The Great Influenza

by John M. Barry

  The finding only spurred Avery and his colleagues on. More than ever he concentrated on the capsule, forsaking practically everything else. He believed it to be the key to the specific reaction of the immune system, the key to making an effective therapy or vaccine, the key to killing the killer. And he believed that much of what he discovered about the pneumococcus would be applicable to all bacteria.

  Then, in 1928, Fred Griffith in Britain published a striking and puzzling finding. Earlier Griffith had discovered that all known types of pneumococci could exist with or without capsules. Virulent pneumococci had capsules; pneumococci without capsules could be easily destroyed by the immune system. Now he found something much stranger. He killed virulent pneumococci, ones surrounded by capsules, and injected them into mice. Since the bacteria were dead, all the mice survived. He also injected living pneumococci that had no capsules, that were not virulent. Again the mice lived. Their immune systems devoured the unencapsulated pneumococci. But then he injected dead pneumococci surrounded by capsules and living pneumococci without capsules.

  The mice died. Somehow the living pneumococci had acquired capsules. Somehow they had changed. And, when isolated from the mice, they continued to grow with the capsule - as if they had inherited it.

  Griffith's report seemed to make meaningless years of Avery's work - and life. The immune system was based on specificity. Avery believed that the capsule was key to that specificity. But if the pneumococcus could change, that seemed to undermine everything Avery believed and thought he had proved. For months he dismissed Griffith's work as unsound. But Avery's despair seemed overwhelming. He left the laboratory for six months, suffering from Graves' disease, a disease likely related to stress. By the time he returned, Michael Dawson, a junior colleague he had asked to check Griffith's results, had confirmed them. Avery had to accept them.

  *

  His work now turned in a different direction. He had to understand how one kind of pneumococcus was transformed into another. He was now almost sixty years old. Thomas Huxley said, 'A man of science past sixty does more harm than good.' But now, more than ever, Avery focused on his task.

  In 1931, Dawson, then at Columbia University but still working closely with Avery, and an assistant succeeded in changing (in a test tube) a pneumococcus that lacked a capsule into one that had a capsule. The next year people in Avery's own laboratory managed to use a cell-free extract from dead encapsulated pneumococci to do the same thing, to make bacteria without capsules change into ones with capsules.

  One after another the young scientists in his laboratory moved on. Avery kept on. By the late 1930s he was working with Colin MacLeod and Maclyn McCarty, and they now turned all their energies to understanding how this happened. If Avery had demanded precision before, now he demanded virtual perfection, irrefutability. They grew huge amounts of virulent Type III pneumococci, and spent not just hours or days but months and years breaking the bacteria down, looking at each constituent part, trying to understand. The work was of the utmost tedium, and it was work that yielded failure after failure after failure after failure.

  Avery's name was appearing on fewer and fewer papers. Much of that was because he put his name on papers of people in his laboratory only if he had physically performed an experiment included in the research the paper detailed, no matter how much he had contributed conceptually to the work, or how often he had talked over ideas with the investigator. This was highly generous of Avery; usually a laboratory chief puts his or her name on virtually every paper anyone in his laboratory writes. Dubos recalled that he worked under Avery for fourteen years, that Avery influenced nearly all his work but only four times did Avery's name appear on his papers. Another young investigator said, 'I had always felt so deeply that I was an associate of Avery that' with great astonishment I realized for the first time that we had never published a joint paper.')

  But Avery was also publishing less because he had little to report. The work was extraordinarily difficult, pushing the limits of the technically possible. Disappointment is my daily bread, he had said. I thrive on it. But he did not thrive. Often he thought of abandoning the work, abandoning all of it. Yet every day he continued to fill nearly every waking hour with thinking about it. Between 1934 and 1941 he published nothing. Nothing. For a scientist to go through such a dry period is more than depressing. It is a refutation of one's abilities, of one's life. But in the midst of that dry spell, Avery told a young researcher there were two types of investigators: most 'go around picking up surface nuggets, and whenever they can spot a surface nugget of gold they pick it up and add it to their collection' . [The other type] is not really interested in the surface nugget. He is much more interested in digging a deep hole in one place, hoping to hit a vein. And of course if he strikes a vein of gold he makes a tremendous advance.'

