In 1721, a devastating smallpox epidemic struck Boston. Nearly half its residents fell ill. Hundreds died. In his diary, the Rev. Cotton Mather wrote that the town had become almost a "Hell upon Earth.”

Onesimus, an African man sold into slavery to Mather, recalled a method he had witnessed in Africa: Inoculating healthy people with a small amount of infectious material would produce only a mild infection, and make them immune to the disease.

Onesimus’ method, termed variolation, predated Edward Jenner’s experiments using a milder virus, cowpox, to vaccinate against smallpox in 1796. But Mather believed Onesimus. The preacher used his influence to promote variolation ‒ and was derided for it. He finally persuaded a doctor named Zabdiel Boylston to perform it. The technique saved hundreds of lives.

This American story illustrates a recurring pattern of medical progress. A new idea is disparaged as heretical, and the true-believing maverick must endure ridicule to demonstrate its worth. Finally, sometimes after decades, acceptance is achieved. This pattern repeats, but not in a predictable or linear fashion. Innovation can emerge from unlikely sources and often depends on individualists willing to act before possessing full knowledge of why their intervention actually works.

National Doctors' Day honors physicians and medical innovators

National Doctors’ Day, observed on March 30, is designated to commemorate........

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