A naturalist turns down an offer from Captain Cook

One of humanity’s most important scientific breakthroughs came about as a result of an invitation to go on a voyage, an offer that was accepted (see Captain Robert FitzRoy is in need of a dinner companion). However, it’s also true that one of the most important medical breakthroughs in history only came about because an invitation to go on another great voyage was turned down.

Edward Jenner was a 23-year-old surgeon when he was asked to join Captain James Cook’s second voyage of discovery in 1772. He had worked on material brought back by Cook from his first voyage and was an obvious choice of naturalist to accompany the great explorer on his next journey. This was supposed to settle the argument once and for all as to whether a vast southern land mass – Terra Australis – existed or not. It was a great honour to be asked to take part in such a major expedition, especially one led by such a renowned figure. Along with medicine, natural history was Jenner’s abiding passion, and the voyage was the sort of opportunity that would not only expose him to an exciting array of flora and fauna, but it might also make his name. After agonising over his decision, Jenner opted to eschew life as a full-time naturalist to concentrate on making his career in medicine. ‘I will decline Captain Cook’s offer,’ he declared to his tutor and friend John Hunter. ‘When I was 13 I chose to be a surgeon, and a surgeon I’ll remain.’

He settled down in Berkeley, the small Gloucestershire town where, in 1749, he had entered the world. He was a vicar’s son, the penultimate of nine children, and had begun his career in medicine at the age of 14 – a year after his decision to become a surgeon – when he started his seven-year apprenticeship to a surgeon called Daniel Ludlow in the market town of Chipping Sodbury. This was followed by a couple of years of further training at St George’s Hospital in London. It was here that he came under the tutelage of John Hunter, a surgeon whose radical medical researches led him to carry out pioneering work in the realm of tooth transplants and venereal diseases.

As Berkeley’s resident doctor, Jenner protected the town’s inhabitants from the deadly smallpox virus – which killed about one in three of those who caught it and left horribly scarred those who survived – by practising something called variolation. This involved introducing a very small amount of smallpox-infected material into a patient (usually via a superficial scratch) so that they contracted the disease in a mild enough form to survive it. Once they had recovered, they were henceforth inoculated. It was a technique introduced to Britain from Turkey in 1721 by Lady Mary Wortley Montagu and had been used for hundreds of years in China, Sudan and other countries. Closer to home, a survey conducted in 1791 on the island of Easdale, one of the Slate Islands off the west coast of Scotland, found that the community had freed itself of smallpox by employing just such a system of inoculation. However, there was always a danger that too much of the smallpox virus was given to a patient, leading to death or disfigurement.

As a child Jenner himself had been immunised against smallpox by variolation, and although it had successfully kept him from contracting the full-blown disease, it had had a debilitating effect on his health, a state that he suffered right through adulthood. This was no doubt a spur to his experimentation with immunisation. From his apprenticeship in rural Gloucestershire, he had also been well aware of the snippet of country wisdom that decreed that dairymaids did not catch smallpox. It was believed that this was because they routinely caught cowpox from the cows with which they were so often in close proximity. Cowpox is a disease that is relatively harmless to both cows and humans. In the latter, it merely results in a few unsightly pus-filled spots and a short-lived malaise.

However, it was not until 1796 that Jenner hit upon the idea of testing out this bit of folklore to see if there was anything in it. He got his chance when a patient named Sarah Nelmes came to see him. Nelmes was a dairymaid who was worried that some spots (or ‘pocks’) on her hand might be an early symptom of smallpox. Jenner was able to assure her that it was nothing worse than cowpox (which she had picked up from a cow called Blossom). He then embarked on the sort of experiment that would have medical ethics committees today reaching for their defibrillators. First, he extracted some of the pus from Sarah Nelmes’ hand. Then he looked around for someone who had never suffered from smallpox. An eight-year-old by the name of James Phipps – the son of Jenner’s gardener – was chosen as a guinea pig.

He made a few light cuts in the boy’s arm and introduced some of the pus collected from Sarah Nelmes’ hand. Phipps duly contracted cowpox, recovering from it after a week or so. The truly horrifying element of Jenner’s experiment was yet to come. He variolated his young subject – exposing him to a small dose of smallpox. He could not be sure of the consequences of such a move after a patient had been infected with cowpox from another person (rather than from a cow, as dairymaids caught it). Thankfully for all concerned, the boy did not take ill and die. In fact he did not take ill at all. Jenner was excited – it appeared that the cowpox had made the boy immune to smallpox. The following year, he submitted his work to the Royal Society but was told that he would need to find more evidence to back his claims.

In 1798, after two years of research during which he had successfully repeated his experiment with a score of other children, including his own baby son, Jenner published a book detailing his findings. Clearly with an eye on the bestseller lists, he gave it the snappy title An Inquiry into the Causes and Effects of the Variolae Vaccinae; a Disease Discovered in some of the Western Counties of England, Particularly Gloucestershire, and Known by the Name of the Cow Pox.

