The Great Influenza: The Epic Story of the Deadliest Plague in History - John M. Barry (2004)
Part VII. THE RACE
LABORATORIES EVERYWHERE had turned to influenza. Pasteur’s protégé Émile Roux, one of those who had raced German competitors for a diphtheria antitoxin, directed the work at the Pasteur Institute. In Britain virtually everyone in Almroth Wright’s laboratory worked on it, including Alexander Fleming, whose later discovery of penicillin he first applied to research on Pfeiffer’s so-called influenza bacillus. In Germany, in Italy, even in revolution-torn Russia, desperate investigators searched for an answer.
But by the fall of 1918 these laboratories could function only on a far-reduced scale. Research had been cut back and focused on war, on poison gas or defending against it, on preventing infection of wounds, on ways to prevent diseases that incapacitated troops such as “trench fever,” an infection related to typhus that was not serious in itself but had taken more troops out of the line any other disease. Laboratory animals had become unavailable; armies consumed them for testing poison gas and similar purposes. The war had also sucked into itself technicians and young researchers.
Laboratories in both Europe and the United States were affected, but Europeans suffered far more, with their work limited by shortages not only of people but of everything from coal for heat to money for petri dishes. At least those resources Americans had. And if the United States still lagged behind Europe in the number of investigators, it no longer lagged in the quality of investigators. The Rockefeller Institute had already become arguably the best research institute in the world; out of a mere handful of scientists working there then, one man had already won the Nobel Prize and two would win it. In the most relevant area of work, in pneumonia, the Rockefeller Institute had a clear lead over the rest of the world. And Rockefeller scientists were hardly the only Americans doing world-class work.
For Welch, Michigan’s Victor Vaughan, Harvard’s Charles Eliot, Penn’s William Pepper, and the handful of colleagues who had pushed so hard for change had succeeded. They had transformed American medical science. If that transformation had only just occurred, if it had only recently risen to the level of Europe, it also had the vitality that comes from recent conversion. And the nation at large was not so exhausted as Europe. It was not exhausted at all.
As influenza stretched its fingers across the country and began to crush out lives in its grip, virtually every serious medical scientist—and many simple physicians who considered themselves of scientific bent—began looking for a cure. They were determined to prove that science could indeed perform miracles.
Most of them, simply, were not good enough to address the problem with any hope of success. They tried anyway. Their attempt was heroic. It required not just scientific ability but physical courage. They moved among the dead and dying, reached swabs into mouths and nasal passages of the desperately ill, steeped themselves in blood in the autopsy room, dug deep into bodies, and struggled to grow from swabbings, blood, and tissue the pathogen that was killing more humans than any other in history.
A few of these investigators, possibly as few as a few dozen, were smart enough, creative enough, knowledgeable enough, skilled enough, and commanded enough resources that they were not on a fool’s errand. They could confront this disease with at least the hope of success.
In Boston, Rosenau and Keegan continued to study the disease in the laboratory. The bulk of the army’s pneumonia commission had been ordered to Camp Pike, Arkansas, where, even as Welch arrived at Devens, they began investigating “a new bronchopneumonia.” The Rockefeller team whom Welch had brought to Devens headed back to New York, where they added Martha Wollstein, a respected bacteriologist also associated with the Rockefeller Institute, to the effort; she had studied the influenza bacillus since 1905. In Chicago at the Memorial Institute for Infectious Diseases, Ludwig Hektoen dove into the work. And at the Mayo Clinic, E. C. Rosenow did the same. The only civilian government research institution, the Public Health Service’s Hygienic Laboratory and its director George McCoy joined in.
But of all those working on it in the United States, perhaps the most important were Oswald Avery at Rockefeller, William Park and Anna Williams at the New York City Department of Public Health, and Paul Lewis in Philadelphia.
Each of them brought a different style to the problem, a different method of doing science. For Park and Williams, the work would come as close to routine as something could be in the midst of such extreme crisis; their efforts would have no impact on their own lives in any personal sense, although they would help direct research on influenza down the path that ultimately yielded the right answer. For Avery the work would confirm him in a direction that he would follow for decades, decades first of enormous frustration but then of momentous discovery—in fact a discovery that opened the door to an entire universe even now just beginning to be explored. For Lewis, although he could not have known it, his work on influenza would mark a turning point in his own life, one that would lead to a great tragedy, for science, for his family, and for himself.
