by Bill Bryson
It is sometimes called the Great Swine Flu epidemic and sometimes the Great Spanish Flu epidemic, but in either case it was ferocious. The First World War killed 21 million people in four years; swine flu did the same in its first four months. Almost 80 per cent of American casualties in the First World War came not from enemy fire, but from flu. In some units the mortality rate was as high as 80 per cent.
Swine flu arose as a normal, non-lethal flu in the spring of 1918, but somehow, over the following months—no-one knows how or where—it mutated into something more severe. A fifth of victims suffered only mild symptoms, but the rest became gravely ill and many died. Some succumbed within hours; others held on for a few days.
A woman demonstrates a flu mask, a device of obvious inconvenience and doubtful efficacy, in the closing days of the flu epidemic. An abiding mystery of the epidemic is how it erupted suddenly, all over the world, in places widely separated by oceans. (credit 20.14)
In the United States, the first deaths were recorded among sailors in Boston in late August 1918, but the epidemic quickly spread to all parts of the country. Schools closed, public entertainments were shut down, people everywhere wore masks. It did little good. Between autumn 1918 and spring the following year, 548, 452 people died of the flu in America. The toll in Britain was 220,000, with similar numbers in France and Germany. No-one knows the global toll, as records in the third world were often poor, but it was not less than twenty million and probably more like fifty million. Some estimates have put the global total as high as a hundred million.
In an attempt to devise a vaccine, medical authorities conducted experiments on volunteers at a military prison on Deer Island in Boston Harbor. The prisoners were promised pardons if they survived a battery of tests. These tests were rigorous to say the least. First, the subjects were injected with infected lung tissue taken from the dead and then sprayed in the eyes, nose and mouth with infectious aerosols. If they still failed to succumb, they had their throats swabbed with discharges taken straight from the sick and dying. If all else failed, they were required to sit open-mouthed while a gravely ill victim was sat up slightly and made to cough into their faces.
Out of—somewhat amazingly—three hundred men who volunteered, the doctors chose sixty-two for the tests. None contracted the flu—not one. The only person who did grow ill was the ward doctor, who swiftly died. The probable explanation for this is that the epidemic had passed through the prison a few weeks earlier and the volunteers, all of whom had survived that visitation, had a natural immunity.
Much about the 1918 flu epidemic is understood poorly or not at all. One mystery is how it erupted suddenly, all over, in places separated by oceans, mountain ranges and other earthly impediments. A virus can survive for no more than a few hours outside a host body, so how could it appear in Madrid, Bombay and Philadelphia all in the same week?
The probable answer is that it was incubated and spread by people who had only slight symptoms or none at all. Even in normal outbreaks, about 10 per cent of people in any given population have the flu but are unaware of it because they experience no ill effects. And because they remain in circulation they tend to be the great spreaders of the disease.
That would account for the 1918 outbreak’s widespread distribution, but it still doesn’t explain how it managed to lie low for several months before erupting so explosively at more or less the same time all over. Even more mysterious is that it was most devastating to people in the prime of life. Flu normally is hardest on infants and the elderly, but in the 1918 outbreak deaths were overwhelmingly among people in their twenties and thirties. Older people may have benefited from resistance gained from an earlier exposure to the same strain, but why the very young were similarly spared is unknown. The greatest mystery of all is why the 1918 flu was so ferociously deadly when most flus are not. We still have no idea.
From time to time certain strains of virus return. A disagreeable Russian virus known as H1N1 caused severe outbreaks over wide areas in 1933, then again in the 1950s and yet again in the 1970s. Where it went in the meantime each time is uncertain. One suggestion is that viruses hide out unnoticed in populations of wild animals before trying their hand at a new generation of humans. No-one can rule out the possibility that the great swine flu epidemic might once again rear its head.
And if it doesn’t, others well might. New and frightening viruses crop up all the time. Ebola, Lassa and Marburg fevers all have tended to flare up and die down again, but no-one can say that they aren’t quietly mutating away somewhere, or simply awaiting the right opportunity to burst forth in a catastrophic manner. It is now apparent that AIDS has been among us much longer than anyone originally suspected. Researchers at the Manchester Royal Infirmary discovered that a sailor who had died of mysterious, untreatable causes in 1959 in fact had AIDS. Yet, for whatever reasons, the disease remained generally quiescent for another twenty years.
An AIDS awareness advertisement in Bayelsa, Nigeria. AIDS, a completely preventable disease, is now the number-one killer in Africa, claiming 6,000 lives a day. On present trends, one quarter of all people in sub-Saharan Africa will die of the illness. (credit 20.15)
The miracle is that other such diseases haven’t gone rampant. Lassa fever, which wasn’t first detected until 1969, in West Africa, is extremely virulent and little understood. In 1969, a doctor at a Yale University lab in New Haven, Connecticut, who was studying Lassa fever came down with it. He survived, but, more alarmingly, a technician in a nearby lab, with no direct exposure, also contracted the disease and died.