In recognition of Jenner’s work, his method eventually became known as ‘vaccination’, a borrowing of the word vacca – meaning ‘cow’ – from Latin. However, the immediate response to his research was far from overwhelming. Indeed, from some quarters it was downright hostile. The anti-vaccination campaigns of our own times – which have been found to be complicit in the resurgence in Britain of childhood diseases such as measles and mumps – are by no means unprecedented. Back in the early 1800s, Jenner’s newfangled vaccinations were challenged by those who were, quite understandably, queasy about a disease that came from cows being introduced into their own bloodstream. Others cited what might be viewed as somewhat confused religious reasons for opposing the procedure. The argument went that humans were God’s greatest creation, and that cows were not on the same plane, and so it was not right that material that had its genesis in the latter be allowed to taint the former, even if the effects were supposedly beneficial. This line of reasoning didn’t explain why it was still apparently morally acceptable for humans to insert much greater quantities of these ‘lower creations’ into their bodies by drinking the secretions of cows and eating virtually every part of them. (Ironically, Jenner was himself a devout Christian.) When cowpox vaccination was eventually made compulsory by law, protests were organised by those who wanted to retain the freedom not to be immunised.

There were many other reasons why Jenner’s book did not start off an immediate revolution in the treatment of smallpox. There was opposition from variolators whose very livelihoods were threatened by his innovation. Furthermore, cross-infection in cowpox doses was sometimes caused by the very people who administered them, since they also came into contact with smallpox sufferers or were treating patients by variolation as well. This could result in people coming down with smallpox immediately after receiving the cowpox vaccine, with the natural lack of confidence in the new practice which that caused.

Jenner valiantly persisted, repeatedly putting forward the case for smallpox vaccination. He worked out more efficient ways of taking pus from the pocks of cowpox sufferers and drying it out so that he could send it off around the world to aid the worldwide struggle against smallpox.

Jenner died of a stroke in 1823, and so never witnessed the immense strides that his methods would take in battling smallpox. It wasn’t until 1840 that Parliament outlawed variolation and it would be another 13 years before The Vaccination Act made cowpox vaccination compulsory for every newborn. This act of Parliament was arguably the first official step taken towards the socialisation of medicine in Britain that would ultimately have its apotheosis in the National Health Service. Furthermore, Jenner’s discovery of vaccines has provided the foundations on which modern immunology is built.

It took an institution with the global reach of the World Health Organisation (WHO) to secure Jenner’s ultimate triumph. A campaign was launched in 1967 with the aim of eradicating smallpox entirely. It was a huge task, given that an estimated 15 million people came down with the disease every year and even the most remote communities were not immune to its grasp. Vaccination programmes were set up in every corner of the planet. It took 12 years but eventually the WHO was able to announce on 26 October 1979 that smallpox had been vanquished.

According to the Jenner Institute, an organisation dedicated to developing innovative vaccines, there are now only two samples of the smallpox virus left in the world, held in laboratories in Siberia and the US and kept under the tightest of security.

Jenner has been fêted all around the globe for his work, both in his lifetime and in the centuries since. Honours and gifts rained down on him from world leaders, including the empress of Russia and Napoléon Bonaparte. Remarkably, as a token of his esteem, Bonaparte released two British non-combatant prisoners of war when Jenner wrote to him requesting such a favour in 1805. Statues of the Gloucestershire doctor have sprung up in cities in all parts of the world, and his former home in Berkeley now hosts a small museum dedicated to his life and work.

Smallpox is the one and only infectious disease ever to have been eradicated by the actions of humans. Captain Cook’s loss has very much been humankind’s gain. However, it didn’t mean that Jenner gave up his natural history research altogether – in fact he was made a fellow of the Royal Society on account of his ornithological work. Cuckoos famously trick other birds into hatching and rearing their offspring, but it was Jenner who was the first to record the fact that a newborn cuckoo, even when still blind, will push any eggs and fledglings out of the nest. By doing so, it secures the full attention of its foster parents and has no rivals for the food they bring to the nest.

Jenner also noticed that the cuckoo is born with a dip in its back that gives it the means to scoop up eggs and chicks. This adaptation disappears by the time the cuckoo is 12 days old. Naturalists were sceptical of Jenner’s findings (which, if nothing else, should have prepared him for the reception of his research on vaccinations) until an artist called Jemima Blackburn witnessed the phenomenon herself. When Charles Darwin saw her illustration and description of the newborn cuckoo, it compelled him to make amendments to his groundbreaking work On the Origin of Species.

There’s a certain delight to be taken from noting that the man whose breakthrough hinged on his taking of a voyage was influenced by the work of a man whose defining moment depended on him not taking one.