尽管相对少见，狂犬病（又名“恐水症”）在欧洲引起了极大的恐慌；患者口吐白沫，非常痛苦、惨烈地死去。但病毒的潜伏期也使巴斯德——已经是法国非常著名的科学家——对狂犬病成为一种新型疫苗的候选对象产生了兴趣。

On July 6, 1885, three men in Paris prepared to treat Joseph Meister, a nine-year-old from Alsace who had been bitten multiple times by a rabid dog. Two of the men were medically trained; the third was the therapy’s creator, a chemist-turned-microbiologist named Louis Pasteur.

Despite being relatively rare, rabies (or hydrophobia, as it was also known) commanded a fearful fascination in Europe; wildly foaming at the mouth, its victims died painfully and dramatically. But the virus’s incubation period also made rabies of interest to Pasteur—already a famous scientist in France—as a candidate for a new type of vaccine.

By 1885, five years after starting work on rabies, Pasteur and his colleagues had developed a live viral preparation, which, Pasteur claimed, not only protected dogs from rabies infections, but prevented the disease from becoming symptomatic if administered postexposure.

Still, it was not without reluctance—or concern from his peers—that he agreed to administer a series of viral injections to the asymptomatic young Meister. “This will be another bad night for your father,” wrote Pasteur’s wife Marie to their children during the treatment. “He cannot come to terms with the idea of applying a measure of last resort to this child.”

But it seemed to work—Meister didn’t develop rabies. And after starting treatment of another boy that October, Pasteur declared the vaccine a success before the French National Academy of Medicine. 

The story became international news; even patients from America were soon shipped over to Europe to receive the miracle cure.