecies with utterly meaningless and often idiotic words.


  2

  Koch was spending his evenings fussing with his new microscope, he was beginning to find out just the right amount of light to shoot up into its lens with the reflecting mirror, he was learning just how needful it was to have his thin glass slides shining clean—those bits of glass on which he liked to put drops of blood from the carcasses of sheep and cows, that had died of anthrax. . .

  Anthrax was a strange disease which was worrying farmers all over Europe, that here and there ruined some prosperous owner of a thousand sheep, that in another place sneaked in and killed the cow—the one support—of a poor widow. There was no rime or reason to the way this plague conducted its maraudings; one day a fat lamb in a flock might be frisking about, that evening this same lamb refused to eat, his head drooped a little—and the next morning the farmer would find him cold and stiff, his blood turned ghastly black. Then the same thing would happen to another lamb, and a sheep, four sheep, six sheep—there was no stopping it. And then the farmer himself, and a shepherd, and a woolsorter, and a dealer in hides might break out in horrible boils—or gasp out their last breaths in a swift pneumonia.

  Koch had started using his microscope with the more or less thorough aimlessness of old Leeuwenhoek; he examined everything under the sun, until he ran on to this blood of sheep and cattle dead of anthrax. Then he began to concentrate, to forget about making a call when he found a dead sheep in a field—he haunted butcher shops to find out about the farms where anthrax was killing the flocks. Koch hadn't the leisure of Leeuwenhoek; he had to snatch moments for his peerings, between prescribing for some child that bawled with a bellyache and the pulling out of a villager's aching tooth. In these interrupted hours he put drops of the blackened blood of a cow dead of anthrax between two thin pieces of glass, very clean shining bits of glass. He looked down the tube of his microscope and among the wee round drifting greenish globules of this blood he saw strange things that looked like little sticks. Sometimes these sticks were short, there might be only a few of them, floating, quivering a little, among the blood globules. But here were others, hooked together without joints—many of them ingeniously glued together till they appeared to him like long threads a thousand times thinner than the finest silk.