Happily the outbreak stopped there, but we can’t count on always being so fortunate. Our lifestyles invite epidemics. Air travel makes it possible to spread infectious agents across the planet with amazing ease. An Ebola virus could begin the day in, say, Benin, and finish it in New York or Hamburg or Nairobi, or all three. It means also that medical authorities increasingly need to be acquainted with pretty much every malady that exists everywhere, but of course they are not. In 1990, a Nigerian living in Chicago was exposed to Lassa fever on a visit to his homeland, but didn’t develop symptoms until he had returned to the United States. He died in a Chicago hospital without diagnosis and without anyone taking any special precautions in treating him, unaware that he had one of the most lethal and infectious diseases on the planet. Miraculously, no-one else was infected. We may not be so lucky next time.
A greatly magnified Ebola virus. Though extremely lethal, just 1,600 cases of Ebola fever are known to have occurred since the disease was first reported in central Africa in 1976. Where the virus resides between outbreaks is a mystery. (credit 20.16)
And on that sobering note, it’s time to return to the world of the visibly living.
A formidable-looking Anomalocaris glides past two spiky Hallucigenia in a recreation of the Cambrian seas from 500 million years ago, at just the time when complex life appeared suddenly to burst forth on Earth—the famous “Cambrian explosion.” Because such animals rarely fossilized, almost nothing was known of them until a lucky discovery in the Canadian Rockies in 1909 uncovered one of the world’s great fossil beds, the Burgess Shale. (Credit 21.1)
LIFE GOES ON
It isn’t easy to become a fossil. The fate of nearly all living organisms—over 99.9 per cent of them—is to compost down to nothingness. When your spark is gone, every molecule you own will be nibbled off you or sluiced away to be put to use in some other system. That’s just the way it is. Even if you make it into the small pool of organisms, the less than 0.1 per cent, that don’t get devoured, the chances of being fossilized are very small.
In order to become a fossil, several things must happen. First, you must die in the right place. Only about 15 per cent of rocks can preserve fossils, so it’s no good keeling over on a future site of granite. In practical terms the deceased must become buried in sediment where it can leave an impression, like a leaf in wet mud, or decompose without exposure to oxygen, permitting the molecules in its bones and
hard parts (and very occasionally softer parts) to be replaced by dissolved minerals, creating a petrified copy of the original. Then, as the sediments in which the fossil lies are carelessly pressed and folded and pushed about by Earth’s processes, the fossil must somehow maintain an identifiable shape. Finally, but above all, after tens of millions or perhaps hundreds of millions of years hidden away, it must be found and recognized as something worth keeping.
Only about one bone in a billion, it is thought, ever becomes fossilized. If that is so, it means that the complete fossil legacy of all the Americans alive today—that’s 270 million people with 206 bones each—will only be about fifty bones, one-quarter of a complete skeleton. That’s not to say, of course, that any of these bones will ever actually be found. Bearing in mind that they can be buried anywhere within an area of slightly over 9.3 million square kilometres, little of which will ever be turned over, much less examined, it would be something of a miracle if they were. Fossils are in every sense vanishingly rare. Most of what has lived on Earth has left behind no record at all. It has been estimated that less than one species in ten thousand has made it into the fossil record. That in itself is a stunningly infinitesimal proportion. However, if you accept the common estimate that the Earth has produced thirty billion species of creature in its time, and Richard Leakey and Roger Lewin’s statement (in The Sixth Extinction) that there are 250,000 species of creature in the fossil record, that reduces the proportion to just one in 120,000. Either way, what we possess is the merest sampling of all the life that the Earth has spawned.
Moreover, the record we do have is hopelessly skewed. Most land animals, of course, don’t die in sediments. They drop in the open and are eaten or left to rot or weather down to nothing. The fossil record, consequently, is almost absurdly biased in favour of marine creatures. About 95 per cent of all the fossils we possess are of animals that once lived under water, mostly in shallow seas.
I mention all this to explain why on a grey day in February I went to the Natural History Museum in London to meet a cheerful, vaguely rumpled, very likeable palaeontologist named Richard Fortey.
Fortey knows an awful lot about an awful lot. He is the author of a wry, splendid book called Life: An Unauthorised Biography, which covers the whole pageant of animate creation. But his first love is a type of marine creature called trilobites, which once teemed in Ordovician seas but haven’t existed for a long time except in fossilized form. All trilobites shared a basic body plan of three parts, or lobes—head, tail, thorax—from which comes the name. Fortey found his first when he was a boy clambering over rocks at St David’s Bay in Wales. He was hooked for life.
A well-preserved trilobite, a creature that dominated the oceans for three hundred million years—double the reign of dinosaurs. (Credit 21.2)
He took me to a gallery of tall metal cupboards. Each cupboard was filled with shallow drawers, and each drawer was filled with stony trilobites—twenty thousand specimens in all.
“It seems like a big number,” he agreed, “but you have to remember that millions upon millions of trilobites lived for millions upon millions of years in ancient seas, so twenty thousand isn’t a huge number. And most of these are only partial specimens. Finding a complete trilobite fossil is still a big moment for a palaeontologist.”
