By Andrew Cunningham
Radio 4's Making of Modern Medicine
Modern medicine's achievements in countering illness and mortality owe their origins to a scientific revolution in France 200 years ago.
The stethoscope helped one doctor detect TB
In the very early 1800s, in the wake of the French Revolution, a group of energetic and influential medics based mainly around Paris, became the pioneers of modern medicine.
Their aim was to reform medicine along the lines that physics and chemistry had been developed in the course of the 18th century - to give it a scientific basis.
Medicine was now to be based on experiment and observation, and to rely on the senses rather than the imagination when looking for causes.
In other words, they gave medicine a typically Enlightenment treatment.
And their reforms were very successful, in part because they could work together, rather than as isolated individuals.
Parisian 'guinea pigs'
The white heat of the French Revolution allowed individuals to question the basis of everything, not just political structures but every part of life.
And it put in power the men who could apply that to medicine.
The chemist Antoine Fourcroy announced to France's new law-making body, the Convention in 1794 how medicine would be taught: "Little reading, much seeing and much doing will be the foundation of the new teaching which your committee proposes.
"Practising the art, observing at the bedside, all that was missing, will now be the principal part of instruction."
And Paris, with its dense population was an ideal place for the advances to take place.
The hospitals of Paris were the great sheltering places for the poor, homeless and sick.
They turned them into exclusively medical institutions, and used the thousands of poor people in them as their guinea-pigs.
Post mortem clues
Doctors carefully watched the course of their patients' diseases.
Jean-Nicolas Corvisart was able to detect aneurysms in arteries
As well as observing and recording visible symptoms they carried out manual examinations, along with newer techniques.
At the hospital of La Charité, the physician Jean-Nicolas Corvisart pioneered tapping on the chest to analyse heart disease.
One of his pupils, Théophile Laennec invented the stethoscope and was able to diagnose consumption.
He said: "I began to suspect that the phenomenon could be due to cavities in the lungs produced by the softening of the tubercules.
"As most of the patients who presented this phenomenon died at the hospital, I was able to confirm at autopsy that my suspicion was correct."
The widespread use of post mortems allowed the scientific classification of disease for the first time. Along with the symptoms, the doctors were able to see what had been going on inside bodies during the course of the illness.
They also created laboratories, as the physicists and chemists had done, and in them they tested and tortured nature to try to work out how animal and human bodies work and how and why they malfunction, sacrificing millions of animals to this cause.
Their ideas spread across Europe and to America, with medical schools established alongside hospitals. But some of the advances came at a heavy cost.
At the Imperial General Hospital in Vienna, a young obstetrician called Ignaz Semmelweis was struggling to understand a dramatic rise in deaths from childbed fever.
Early versions of the stethoscope
He studied the symptoms of the patients and carried out autopsy after autopsy.
Eventually and tragically he discovered he himself was transporting the condition. But Semmelweis was effectively introducing into medicine a new meaning for "cause" in disease that none of his contemporaries shared and which would later transform medical thinking and practice.
Later in the 19th century investigators, such as Louis Pasteur established laboratories to investigate the minute causes of infectious disease: the germs.
The result was new and reliable forms of diagnosis, a far better understanding of the workings of the human body and its weaknesses, and cures for diseases as well as ways - especially with vaccines - of protecting people from illnesses in the first place.
The events of the French Revolution triggered a big-bang which completely transformed medicine.
The foundations laid by Laennec, Corvisart and others opened the door to allow scientists to discover much more about how and why people become ill and what can be done to treat and cure them.
The Making of Modern Medicine is on Radio 4 every weekday at 1545 GMT from Monday 5 February to Friday 16 March.
The series tracing the entire history of medicine is written and presented by Andrew Cunningham, Senior Research Fellow in the Department of History and Philosophy of Science, Cambridge University.