  By 1940 he had gone deep enough to believe he would find something, something of value. Between 1941 and 1944, he again published nothing. But now it was different. Now what he was working on excited him as nothing else had. He was gaining confidence that he would reach his destination. Heidelberger recalled, 'Avery would come and talk about his work on the transforming substance' . There was something that told him that this transforming substance was something really fundamental to biology,' to the understanding of life itself.'

  Avery loved an Arab saying: 'The dogs bark, the caravan moves on.' He had nothing to publish because his work was being done chiefly by subtraction. But it was moving on. He had isolated whatever transformed the pneumococcus. Now he was analyzing that substance by eliminating one possibility after another.

  First, he eliminated proteins. Enzymes that deactivated proteins had no effect on the substance. Then he eliminated lipids (fatty acids). Other enzymes that destroyed lipids had no effect on the ability of this substance to transform pneumococci. He eliminated carbohydrates. What he had left was rich in nucleic acids, but an enzyme isolated by Dubos that destroys ribonucleic acid had no effect on the transforming substance either. Each of these steps had taken months, or years. But he could see it now.

  In 1943 he nominally retired and became an emeritus member of the institute. His retirement changed nothing. He worked exactly as he always had, experimenting, pushing, tightening. That year he wrote his younger brother, a physician, about extraordinary findings and in April informed the institute's Board of Scientific Directors. His findings would revolutionize all biology, and his evidence seemed beyond solid. Other scientists who had found what he had found would have published already. Still he would not publish. One of his junior colleagues asked, 'Fess, what more do you want?'

  But he had been burned so long ago in that very first work at Rockefeller, when he had published a sweeping theory encompassing bacterial metabolism, virulence, and immunity. He had been wrong, and he never forgot the humiliation. He did more work. Then, finally, in November 1943 he, MacLeod, and McCarty submitted a paper titled 'Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types. Induction of Transformation by a Desoxyribonucleic Acid Fraction Isolated from Pneumoccus Type III' to the Journal of Experimental Medicine, the journal founded by Welch. In February 1944 the journal published the paper.

  DNA, deoxyribonucleic acid, had been isolated in the late 1860s by a Swiss investigator. No one knew its function. Geneticists ignored it. The molecule seemed far too simple to have anything to do with genes or heredity. Geneticists believed that proteins, which are far more complex molecules, carried the genetic code. Avery, MacLeod, and McCarty wrote, 'The inducing substance has been likened to a gene, and the capsular antigen which is produced in response to it has been regarded as a gene product.'

  Avery had found that the substance that transformed a pneumococcus from one without a capsule to one with a capsule was DNA. Once the pneumococcus changed, its progeny inherited the change. He had demonstrated that DNA carried genetic information, that genes lay within DNA.

  His experiments were exquisite, elegant, and
irrefutable. A Rockefeller colleague conducted confirming experiments on Pfeiffer's B. influenzae.

  Among historians of science, there has been some controversy over how much immediate impact Avery's paper had, largely because one geneticist, Gunther Stent, wrote that it 'had little influence on thought about the mechanisms of heredity for the next eight years.' And Avery's conclusions were not immediately accepted as true by the broad scientific community.

  But they were accepted as true by the scientists who mattered.

  *

  Prior to Avery's discovery (and proof) that DNA carried the genetic code, he was being seriously considered for the Nobel Prize for his lifetime of contributions to knowledge of immunochemistry. But then came his revolutionary paper. Instead of guaranteeing him the prize, the Nobel Committee found it too revolutionary, too startling. A prize would endorse his findings and the committee would take no such risk, not until others confirmed them. The official history of the organization that gives the prize states, 'Those results were obviously of fundamental importance, but the Nobel Committee found it desirable to wait until more became known' .'