It was not a good time to confront a major new threat in the Bureau of Laboratories of the New York City Department of Public Health, the bureau Park ran and in which Williams worked. For they had a special problem: New York City politics.
On January 1, 1918, Tammany Hall reclaimed control of the city. Patronage came first. Hermann Biggs, the pioneer who had built the department, had left a year earlier to become state health commissoner; Biggs had been untouchable because he had treated a top Tammany leader who had protected the entire department during prior Tammany administrations. His successor was not untouchable. Mayor John Hylan replaced him two weeks after taking control. But most jobs in the Department of Health were not patronage positions, so to create vacancies Tammany began to smear the best municipal health department in the world. Soon Hylan demanded the firing of division chiefs and the removal of highly respected physicians on the advisory board.
Even the new Tammany-appointed health commissioner balked at that and resigned, leaving the department leaderless. The mayor was standing on the sidewalk outside City Hall when a crony introduced Royal Copeland to him, said he was a loyal Tammany man, and suggested the mayor name him the new health commissioner. But Copeland, dean of a homeopathic medical school, was not even an M.D.
Nonetheless the mayor agreed to appoint him. The three men then climbed the steps to his office, and Copeland was sworn in.
The best municipal public health department in the world was now run by a man with no belief in modern scientific medicine and whose ambitions were not in public health but in politics. If Tammany wanted vacancies to fill with loyalists, that is what he would give them. (Copeland once explained his loyalty to Tammany in simple terms: “Man is a social animal and cannot work without cooperation. Organization is a necessity and my organization is Tammany.” A few years later Tammany would repay his loyalty by carrying him to the United States Senate.) So he continued the machine’s efforts to disassemble the department. One of the best division heads was first threatened with criminal charges and when that failed he was hauled to a civil-service hearing on charges of “neglect of duty, inefficiency, and incompetency.”
Park had run the department’s laboratory division since 1893, had never involved himself in politics, and was himself untouchable. He continued to do excellent science in the midst of this turmoil; soon after Avery and Cole and others at Rockefeller developed their serum against Types I and II pneumococcus, Park developed a procedure for “typing” the pneumococcus so simple that any decent laboratory could perform it within thirty minutes, allowing nearly immediate use of the right serum for treatment.
But now he had to defend the department. He helped organize a defense, and the defense became national. Criticism rained down on Tammany from the city, the state, from Baltimore, Boston, Washington. Welch and nearly every major figure in medicine attacked Tammany. Rupert Blue, the head of the U.S. Public Health Service, publicly called upon the mayor to desist.
Tammany backed off, and Copeland embarked on a public relations campaign to repair the damage to himself and his “organization,” relying on patriotism to stifle criticism. By late summer the frenzy had died down, but what had been the best public health department in the world was demoralized. The internationally respected director of the Bureau of Public Health Education resigned. The deputy commissioner of health, in office twenty years, resigned, and the mayor replaced him with his personal physician.
On September 15, New York City’s first influenza death occurred. By then the disease had long since begun leaking out of the army and navy bases into the civilian population of Massachusetts.
In two polio epidemics in the preceding decade, public health officials had all but closed down the city. But now Copeland did nothing. Three days later, as hospitals began filling with influenza cases, he made influenza and pneumonia reportable diseases, while simultaneously stating that “other bronchial diseases and not the so-called Spanish influenza are said to be responsible for the illness of the majority of persons who were reported to be ill with influenza….”
A few days more and even Copeland could no longer deny reality. People could see disease all about them. Finally he imposed a quarantine on victims and warned, “The health department is prepared to compel patients who may be a menace to the community to go to hospitals.” He also assured all concerned “that the disease is not getting away from the control of the health department but is decreasing.”
Park knew better. As a student in Vienna in 1890 he had watched that influenza pandemic kill one of his professors and wrote, “We mourn for him and for ourselves.” And for several months now he and others in his laboratory had followed the progress of the disease. He was well aware of the transformation of the City of Exeter into a floating morgue and of serious cases in July and August on ships arriving in New York harbor. Those cases did one good thing: they relieved the laboratory of political pressure and allowed him and it to concentrate on work.
In late August he and Anna Williams began devoting all their energies to the disease. In mid-September they were called to Camp Upton in Long Island. The disease had just reached there, and few deaths had occurred—yet—but already a single barracks, filled with soldiers from Massachusetts, had two thousand cases.
