Do we like Louis Pasteur?
Our score: 7 out of 10. Nothing harmful turned up and his work saved countless lives, but there's a contested question over how open he was about his methods.
Pasteur is the French chemist who became the face of germ theory. He showed that spoiled food was contaminated from the environment rather than rotting on its own, then moved on to vaccines for chicken cholera, anthrax and rabies. Few scientists can say their work shifted how the whole world thinks about disease.
The showpiece was the 1881 anthrax trial. A vet who doubted Pasteur's germ theory picked the animals, a crowd of officials and journalists watched, and every vaccinated animal survived exposure while unvaccinated sheep and goats died. It was brilliant theatre, and by 1894 an estimated 3.4 million animals had been vaccinated.
Here's the catch. The audience believed they were seeing a live weakened vaccine, but Pasteur's private notebooks, published in the 1970s, show it was a chemically inactivated one, a method pioneered by a rival and improved by his team. Gavi reports he never spelled that out in later years. Historian Gerald Geison made that gap between public and private science the heart of his 1995 book, and he was accused in turn of overegilding small things, with Max Perutz one of his critics.
Then there's rabies. In 1885 Pasteur gave a boy bitten by a dog 13 doses of an experimental vaccine, and the boy did not develop rabies. Geison argued the treatment was experimental and ethically shaky by the standards of the day, while Perutz argued the dog was clearly rabid and Pasteur acted reasonably. A History of Vaccines post notes rabies is fatal once symptoms appear, which is why many see the gamble as justified.
The good stuff is the vaccines themselves, and the sheer scale of the lives they have saved since. The rabies treatment started a new era of vaccination, according to the History of Vaccines project. Whatever the fight over his notebooks, the animals and people protected by this work are very real.
So where does that leave us? We reckon he passes the harm test comfortably, and gets an asterisk on the nice test for the secrecy and the risky human trial. A scientist who fudged the story of how his method worked is a fair thing to side-eye. Still, the end result was a world with far less terror of rabies and anthrax.