Pasteur: how they milked a legend

He was a savant and - to most people - a saint. He was also a bit of a sinner, says Bernard Dixon

An innovator with no medical qualifications treats patients with material of uncertain composition and toxicity that he has not tested on animals. He keeps treatment details secret, preventing others from confirming or refuting its value. But he does publish patients' names and addresses (without consent) to publicise his astounding claims. Some patients die, and a close collaborator, a medical doctor, disassociates himself from the work.

It seems astonishing that the perpetrator of these seemingly reckless efforts at rabies vaccination, more than a century ago, is universally recognised as one of the greatest scientists who ever lived. In France he enjoys a status close to sainthood.

Louis Pasteur, who died on 28 September 1895, aged 72, richly deserves his place in the pantheon of science. The ideas behind several of his fundamental discoveries lie at the heart of modern biology, while his development of vaccines against rabies and anthrax not only revolutionised our capacity to combat these diseases but laid down principles of immunisation that are used to save countless lives today. Yet recent revelations about the way Pasteur conducted his research are altering our perceptions of the hero of French, and indeed world, science.

Even in his own age, the range of Pasteur's achievements was extraordinary. Take two examples. He conducted experiments to settle the hotly contested issue of the so-called spontaneous generation of life. He placed a dilute soup of nutrients inside flasks designed to prevent airborne microbes from getting inside, heated them to kill existing microbes, and showed that living cells did not arise from these non-living materials. Microbes grew in the soup only if allowed access from the air.

Second, Pasteur's painstaking studies revealed that tartaric acid consisted of two types of crystal, mirror-images of each other. A startling discovery in its own right, this launched the discipline of stereochemistry, which deals with the "handedness" of crystals and their constituent molecules.

Despite the apparent diversity of these researches, the French chemist's career had a coherence centred on the distinctiveness of living processes. Pasteur was fascinated by the chemistry of life. His primary legacy was to show how particular microbes brought about corresponding, specific changes - whether in fermenting sugar to make alcoholic beverages or in causing disease. Applied to infections, this idea became known as specific aetiology, and is one of the central concepts of 20th-century medicine.

Pasteur also established that there need be no distinction between pure and applied science. In 1865 he saved the French silkworm industry, which was being destroyed by a disease called pebrine. Yet in working out how to prevent its transmission, he was both applying and developing the principle of specific aetiology.

Before being called in to deal with pebrine, Pasteur had established that the "lactic fermentation" (souring of milk) was caused by microbes, which he saw under the microscope. Then, after the silkworm diversion, he proved that other microbes (yeasts) were also responsible for fermentation in brewing and wine-making. Equally important, he discovered what went wrong when fermentation yielded unsatisfactory products - such as "ropey beer". Such undrinkable beers contained a particular microbe that had contaminated the process and caused it to go awry. Pasteur spotted one such organism during a visit to Whitbread's brewery in Clerkenwell, London, in 1871. Shortly after, Whitbread purchased a microscope to help to detect contamination at an early stage.

Specific aetiology was a revolutionary notion at the time and was crucial for the emergence of the germ theory of disease. It meant, for example, that the bacterium Mycobacterium tuberculosis, no other, was responsible for tuberculosis. Only Bacillus anthracis caused anthrax. And so on. A corollary to this discovery was that similarly targeted vaccines might be used to immunise people against particular diseases. Pasteur's innovation was to develop vaccines by weakening microbes so that they induced the recipient to produce specific antibodies but did not cause the disease.

Following Pasteur, other investigators extended specific aetiology in many other directions. First, they found that microbes such as the bacterium responsible for diphtheria caused disease only if they produced particular poisons that damaged the body in various ways. Then other conditions were related to the absence of specific substances - diabetes and insulin being the classic example. All of this originated with Louis Pasteur. It was he who finally swept away the ancient idea, still alive when he began his work in the mid-19th century, that diseases were attributable to imbalances between the four humours of the body.

While Pasteur's achievements were extraordinary, they have been gilded beyond belief over the years. "Here was a life, within the limits of humanity, well nigh perfect," wrote his biographer Stephen Paget in 1910. Two decades later, Paul de Kruif in Microbe Hunters and the actor Paul Muni in the Metro-Goldwyn-Mayer film The Story of Louis Pasteur portrayed the French chemist as a miracle worker. Apart from occasional suggestions by historians of science that some of his results were too good to be true, the legend of Pasteurian perfection has endured, especially in France.

The Princeton University historian Gerald Geison has now brought greater realism to the story in his book The Private Science of Louis Pasteur (Princeton University Press, pounds 24.95). He has done so by scrutinising the 10,000 or so pages of Pasteur's notebooks, which remained in the hands of the Pasteur family until recently, but can now be consulted in the Bibliotheque Nationale in Paris.

What these and other previously neglected sources show is a Pasteur who was all too human. His determination was matched by selfishness and secrecy, his vision accompanied by a tendency to evidence to fit his expectations. Pasteur did offend against the ethical standards of his day (let alone ours) in his work with rabies vaccine - though Geison invites us to judge him leniently in light of the horror surrounding the disease at that time.