Park and Williams had collaborated now for a quarter of a century, and they complemented each other perfectly. He was a quiet brown-eyed man with a somewhat reserved, even aristocratic, bearing. He had a claim to the social elite; his father’s ancestors arrived in America in 1630, his mother’s in 1640. He also felt a calling. Three great-aunts had been missionaries and were buried in Ceylon, a cousin to whom he was very close became a minister, and Park himself had considered becoming a medical missionary.
He had a serious purpose and curiosity per se did not drive that purpose. His seeking of knowledge in the laboratory served his purpose only to the extent, as he saw it, that it served God’s purpose. He donated his salary as professor of bacteriology at New York University to the laboratory, or at least into the hands of some of his professional workers who struggled on city salaries. He also involved himself directly with patients, often working the diphtheria wards at the city-run Willard Parker Hospital across the street from his laboratory. The hospital was a new, gleaming place, thirty-five iron bedsteads to each ward, with water closets and bathtubs of marble with porcelain lining, the polished hardwood floors washed every morning with a 1:1,000 solution of bichloride of mercury, the same solution in which patients themselves bathed at discharge and admission.
Methodical, somewhat stolid, he was a master bureaucrat in the best sense of the word; he had run the health department’s Bureau of Laboratories for decades and had always looked for ways to make the system work. What drove him was the desire to bring laboratory research to patients. He was a pragmatist. Goethe observed that one searches where there is light. Some scientists try to create new light to shine on problems. Park was not one such; his forte was making exhaustive explorations with existing light.
It was his and Williams’s work that had led to mass production of inexpensive diphtheria antitoxin. It was his work that had marked America’s acceptance as a scientific equal of Europe, when that international conference had endorsed his views on tuberculosis over Koch’s. His scientific papers were exact if not quite elegant, and he matched his precision with a deeply probing and careful mind.
It was that precision, and the missionary’s sense of right and wrong, that had led to his public feud over meningitis serum a few years earlier with Simon Flexner and the Rockefeller Institute. In 1911 Park had created the Laboratory for Special Therapy and Investigation, at least in part to rival the Rockefeller Institute. He was a few years older now, but no mellower. He and Flexner remained “pretty acid” about each other, noted one scientist who knew them both well, with “no love lost between them,” but despite their animosity both of them cooperated with the other whenever called upon, and neither held back information.
(This openness was a far cry from the atmosphere at some other laboratories, including the Pasteur Institute. Pasteur himself had once advised a protégé not to share information with outsiders, saying, “Keep your cadavers to yourself.” When Anna Williams visited there, she was refused any information on a pneumonia antiserum until it was published, and also had to promise that after she left, she would say nothing about anything else she had seen until it was published. Even in publication Pasteur scientists did not tell everything. As Biggs wrote Park, “Marmorek has taught her how it’s done—it is secret of course. In the usual way, he omitted the essential thing in his article.”)
If Park was almost stolid, Anna Williams injected a certain wildness and creativity into the laboratory. She loved going up in airplanes with stunt fliers—a reckless act in pre–World War I airplanes—and loved sudden fast turns and out-of-control drops. She loved to drive and was always speeding; when traffic was stalled, she often simply pulled into the opposite side of the road and proceeded, and she had a string of traffic tickets to prove it. Once she took a mechanic’s course and decided to take her Buick engine apart—but failed to put it back together. In her diary she wrote, “From my earliest memories, I was one of those who wanted to go places. When I couldn’t go, I would have my dreams about going. And, such wild dreams were seldom conceived by any other child.”
Despite—or more likely because of—her wildness, she had established herself as the premier woman medical scientist in America. Her achievement came at a price.
She was unhappy. She was also lonely. At the age of forty-five, she wrote, “I was told today that it was quite pathetic that I had no one particular friend.” She and Park had worked together for decades but they maintained a careful distance. To her diary she confided, “There are degrees to everything, including friendship…. [T]here is no sentimentality about my friendships and little sentiment.” Religion gave her no relief. She wanted too much from it. She told herself that Jesus knew that his anguish was momentary and that in exchange he was going to save the world. “This knowledge…if we were sure, oh! what would we not be willing to undergo.” Of course she had no such knowledge. She could only recall “all the good things I have been taught…[and] act as if they were true.”
