Puritan clergyman, investigator of withchcraft, and early proponent of vaccination. Cotton Mather is probably best remembered in history for his role in the Salem witch trials of 1692-93. Although he publicly supported some of the executions, Mather opposed admitting the spectral evidence brought against many of the accused. Instead, he recommended prosecution only for cases based on solid evidence, and execution only in extreme cases. Mather investigated some witchcraft cases personally; in 1688 he took a witch-child into his own house, recording his observations of her behavior in Memorable Providences, Relating to Witchcrafts and Possessions (1689). Despite his relatively liberal views on the subject, Mather supported the Salem verdicts in books such as Wonders of the Invisible World (1693). He also supported the Salem judges against one of their harshest critics, Robert Calaf, who expressed skepticism about the existence of witchcraft with his book, More Wonders of the Invisible World (1700).
Mather was also a corresponding member of the Royal Society of London and an early proponent of vaccination. In 1721, the city of Boston was ravaged by a great smallpox epidemic. Mather, exposed to the idea of vaccination through his Royal Society associates, interested Dr. Zabdiel Boylston in the practice. However, most of the community of Boston, the majority of the towns physicians, and some of the town’s clergy opposed the process. Their fears were in part grounded in fact: At that time, a person was inoculated by introducing material directly from an infected wound into an open wound on another person. This process, however, made the inoculated person potentially as contagious as anyone who was not infected with the disease on purpose.