by Thomas Goetz
On the afternoon of June 2, Pasteur returned to the farm. As his carriage crested a nearby hill, he observed the field scattered with the corpses of dead livestock. At first he couldn’t tell which animals—the infected or the inoculated—were lying dead. But when the crowd recognized him and broke out in cheers, he raised his arms in triumph. “Here it is!” he cried. “Oh ye of little faith!”
The news of Pasteur’s anthrax vaccine itself spread like a virus throughout Europe. Fortuitously, a correspondent from the London Times had witnessed the experiment, as had others from several agricultural journals. Their reports didn’t dabble with the science; they cut to the chase with the ignorant enthusiasm of journalists: Pasteur had triumphed. He had found a vaccine for the horrible scourge anthrax.
Pasteur was elated, and for good reason. He had created the first vaccine in nearly a century, and along the way had crafted a process that connected the diagnostic value of the germ theory with a far more practical preventive purpose. As he described it at a scientific meeting in Paris a few months later, “We now possess a vaccine of anthrax which is capable of saving animals from this fatal disease; a virus vaccine that is itself never lethal; a live vaccine, one that can be cultivated at will and transported without alteration.”
This was no mere scientific discovery; this was something that would save lives—not just of animals, but perhaps of people, too. If he was a celebrated scientist before, he was a champion of the people now. He had matched Jenner and, by pure brilliant sleuthing, found a way to destroy a disease before it could destroy a flock, or a town, or a country.
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ON JULY 31, 1881, WITH THE TRIUMPH OF POUILLY-LE-FORT spreading through Europe, Pasteur crossed the English Channel bound for London. His destination was St. James’s Palace and the Seventh International Medical Congress.
Though there had been previous grand meetings on medicine, this seventh congress promised something of historical proportion. It seemed perfectly timed to capture a new passion for the potential of science. The British Medical Journal, its hometown pride evident, was effusive:
It is always possible to exaggerate the greatness of events, as it is of monuments, to which we are in too close a proximity. . . . The mere fact of the meeting together in such unprecedented numbers of the leading powers engaged in the study and practice of medicine and the pursuit of collateral scientific work, has been a circumstance of which the influence in the future cannot but be long and deeply felt, and of which the present results are as interesting as they have been delightful.
More than three thousand scientists attended from seventy countries—from “every land in which scientific medicine is practiced,” as The Lancet described it. The delegates were entertained as if they were dignitaries, feted by London’s most prominent citizens, including the lord mayor of London and the Baroness Burdett-Coutts. Pasteur was there, to discuss his spectacular work on the anthrax vaccine, as was Koch, who spoke about some remarkable laboratory techniques he’d developed at his new quarters in Berlin. Virchow was in attendance, as was Lister, and William Osler, the Canadian physician who would go on to cofound Johns Hopkins School of Medicine. The congress served as a political stage as well. The Prince of Wales gaveled the first session open, and the crown prince of Russia made an appearance. (The germophobe Pasteur, to his chagrin, found himself obliged to shake hands with the prince.)
Pasteur’s work on an anthrax vaccine was the big news, and he was clearly the man of the hour. When he was introduced in the immense hall, cheers rang out “not once only,” described a report in The Popular Science Monthly, “but again and again, [for] the scientific veteran whose renown has spread from his quiet Parisian laboratory over the whole civilized world.”
The enthusiasm in London was more than just scholarly. Medical sciences were fast becoming essential economic tools, partly to address the needs of Europe’s crowded cities and also as a necessity for overseas colonization and empire building. As countries raced to exploit their holdings in Africa and Asia, they were confronting infectious diseases such as malaria, cholera, and sleeping sickness, illnesses that threatened both indigenous populations and the new European colonialists.
