in 1721, Boston doctor Zabdiel Boylston took a gamble with his young son’s life and inoculated him against smallpox. Puritan minister Cotton Mather had learned from one of his slaves that in Africa people did not fear the disease that so terrified Europeans. The Africans placed a small amount of smallpox pus into a scratch on children’s arms, thus making them immune to the disease. When an epidemic broke out in Boston in 1721, Mather wanted to try this method. He convinced Dr. Boylston, but other physicians and the public thought the idea barbaric, even sinful. However, when those Boylston inoculated survived, the tide of public opinion began to turn. Within a few years, the once-controversial practice would be routine.
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An epidemic occurred “on schedule” in 1702 and then, for some unknown reason, not again in Boston for 19 years. As more and more children grew to maturity without being exposed to the pox, Bostonians knew that when the disease did return, it would be more devastating than ever before.
Cotton Mather, the minister famous for his role in the witchcraft trials had watched three of his children nearly die in earlier epidemics. In 1706 he acquired a slave named Onesimus. This African-born man had no fear of smallpox. In his homeland, he told Mather, a little pus from an infected person was inserted into a cut made in the skin of a healthy person. The healthy person usually got a mild case of the disease and soon recovered; exposure to smallpox later in life had no ill effect.
Other African slaves told similar stories, and Rev. Mather became as confident of the safety and success of this operation as he was “that there are Lions in Africa.” A decade later, Mather read two different accounts from doctors in Turkey who had discovered that the same method was followed in the eastern Mediterranean. He was convinced that the practice was sound.
American Slave and Racism Horrors: 1492 - 2000s 
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