"Before 1721, smallpox was virtually a deadly disease with no real cure, and very highly feared. During the late seventeen-teens, Cotton Mather, the fundamentalist Puritan minister heard of an old African procedure as a preventative for smallpox from one of his slaves who described to him a crude method of Lady Mary's ingrafting which had been performed in Africa for many years."

SMALLPOX IN THE 18th CENTURY
Susan Pryor, 1984
Research Report
Colonial Williamsburg Foundation - 0201