  Others were determined to make more known.

  James Watson, with Francis Crick the codiscoverer of the structure of DNA, wrote in his classic The Double Helix that 'there was general acceptance that genes were special types of protein molecules' until 'Avery showed that hereditary traits could be transmitted from one bacterial cell to another by purified DNA molecules' . A very's experiments strongly suggested that future experiments would show that all genes were composed of DNA' . A very's experiment made [DNA] smell like the essential genetic material' . Of course there were scientists who thought the evidence favoring DNA was inconclusive and preferred to believe that genes were protein molecules. Francis, however, did not worry about these skeptics. Many were cantankerous fools who always backed the wrong horses,' not only narrow-minded and dull, but also just stupid.'

  Watson and Crick were not the only investigators seeking the great prize, the greatest prize, the key to heredity and possibly to life, who immediately grasped the significance of Avery's work. Erwin Chargaff, a chemist whose findings were crucial to Watson and Crick's understanding enough about the DNA molecule to determine its structure, said, 'Avery gave us the the first text of a new language, or rather he showed us where to look for it. I resolved to search for this text.'

  Max Delbruck, who was trying to use viruses to understand heredity, said, 'He was very attentive to what we were doing and we were very attentive to what he was doing' . [I]t was obvious that he had something interesting there.'

  Salvador Luria, who worked with Delbruck (Watson was a graduate student under him) similarly rejected Stent's contention that Avery's findings were ignored. Luria recalled having lunch with Avery at the Rockefeller Institute and discussing the implications of his work with him: 'I think it is complete nonsense to say that we were not aware.'

  Peter Medawar observed, 'The dark ages of DNA came to an end in 1944 with' Avery. Medawar called the work 'the most interesting and portentous biological experiment of the 20th century.'

  Macfarlane Burnet was, like Avery, studying infectious diseases, not genes, but in 1943 he visited Avery's laboratory and left astounded. Avery, he said, was doing 'nothing less than the isolation of a pure gene in the form of desoxyribonucleic acid.'

  In fact, what Avery accomplished was a classic of basic science. He started his search looking for a cure for pneumonia and ended up, as Burnet observed, 'opening' the field of molecular biology.'

  Watson, Crick, Delbruck, Luria, Medawar, and Burnet all won the Nobel Prize.

  Avery never did.

  Rockefeller University (the former Rockefeller Institute for Medical Research) did name a gate after him, the only such honor accorded to anyone. And the National Library of Medicine has produced a series of online profiles of prominent scientists; it made Avery the first to be so honored.

  Oswald Avery was sixty-seven years old when he published his paper on 'the transforming principle.' He died eleven years later in 1955, two years after Watson and Crick unfolded DNA's structure. He died in Nashville where he had gone to live to be near his brother, his family. Dubos compared his death to that of Welch, in 1934, and quoted Simon Flexner on Welch's exit from the stage: 'While his body suffered, his mind struggled to maintain before the world the same placid exterior that had been his banner and his shield. Popsy, the physician who had been so greatly beloved, died as he had lived, keeping his own counsel and essentially alone.'

  CHAPTER THIRTY-SIX

  IN THE FIRST YEARS after the pandemic, Paul Lewis continued to head the Henry Phipps Institute at the University of Pennsylvania.

  Yet Lewis was not a happy man. He was one of those who continued to believe that B. influenzae caused the disease and continued to work on it after the epidemic passed. There was irony in that, since he had initially been reluctant to embrace its etiological role, suspecting instead a filterable virus. Perhaps the chief reason for his stubbornness was his own experience. He had not only found the bacillus with consistency, but he had produced a vaccine that seemed to work. True, the navy had administered a vaccine prepared according to his methods to several thousand men and it had proven ineffective, but he had not made that vaccine himself. A smaller batch that he had personally prepared and tested (during the peak of the epidemic, not in its later stages when many vaccines seemed to be working only because the disease itself was weakening) had given solid evidence of effectiveness. Only three of sixty people who received the vaccine developed pneumonia, and none died; a control group had ten pneumonias and three deaths.