The medical congress offered an essential forum where the germ theory could be discussed and debated. The agenda, accordingly, was filled with bacteriological demonstrations and lectures. This was due largely to Lister’s efforts—he had made sure that both Pasteur and Koch were in attendance. Lister was an unabashed enthusiast for the germ theory and its potential for medicine. Just a year earlier he had suggested, presciently, that “an appropriate ‘vaccine’ may be discovered for measles, scarlet fever, and other acute specific diseases in the human subject.” And being neither French nor German, he was free to admire Koch’s work as well as Pasteur’s.
It turned out, in fact, that Lister had been following Koch’s research closely since the latter’s anthrax paper in 1876; in an address to the British Medical Association in August 1880 he had praised Koch’s inspired work on anthrax and infections. “Though a hard worked general practitioner, Koch has contrived to devote an immense amount of time and energy to his investigations,” Lister said. “He has succeeded in demonstrating the presence of these minute organisms in a manner never before attained.”
Though Pasteur had the spotlight at the 1881 medical congress, Koch had been making his own advances in recent months (albeit of a much less theatrical variety). In particular, he had been improving his laboratory techniques, methods that would help make the germ theory more-accepted science. Koch demonstrated his advances in Lister’s lab during the medical congress, and crowds packed in tight around Koch’s tables and instruments. First, Koch showed his microphotography tools, explaining how he had refined the lens and isolated the bacteria in photographs. Then he turned to his latest breakthrough: a new technique for culturing bacteria. Traditionally, bacteriologists worked with liquid organic materials such as milk or, in Koch’s ingenious case, the optical fluid from inside a cow’s eye. Bacteria flourished in these environments, but liquid was a difficult medium to work with. The microbes moved about in the fluid and could be impossible to isolate, making it difficult to measure their growth.
He had noticed, though, that bacteria and molds readily grew upon a cooked potato—and that, moreover, they would grow outward from their point of origin. This made it far easier to isolate the microbes and accurately measure them. But germ cultures grew inconsistently on potato slices, keeping Koch on the lookout. He soon discovered that gelatin was much more promising, especially since it could be poured evenly on a glass plate.
The advance here was purely technical; it offered a better method for pursuing science. But this makes his breakthrough no less significant. The paper Koch published explaining his work, which he blandly titled “Methods for the Study of Pathogenic Organisms,” is still referred to today as the bible of bacteriology. As with his work on microphotographs and on wound infections, the methods he detailed in the paper gave the germ theory a scientific rigor and a process that it had lacked previously.
Demonstrating these techniques in Lister’s lab in London, Koch displayed a distinct lack of showmanship. Keeping his head down and speaking almost in a mumble, he quietly explained his methods, his manner the antithesis of Pasteur’s razzle-dazzle performances. To those not paying close attention, his presentation would have seemed a mundane recitation of banal laboratory procedures. But his demeanor was deceptive. With each gesture, each tool, Koch was pushing science forward and giving other scientists a platform for further progress. Among those in the audience was Louis Pasteur, who couldn’t help but be impressed. As Koch finished his demonstration and the observers began leaving the room, Pasteur stepped over to him. “C’est un grand progrès, Monsieur,” he said.
In the weeks following the congress, Koch and his assistants would improve the plating technique considerably. After one assistant, Walther Hesse, told his wife
about the gelatin technique and mentioned that it wasn’t yet perfect—the gelatin tended to turn runny in hot weather—she suggested they try agar, a similar but stabler substance derived from seaweed that she used to make jelly. It worked splendidly—so much so that it continues to be the standard medium for most cultures today. The invention was soon improved upon by another assistant in Koch’s lab, Julius Richard Petri, who replaced the flat glass plates that Koch had been using with round plates with raised edges. This, of course, was the petri dish, the very plate that continues to be used to this day in laboratories the world over.