Yet in the end, although jealous of those who lived a normal life, she still preferred “discontent rather than happiness through lack of knowledge.” Instead she did content herself with the fact that “I have had thrills.” Analyzing herself, she confided in her diary that what mattered to her more were “love of knowledge,” “love of appreciation,” “love of winning,” “fear of ridicule,” and “power to do, to think new things.”
These were not Park’s motives, but she and Park made a powerful combination. In science, at least, she had had thrills indeed.
She was fifty-five years old in 1918. Park was the same age. There were no thoughts of thrills on the long drive and rough roads from Manhattan to Camp Upton, even though Park indulged her and let her drive. At the camp the military doctors, knowing what was happening at Devens, begged for advice.
Park and Williams were experts on vaccine therapy. Even during the polio epidemics they had done excellent science, if only to prove the negative; Park had tried to develop but instead proved the ineffectiveness of several treatments. This time they felt hopeful; their work with streptococci and pneumococci, like that of the Rockefeller Institute’s, was promising. But as yet Park and Williams had no advice to give; they could only swab the throats and nasal passages of the sick at Upton, return to their laboratory, and proceed from there.
They also got material from another source, which Williams never forgot. It was her first influenza autopsy; the body was that of, she later wrote, “a fine-looking youth from Texas” who shared her last name. She stood staring at his fine features wondering about him, wondering even if he was some distant relative, and noting, “Death occurring so quickly it left little or no marks of disease anywhere except for the lungs.”
She could not have looked at his perfect form, perfect but for death, and not wondered just what the country was about to endure. The drive back to New York, the car filled with swabbings from mucosal membranes, sputum, and tissue samples of a mysterious and lethal disease, likely alternated between intense conversation and silence, conversation as they planned their experiments and silence knowing the silence of the laboratory that awaited them.
There was in fact nothing like Park’s laboratory in the world. From outside on the street, Park could look up with pride on the six-story building, the floors of laboratories, knowing that his successes had built them. Entirely dedicated to diagnostic testing, production of sera and antitoxins, and medical research, his creation sat at the foot of East Sixteenth Street with the teeming wharfs of the East River just beyond.
Streetcars, horse-drawn carriages, and automobiles clattered past, and the smell of manure still mixed with that of gasoline and oil. There was all the sweat and ambition and failure and grit and money of New York City, all that made the city what it was and is.
Inside the building Park oversaw a virtual industry. More than two hundred workers reported to him, nearly half of them scientists or technicians in one laboratory or another, each one with lab tables laid out in horizontal rows, gas burners in virtually constant use on each table, glassware stacked on shelves above the tables as well as filling shelves along the walls, the rooms often hissing with steam and humidity from the autoclaves used to sterilize.
No other laboratory anywhere, not in any institute, not in any university, not sponsored by any government, not run by any pharmaceutical company, had the combination of scientific competence, epidemiological and public health expertise, and ability to carry out directed research—to focus all resources on one question and not be deflected from that search no matter how enticing or important a finding might be—intent on immediate practical results.
His laboratory could also function in extreme crisis. It had done so before: preventing outbreaks of cholera and typhoid, triumphing over diphtheria, helping in meningitis epidemics. It had done so not only in New York City but all over the country; when requested, Park had sent teams to fight outbreaks of disease elsewhere.
And one other ability made the department unique. If a solution was found, it could produce serum and vaccines in industrial quantities as quickly as—and of better quality than—any drug manufacturer in the world. Indeed, it had been so successful making antitoxins that drug makers and city physicians had combined to use all their political power to limit that production. But now Park could quickly gear back up. Because of the assignment to produce serum for the army, he had just quadrupled the number of horses he could infect and then bleed.
So it was not surprising that soon after Park returned from Camp Upton, he received a telegram from Richard Pearce, head of the National Research Council’s section on medicine. Pearce was grabbing at any information he could get from the French, the British, even the Germans, and distributing it to investigators everywhere. He was also breaking the questions about influenza into pieces and asking each of a handful of investigators to focus on a single piece. From Park he wanted to know “the nature of the agent causing the so-called Spanish influenza…[and] pure cultures of the causative organism if obtainable…. Will your lab undertake the necessary bacteriological studies and make reports as quickly as possible to the undersigned?”
Park instantly wired back, “Will undertake work.”