  Those results deceived him. In the past he had not always made the right scientific judgment (no investigator does) but this may have been his first significant scientific error. And it seemed to mark the beginning of a downhill slope for him.

  That was not obvious at first. He had already built an international reputation. The German scientific journal Zeitschrift fur Tuberkulose translated and reprinted his work. In 1917 he was invited to give the annual Harvey Lecture on tuberculosis, a great honor; Rufus Cole, for example, would not receive that invitation for another decade. Eighty-five years later, Dr. David Lewis Aronson, a scientist (whose father, a prize-winning scientist, had worked in the best European laboratories and considered Lewis the smartest man he ever met and gave his son Lewis's name) recalled reading that speech: 'You could see Lewis's mind working, the depth of it, and vision, going well beyond what was going on at the time.'

  Lewis's views had broadened indeed. His interests now included mathematics and biophysics, and, with no resources of his own, he asked Flexner to 'arrange for the support' of a physicist Lewis wanted to lure into medicine to examine fluorescent dyes and 'the disinfectant power of light and the penetrating power of light for animal tissues.' Flexner did so, and Flexner continued to be impressed by Lewis's own work, replying by return mail when Lewis sent him a paper, saying that he would publish it in the Journal of Experimental Medicine, calling it 'interesting and important.'

  Yet Lewis's life after the war began pulling him away from the laboratory, frustrating him. Henry Phipps, the U.S. Steel magnate who had given his name to the institute Lewis headed, had not endowed it generously. Lewis's own salary had risen well enough, from $3,500 a year when he started in 1910 to $5,000 just before the war. Flexner still considered him vastly underpaid and saw to it that, immediately after the war, the University of California at Berkeley offered him a professorship. Lewis declined, but Penn raised his salary to $6,000, a substantial income at that time.

  But if his own salary was more than adequate, he needed to fund an entire institute, even if a small one. He needed money for centrifuges, glassware, heating, not to mention 'dieners' (the word still in use for technicians) and young scientists. He needed to raise the money for all that himself. As a result Lewis more and more found himself drawn into the social milieu of Philadelphia, raising money, being charming. More and more he
was becoming a salesman, selling both the institute and himself. He hated it. He hated the time it took from the laboratory, the drain of his energies, the parties. And the country was in the midst of a deep recession, with four million soldiers suddenly thrown back onto the job market, with the government no longer building ships and tanks, with Europe desolate and unable to buy anything. Raising money was more than just difficult.

  In 1921 the University of Iowa approached him. They wanted to become a first-class research institution, and they wanted him to run the program, to build the institution. The state would supply the money. Flexner was more than just a mentor to Lewis, and Lewis confided in him that the Iowa job seemed 'heavy, safe and of limited inspiration. You know very well that I do not thrive on routine.' And at Phipps, 'Some of the work underway has great potential I believe' . You will see that I am trying to convince myself that I have a right to gamble here as against a rather dull safe outlook at Iowa City. A word from you would be much appreciated.'

  Flexner advised him to accept the offer: 'All I have heard of the medical situation at Iowa City is favorable,' a pretty sharp contrast to the [situation] in Philadelphia. It is definite and has the elements of permanency' . I have no doubt under the influence of your vigorous guidance, the department (although quite large) over which you would preside would become so notable that the State would stand back of you in any enlargement.'

  He did not tell Lewis how well he thought the job might suit him, how extraordinary his gifts for a job like that were. But Flexner did tell a senior colleague that Lewis 'might really come to exercise a real influence in medical teaching and research.' There was perhaps some of what Welch had in him, that Lewis had 'quite unusual gifts of exposition.' He had broad knowledge, perhaps he even leaked knowledge, and, whether he realized it or not, he could inspire. Indeed, Flexner believed he could 'be master of the field.'