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THE PROCESS OF EXPLORING, PROVING, AND REPLICATING SCIENTIFIC discoveries is, in the twenty-first century, a highly regimented one. Science journals have clear standards of evidence, require several rounds of peer review before publication, and demand that enough data be provided so that other scientists might replicate the experiment, in the hope of replicating the result. In turn, the journals themselves are assessed for their significance and impact—what’s known as impact factor, a measure of how much authority a scientific journal holds in its field. The more frequently a journal’s publications are cited, the higher that journal’s impact factor. This network of citations and ideas and publications is the informing framework for contemporary science. It allows scientists to get their work published and to obtain funding for further research.
Though the process has its faults (belabored and inattentive peer review, exorbitantly expensive journals whose articles are inaccessible to the general public, delays of two or three years between an experiment’s conclusion and its publication), without it, modern science could not happen. It is a remarkably effective system for turning questions into conclusions, and an efficient way to measure the value of science and to reward scientists (through recognition and stature and funding) to do more of it.
But in 1881, this system did not yet exist. An increasing number of scientific journals were being published, many of them, such as The Lancet and Nature in England and Comptes rendus in France, related to the biological and medical sciences. Even then, citations were a recognized part of the process, both putting one’s own work in context and attributing credit to others. But other parts of today’s system—external peer review, for instance—had yet to be established. On the pro side, this allowed science to go from laboratory to publication with remarkable speed; only the editor served as a gatekeeper. Koch’s wound infections paper, for instance, was published just three weeks after he finished it. On the con side, the landscape of publications looked something of a mess, with few checks on research methods and protocols besides the opinion of that one journal editor.
An essential part of this system, then as now, is competition. The base human instinct to beat the other guy is an essential characteristic of science, notwithstanding its tweedy reputation. Without competition, there would be no need for a citation—the coin of the realm for scientists. Without competition, there would be no triumph of discovery, no glory in being first to discern a truth where there had been only questions. Economists have long recognized the essential role of competition in fostering innovation and as a spur toward technological innovation. Competition pushes innovators and companies to develop better products in order both to grow and to dominate markets. Competition makes things happen.
Which brings us back to Koch and Pasteur. While there were undoubtedly any number of practical reasons for Pasteur to turn to anthrax in 1878, including that local outbreak of the disease in rural France, the idea of besting a German scientist likely spurred him on. And now that Pasteur had made such a breakthrough, Koch was clearly game to fight back. Though the progress toward a vaccine went far beyond what he’d been able to achieve, it’s clear that Koch saw Pasteur’s anthrax work as a challenge to his own research on the disease. And he seemed more inclined to defend his turf in return than to give Pasteur his due.
To put it bluntly: Koch came out swinging. A few months after the London meeting, working with his two assistants Georg Gaffky and Friedrich Loeffler, he published a scathing attack on Pasteur’s experimental methods and his conclusions. The world may have hailed Pouilly-le-Fort as a breakthrough for humankind, but Koch wasn’t having it. “Of these conclusions of Pasteur on the etiology of anthrax, there is little which is new, and that which is new is erroneous,” Koch wrote. “Up to now, Pasteur’s work on anthrax has led to nothing.”
Koch challenged the work on every front. He assailed Pasteur’s earthworm hypothesis, casting doubt on whether earthworms could really be a vector for the disease in soil.
The theory on the role of the earthworm in the etiology of anthrax, even as with earlier investigations of Pasteur turned out to be in error; and all the proofs from his anthrax studies allow one to summarize that up to now thanks to Pasteur our knowledge of anthrax has not been enlarged; thus in part his work in this field only confuses what is already fixed or is fast being clarified.
Koch based his criticisms partly on the critical test of reproducibility—Koch had tried and failed to grow the anthrax bacteria at the temperature Pasteur claimed to have done so—but his tone was hyperbolic, crass, and altogether unbecoming. He lashed out at Pasteur with almost casual cruelty. It was quite unlike the self-deprecating fastidiousness of the letter he’d written to Ferdinand Cohn just six years earlier. Was he offended that Pasteur had outdone him? Peeved that his own dominion over anthrax was so short-lived? Whatever the perceived injustice that drove him, Koch threw the growing heft of his reputation at Pasteur’s work. If Koch wanted to measure how much clout he had built up in science, he chose an especially nasty way to evaluate it.