It was as if the laboratory had gone to war, and Park was confident of victory. As he reviewed every published and unpublished scrap of data on the disease from laboratories around the world, he was unimpressed and dismissed most of it with near contempt. Certain his lab could do better, believing that others’ sloppiness at least partly contributed to their failure to understand the disease, he laid extraordinarily ambitious plans. In addition to finding the pathogen, in addition to finding a vaccine or serum or both, in addition to producing that drug in huge quantities, in addition to communicating to others the precise procedures to follow so they could produce it, he intended still more. He intended to make the most thorough study of any disease outbreak ever, selecting a large sample of people and, as many of them inevitably became ill, monitoring them through the most sophisticated possible laboratory and epidemiological means. The workload would be enormous, but he believed that his department could handle it.
But within days, almost within hours, the disease began to overwhelm the department. Park had already compensated for the loss of labor to the war by analyzing every system and maximizing efficiency (installing, for example, a vacuum pump that in fifteen minutes could fill three thousand tubes with individual vaccine doses), and even changing accounting methods. But now, as influenza struck first one janitor or technician or scientist at a time, then four at a time, then fifteen at a time, the laboratory reeled. Not so long before, when the Health Department had tracked a typhus outbreak to ground, four of his workers had died of typhus—most likely from laboratory infection. Now people in Park’s own lab were again sick, some dying.
Influenza had humbled him, and quickly. He abandoned both his arrogance about the work of others and his own ambitious plans. Now he was trying to get just one thing right, the important thing. What was the pathogen?
Meanwhile, the world seemed to shift underfoot. To Park and Williams and to others in other laboratories racing to find an answer, it must have seemed as if they could see this great catastrophe approaching but had to remain frozen in place, all but incapable of doing anything to defeat or avoid it. It was almost as if one’s foot were caught under rocks in a tidal pool while the tide came in—the water rising to the knees, to the waist, one sucking in a deep breath then doubling over to try to pry one’s foot loose and straightening to feel the water at one’s neck, the swell of a wave passing over one’s head….
New York City was panicking, terrified.
By now Copeland was enforcing strict quarantines on all cases. There were literally hundreds of thousands of people sick simultaneously, many of them desperately sick. The death toll ultimately reached thirty-three thousand for New York City alone, and that understated the number considerably since statisticians later arbitrarily stopped counting people as victims of the epidemic even though people were still dying of the disease at epidemic rates—still dying months later at rates higher than anywhere else in the country.
It was impossible to get a doctor, and perhaps more impossible to get a nurse. Reports came in that nurses were being held by force in the homes of patients too frightened and desperate to allow them to leave. Nurses were literally being kidnapped. It did not seem possible to put more pressure on the laboratory. Yet more pressure came.
The pressure pushed Park to abandon more than his ambitious plans. He had always been meticulous, had never compromised, had built much of his scientific reputation on exposing the flawed work of others, always moving forward carefully, basing his own experiments upon well-established premises and with as few assumptions as possible. “On the basis of experimental facts,” he had always said, “we are justified in…”
Now Park had no leisure for justification. If he was to have any impact on the course of the epidemic he would have to guess—and guess right. So those in his laboratory would, he reported, “study closely only the more dominant types that were demonstrated by our procedure…. We recognized that our methods…did not take into account…heretofore undescribed organisms that might have an etiologic relationship to these infections.”
The laboratory had only two constants. One was an endless supply of samples, of swabbings, blood, sputum, and urine from live patients and organs from the dead. “We had plenty of material, I am sorry to say,” Williams observed laconically.
And they had their routine. Only the need to keep to discipline saved the laboratory from utter chaos. There was nothing even faintly exciting about this work; it was pure tedium, and pure boredom. And yet every step involved contact with something that could kill, and every step involved passion. Technicians took sputum samples from patients in the hospital and immediately—they could not wait even an hour, or bacteria from the patient’s mouth could penetrate into the sputum and contaminate it—began working with it. The steps began with “washing”: placing each small lump of balled mucus in a bottle of sterile water, removing it and repeating the process five times, then breaking up the mucus, washing it more, passing a platinum loop—a thin circle of platinum, like something one uses to blow bubbles—through it to transfer it to a test tube, taking another loop and repeating the step half a dozen times. Each step took time, time while people died, but they had no choice. They needed each step, needed to dilute the bacteria to prevent too many colonies from growing in the same medium. Then they took more time, more steps, isolating each of these growths.
