"Documentation of variolation in the Americas may be traced back to 1706 in Boston, where Puritan minister Cotton Mather learned of the technique from his West

"Documentation of variolation in the Americas may be traced back to 1706 in Boston, where Puritan minister Cotton Mather learned of the technique from his West African slave Onesimus.[3]:45 Further research into the matter revealed to Mather that several other slaves had too been variolated." https://en.wikipedia.org/wiki/Variolation https://en.wikipedia.org/wiki/Variolation