In 1716, a man from west Africa named Onesimus was enslaved to Puritan minister Cotton Mather in Boston. Onesimus shared the variolation technique against smallpox with Mather. This effective technique was eventually adopted widely in both the colonies and Western Europe.
Mather and physician Zabdiel Boylston experimented with the variolation technique in 1721, inoculating their families and those enslaved by them. They wrote about their work in a pamphlet, An Historical Account of the Small-pox Inoculated in New England.
London: Printed for S. Chandler, at the Cross-Keys in the Poultry, MDCCXXVI [1726]; [Boston in N.E.]: Re-printed at Boston in N.E. for S. Gerrish in Cornhil, and and T. Hancock at the Bible and Three Crowns in Annstreet, MDCCXXX [1730].