Pasteur also concealed the fact that the anthrax vaccine, used to protect sheep in a dramatically successful demonstration in June 1881, was made not by his own method but by that of one of his rivals. In his work on spontaneous generation, Pasteur flouted another central principle of scientific research. He ignored those occasions when living cells did appear, against expectations, in his flasks of nutrient medium. "I did not publish these experiments," he wrote, "for the consequences it was necessary to draw from them were too grave for me not to suspect some hidden cause of error in spite of the care I had taken."

Louis Pasteur was neurotically secretive, too (taking his notebooks on holiday so no one else could consult them). And he was exceedingly difficult to work with. According to Geison, he treated even his most senior colleagues as "toilers in the Pasteurian vineyard ... whose most lasting contribution was their transmission of the Pasteurian legacy to others". Perhaps for this reason, very few of Pasteur's assistants became distinguished scientists. This is in sharp contrast to people such as the physicist Lord Rutherford in Cambridge in the Twenties and Thirties, who spawned virtual dynasties of research leaders.

The final charge against Louis Pasteur is that he was lucky, making far more than one lifetime's worth of original observations, and producing much more precise experimental results than would normally be expected. The charge is hard to deny. Yet his own, oft-quoted observation about scientific research remains the most important single clue to his own genius. "In the field of experimentation," Pasteur said, "chance favours only the prepared mind."

Start your day with The Independent, sign up for daily news emails
News
ebookA unique anthology of reporting and analysis of a crucial period of history
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Guru Careers: Software Developer / C# Developer

£40-50K: Guru Careers: We are seeking an experienced Software / C# Developer w...

Guru Careers: Software Developer

£35 - 40k + Benefits: Guru Careers: We are seeking a Software Developer (JavaS...

SThree: Trainee Recruitment Consultant / Resourcer

£18000 - £23000 per annum + Commission: SThree: As a Trainee Recruitment Consu...

Ashdown Group: UI Developer - (UI, HTML, CSS, JavaScript, AngularJS)

£25000 - £40000 per annum: Ashdown Group: UI Developer - (UI, JavaScript, HTML...

Day In a Page

Sun, sex and an anthropological study: One British academic's summer of hell in Magaluf

Sun, sex and an anthropological study

One academic’s summer of hell in Magaluf
From Shakespeare to Rising Damp... to Vicious

Frances de la Tour's 50-year triumph

'Rising Damp' brought De la Tour such recognition that she could be forgiven if she'd never been able to move on. But at 70, she continues to flourish - and to beguile
'That Whitsun, I was late getting away...'

Ian McMillan on the Whitsun Weddings

This weekend is Whitsun, and while the festival may no longer resonate, Larkin's best-loved poem, lives on - along with the train journey at the heart of it
Kathryn Williams explores the works and influences of Sylvia Plath in a new light

Songs from the bell jar

Kathryn Williams explores the works and influences of Sylvia Plath
How one man's day in high heels showed him that Cannes must change its 'no flats' policy

One man's day in high heels

...showed him that Cannes must change its 'flats' policy
Is a quiet crusade to reform executive pay bearing fruit?

Is a quiet crusade to reform executive pay bearing fruit?

Dominic Rossi of Fidelity says his pressure on business to control rewards is working. But why aren’t other fund managers helping?
The King David Hotel gives precious work to Palestinians - unless peace talks are on

King David Hotel: Palestinians not included

The King David is special to Jerusalem. Nick Kochan checked in and discovered it has some special arrangements, too
More people moving from Australia to New Zealand than in the other direction for first time in 24 years

End of the Aussie brain drain

More people moving from Australia to New Zealand than in the other direction for first time in 24 years
Meditation is touted as a cure for mental instability but can it actually be bad for you?

Can meditation be bad for you?

Researching a mass murder, Dr Miguel Farias discovered that, far from bringing inner peace, meditation can leave devotees in pieces
Eurovision 2015: Australians will be cheering on their first-ever entrant this Saturday

Australia's first-ever Eurovision entrant

Australia, a nation of kitsch-worshippers, has always loved the Eurovision Song Contest. Maggie Alderson says it'll fit in fine
Letterman's final Late Show: Laughter, but no tears, as David takes his bow after 33 years

Laughter, but no tears, as Letterman takes his bow after 33 years

Veteran talkshow host steps down to plaudits from four presidents
Ivor Novello Awards 2015: Hozier wins with anti-Catholic song 'Take Me To Church' as John Whittingdale leads praise for Black Sabbath

Hozier's 'blasphemous' song takes Novello award

Singer joins Ed Sheeran and Clean Bandit in celebration of the best in British and Irish music
Tequila gold rush: The spirit has gone from a cheap shot to a multi-billion pound product

Join the tequila gold rush

The spirit has gone from a cheap shot to a multi-billion pound product
12 best statement wallpapers

12 best statement wallpapers

Make an impact and transform a room with a conversation-starting pattern
Paul Scholes column: Does David De Gea really want to leave Manchester United to fight it out for the No 1 spot at Real Madrid?

Paul Scholes column

Does David De Gea really want to leave Manchester United to fight it out for the No 1 spot at Real Madrid?