Everything mattered. The most tedious tasks mattered. Washing glassware mattered. Contaminated glassware could ruin an experiment, waste time, cost lives. In the course of this work, 220,488 test tubes, bottles, and flasks would be sterilized. Everything mattered, and yet no one knew who would report to work each day, who would not—and who would suddenly be carried across the street to the hospital—and if someone failed to come into work it was nearly impossible to keep track of such simple jobs as removing growing cultures from incubators.
There were dozens of ways to grow bacteria but often only one way to grow a particular kind. Some grow only without oxygen, others only with it in plentiful supply. Some require alkaline media, others acid. Some are extremely delicate, others stable.
Every step, every attempt to grow the pathogen, meant effort, and effort meant time. Every hour incubating a culture meant time. They did not have time.
Four days after accepting the task from Pearce, Park wired, “The only results so far that are of real importance have been obtained in two fatal cases, one a man coming from Brooklyn Navy Yard and one a doctor from the naval hospital in Boston. Both developed an acute septic pneumonia and died within a week of the onset of the first infection. In both cases the lungs showed a beginning pneumonia and in smears very abundant streptococci…. There were absolutely no influenza bacilli in either of the lungs.”
The failure to find the “influenza bacillus” maddened Park. His best hope to produce a vaccine or serum would be to find a known pathogen, and the most likely suspect was the one Pfeiffer had named Bacillus influenzae. Pfeiffer had been and still was confident it caused the disease. Park would not hesitate to rule B. influenzae out if he did not find good evidence for it, but he had the utmost respect for Pfeiffer. Working in these desperate circumstances, he wanted to confirm rather than reject Pfeiffer’s work. He wanted the answer to be Pfeiffer’s bacillus. That would give them a chance, a chance to produce something that saved thousands of lives.
B. influenzae was a particularly difficult bacteria to isolate. It is tiny, even by the standards of bacteria, and usually occurs singly or in pairs rather than in large groups. It requires particular factors, including blood, in culture medium for it to grow. It grows only within a very narrow range of temperatures, and its colonies are minute, transparent, and without structure. (Most bacteria form distinctive colonies with a particular shape and color, distinctive enough that they can sometimes be identified just by looking at the colony in the same way that some ants can be identified by the form of their anthill.) B. influenzae grows only on the surface of the medium, since it depends heavily upon oxygen. It is also difficult to stain, hence difficult to see under the microscope. It is an easy target to miss unless one is specifically looking for it and unless one uses excellent technique.
While others in the lab searched for other organisms, Park asked Anna Williams to concentrate on finding Pfeiffer’s. Anna Williams found it. She found it constantly. Ultimately, once she perfected her technique, she would find it in 80 percent of all samples from the Willard Parker Hospital, in every single sample from the Marine Hospital, in 98 percent of the samples from the Home for Children.
As much as he wanted Williams to be right, he would not let his desire corrupt his science. He went a step further, to “the most delicate test of identity…agglutination.”
“Agglutination” refers to a phenomenon in which antibodies in a test tube bind to the antigen of the bacterium and form clumps, often large enough to be visible to the naked eye.
Since the binding of antibodies to an antigen is specific, since the antibodies to the influenza bacillus will bind to only that bacteria and to no other, it is a precise confirmation of identity. The agglutination tests proved without doubt that Williams had found Pfeiffer’s influenza bacillus.
Less than a week after first reporting his failure to find it, Park wired Pearce that B. influenzae “would seem to be the starting point of the disease.” But he was well aware that his methods had been less than thorough, adding, “There is of course the possibility that some unknown filterable virus may be the starting point.”
The report had consequences. Park’s laboratory began the struggle to produce an antiserum and vaccine to Pfeiffer’s bacillus. Soon they were culturing liters and liters of the bacteria, transporting it north, and injecting it into the horses on the Health Department’s 175-acre farm sixty-five miles north of the city.
But the only way to know for certain that B. influenzae caused the disease was to follow Koch’s postulates: isolate the pathogen, use it to recreate the disease in an experimental animal, and then re-isolate the pathogen from the animal. The bacillus did kill laboratory rats. But their symptoms did not resemble influenza.
The results, suggestive as they were, did not fully satisfy Koch’s postulates. In this case the necessary experimental animal was man.
Human experiments had begun. In Boston, Rosenau and Keegan were already trying to give the disease to volunteers from a navy brig.
None of the volunteer subjects had yet gotten sick. One of the doctors conducting the study did. In fact he died of influenza. In a scientific sense, however, his death demonstrated nothing.