Koch’s attack was reprinted in French in February 1882, and the French scientific world was taken aback. Pasteur quickly sent his assistant Louis Thuillier to Berlin, for the stated purpose of demonstrating the vaccine, but also to allow Pasteur to gather some intelligence on his German rival. Thuillier’s report, full of French condescension, didn’t reflect well on any of them:
M. Koch is not liked by his colleagues. M. Struck [the German official who had given Koch his appointment] is an intriguing ignoramus who has obtained his position as director of the Reichsgesundheitsamt only because he is von Bismarck’s physician. He is very unpopular and his protege, M. Koch, shares some of the contempt in which his protector is held. Furthermore, having always lived in a small town of Posen, far away from the scientific centers, [Koch] is a bit of a rustic, and is ignorant of parliamentary language.
After an initial too-potent dose of vaccine proved toxic to German cows, Thuillier’s experiments were a success. Nonetheless, Koch remained personally unconvinced and publicly unapologetic.
Pasteur himself kept silent until the next September, when he appeared at the International Congress of Hygiene and Demography in Geneva, Switzerland. With Koch sitting in the front row, Pasteur went through the history of his anthrax vaccine, back to the experiments with chicken cholera four years prior. He explained the results of his repeated experiments in Pouilly-le-Fort and subsequent sites. “Yet however blazingly clear the demonstrated truth,” Pasteur remarked, “it has not always had the privilege of being easily accepted. I have encountered, both in France and abroad, obstinate objectors.” In case that wasn’t overt enough, Pasteur implicated Koch outright, referring to the latter’s published critiques. “Dr. Koch . . . finds noth-ing remarkable in this experiment. . . . The author does not believe that I operated as I said I did.” The clear impression was that with all the evidence Pasteur had assembled, Koch was simply in denial.
This was as close as science could get to an outright duel. Pasteur had taken his shot and, by all accounts, scored a hit, with Koch right there in the first row. Moments later, Koch was invited to the lectern for a response. He didn’t hesitate to swat back.
When I saw in the program of the Congress that M. Pasteur was to speak today on the attenuation of virus, I attended the meeting eagerly, hoping to learn somethi
ng new about this very interesting subject. I must confess that I have been disappointed, as there is nothing new in the speech which M. Pasteur has just made. I do not believe it would be useful to respond here to the attacks which M. Pasteur has made on me, for two reasons: first, because the points of disagreement between Pasteur and myself relate only indirectly to the subject of hygiene, and second because I do not speak French well and M. Pasteur does not speak German at all, so that we are unable to engage in a fruitful discussion. I will reserve my response for the pages of the medical journals.
Pasteur quickly retorted that had Koch been able to follow his lecture, he would have easily grasped the new evidence presented. But, he added, he would happily wait for Koch to compose his response in print. Privately, meanwhile, Pasteur wrote with glee to a colleague that “Koch acted ridiculous and made a fool of himself.” He wrote to his son, the former soldier, “It was a triumph for France; that is all I wanted.”
Koch’s reply, published a few weeks later, was an outrageous outburst: ten thousand words of insults, abuse, and condescension. It’s worth quoting one long passage, if only to get an earful of Koch’s venom:
Concerning inoculation against anthrax, all that we heard was some completely useless data about how many thousands of animals had been inoculated. . . . All this material served solely as a vehicle for a violent polemic directed against me. . . . Thus, because of the lack of microscopic investigation, because of the use of impure substances, and because he used unsuitable test animals, Pasteur’s method must be rejected as defective. . . .
His biases got the better of him, and he reported wonderful things about the diseases found in his test animals and about the remains in their corpses. After all, Pasteur is not a physician, and one cannot expect him to make sound judgments about pathological processes and the symptoms of diseases. By so much the more, therefore, were his medical associates obliged to warn him against the grossest errors. . . .