Smallpox has been one of the deadliest diseases known to humankind.
In 16th c. New England, over 50% of Native peoples died of the disease. In the 20th c., smallpox killed 300 million people - more than died in all of that century's wars. The disease was finally eradicated in 1979.

Smallpox entered a community through the arrival of an infected person and stayed until most people had been infected - and lived or died. Until inoculation, immunity came only to those who came down with and survived the disease.

In Boston's early history, smallpox ravaged the city every twenty years or so. In 1678, roughly 700 out of Boston's population of 4000 died - 1 in 6 people. History shows that an African man provided key scientific knowledge on this deadly disease, while two other Africans played key roles in confirming that knowledge.

Reverend Cotton Mather, Puritan leader and scholar, searched widely for a means to stop smallpox. Wanting to know the risks to members of his household when smallpox returned, Mather asked his enslaved man, Onesimus, whether he'd had smallpox, to which Onesimus answered 'yes' and 'no'.
Onesimus went on to explain to the startled Mather that, yes, in Africa his mother had pricked his arm with a tiny amount of smallpox so that no, he did not and could not get the full disease. (more information on Onesimus)
Surprised, Dr. Mather sought out other first generation Africans, some of whom confirmed Onesimus' account - and African knowledge.
A few years later, Mather read that Turks were also using inoculation effectively.

In 2003, The New Yorker published the poem below, by poet Susan Donelly:


Cotton Mather studied smallpox for a while,
instead of sin. Boston was rife with it.
Not being ill himself, thank Providence,
But one day asking his slave, Onesimus
If he'd ever had the pox. To which Onesimus replied,
"Yes and No." Not insubordinate
or anything of the kind, but playful, or perhaps
musing, as one saying to another:
"Consider how a man
can take inside all manner of disease
and still survive."

Then, graciously, when Mather asked again:

My mother bore me in the southern wild.
She scratched my skin and I got sick, but lived
To come here, free of smallpox, as your slave.

Rev. Mather shared his discoveries with his friend and colleague, Dr. Zabdiel Boylston, of Brookline (an image of the main fragment of his tombstone is below).Tomb of Zabdiel Boylston

In 1721 smallpox broke out again in Boston and Brookline. Dr. Boylston immediately began his experiment with inoculation. He gave a small dose of the disease simultaneously to 3 people in his home: his slave Jack, Jack's 2-year-old son Jackey, and Dr. Boylston's own son Thomas, whom Dr. Boylston described as "about six". (ref.: Boylston, Zabdiel, An Historical Account of the Small-pox Inoculated in New England: upon All Sorts of Persons, Whites, Blacks and of All Ages and Constitutions; with Some Account of the Nature of the Infection in the Natural and Inoculated Way, and Their Different Effects on Human Bodies." Printed for S. Chandler, at the Cross-Keys in the Poultry, London, 1726.)

All 3 sickened but survived.
So Dr. Boylston began inoculating others.
However, a great outcry arose opposing his work, especially among other clergy. By the time the epidemic had waned, Dr. Boylston had inoculated 274, of whom 6 died - fewer than 2%.
Out of the general Boston population, 15% of those who came down with the disease died. Dr. Boylston's experiment's had succeeded and led to the widespread use of inoculation.

Dr. Boylston grew up and lived part of his life in Brookline, where he is buried.
His home still stands across from the Brookline Reservoir. The image above shows the main fragment of Dr Boylston's tombstone in the Walnut St Cemetery, Brookline. Dr. Boylston is buried here along with several of his descendants and one of his enslaved men, named Boston.