Trilobites first appeared—fully formed, seemingly from nowhere—about 540 million years ago, near the start of the great outburst of complex life popularly known as the Cambrian explosion, and then vanished, along with a great deal else, in the great and still mysterious Permian extinction three million or so centuries later. As with all extinct creatures, there is a natural temptation to regard them as failures, but in fact they were among the most successful animals ever to live. They reigned for 300 million years—twice the span of dinosaurs, which were themselves among history’s great survivors. Humans, Fortey points out, have survived so far for one-half of 1 per cent as long.
With so much time at their disposal, the trilobites proliferated prodigiously. Most remained small, about the size of modern beetles, but some grew to be as big as platters. Altogether they formed at least five thousand genera and sixty thousand species—though more turn up all the time. Fortey had recently been at a conference in South America where he was approached by an academic from a small provincial university in Argentina. “She had a box that was full of interesting things—trilobites that had never been seen before in South America, or indeed anywhere, and a great deal else. She had no research facilities to study them and no funds to look for more. Huge parts of the world are still unexplored.”
“In terms of trilobites?”
“No, in terms of everything.”
Throughout the nineteenth century, trilobites were almost the only known forms of early complex life, and for that reason were assiduously collected and studied. The big mystery about them was their sudden appearance. Even now, as Fortey says, it can be startling to go to the right formation of rocks and to work your way upwards through the aeons, finding no visible life at all, and then suddenly “a whole Profallotaspis or Elenellus as big as a crab will pop into your waiting hands.” These were creatures with limbs, gills, nervous systems, probing antennae, “a brain of sorts,” in Fortey’s words, and the strangest eyes ever seen. Made of calcite rods, the same stuff that forms limestone, they constituted the earliest visual systems known. More than this, the earliest trilobites didn’t consist of just one venturesome species but dozens, and didn’t appear in one or two locations but all over. Many thinking people in the nineteenth century saw this as proof of God’s handiwork and refutation of Darwin’s evolutionary ideals. If evolution proceeded slowly, they asked, then how did he account for this sudden appearance of complex, fully formed creatures? The fact is, he couldn’t.
And so matters seemed destined to remain for ever until one day in 1909, three months shy of the fiftieth anniversary of the publication of Darwin’s On the Origin of Species, when a palaeontologist named Charles Doolittle Walcott made an extraordinary find in the Canadian Rockies.
Walcott was born in 1850 and grew up near Utica, New York, in a family of modest means, which became more modest still with the sudden death of his father when Charles was an infant. As a boy Walcott discovered that he had a knack for finding fossils, particularly trilobites, and built up a collection of sufficient distinction that it was bought by Louis Agassiz for his museum at Harvard for a small fortune—about £45,000 in today’s money Although he had barely a high-school education and was self-taught in the sciences, Walcott became a leading authority on trilobites and was the first person to establish that they were arthropods, the group that includes modern insects and crustaceans.
In 1879 Walcott took a job as a field researcher with the newly formed United States Geological Survey and served with such distinction that within fifteen years he had risen to be its head. In 1907 he was appointed secretary of the Smithsonian Institution, where he remained until his death in 1927. Despite his administrative obligations, he continued to do fieldwork and to write prolifically. “His books fill a library shelf,” according to Fortey. Not incidentally, he was also a founding director of the National Advisory Committee for Aeronautics, which eventually became the National Aeronautics and Space Agency, or NASA, and thus can rightly be considered the grandfather of the space age.
Charles Doolittle Walcott poses before his historic find. Walcott quarried tens of thousands of specimens from the Burgess Shale. (Credit 21.3)
But what he is remembered for now is an astute but lucky find in British Columbia, high above the little town of Field, in the late summer of 1909. The customary version of the story is that Walcott, accompanied by his wife, was riding on a mountain trail when his wife’s horse slipped on loose stones. Dismounting to assist her, Walcott discovered that the horse had turned a slab of shale that contained fossil crustaceans of an especially ancient and unusual type. Snow was falling—winter comes early to the Canadian Rockies—so they didn’t linger, but the next yea
r at the first opportunity Walcott returned to the spot. Tracing the presumed route of the rocks’ slide, he climbed 750 feet to near the mountain’s summit. There, 8,000 feet above sea level, he found a shale outcrop, about the length of a city block, containing an unrivalled array of fossils from soon after the moment when complex life burst forth in dazzling profusion—the famous Cambrian explosion. Walcott had found, in effect, the holy grail of palaeontology. The outcrop became known as the Burgess Shale, from the name of the ridge on which it was found, and for a long time it provided “our sole vista upon the inception of modern life in all its fullness,” as the late Stephen Jay Gould recorded in his popular book Wonderful Life.
Gould, ever scrupulous, discovered from reading Walcott’s diaries that the story of the Burgess Shale’s discovery appears to have been somewhat embroidered—Walcott makes no mention of a slipping horse or falling snow—but there is no disputing that it was an extraordinary find.