Onesimus (fl. 1706 – 1717), slave and medical pioneer, was born in the late seventeenth century, probably in Africa, although the precise date and place of his birth are unknown. He first appears in the historical record in the diary of Cotton Mather, a prominent New England theologian and minister of Boston’s Old North Church. Reverend Mather notes in a diary entry for 13 December 1706 that members of his congregation purchased for him “a very likely Slave; a young Man who is a Negro of a promising aspect of temper” (Mather, vol. 1, 579). Mather named him Onesimus, after a biblical slave who escaped from his master, an early Christian named Philemon.
Little is known of Onesimus after he purchased his freedom, but in 1721 Cotton Mather used information he had learned five years earlier from his former slave to combat a devastating smallpox epidemic that was then sweeping Boston. In a 1716 letter to the Royal Society of London, Mather proposed “ye Method of Inoculation” as the best means of curing smallpox and noted that he had learned of this process from “my Negro-Man Onesimus, who is a pretty Intelligent Fellow” (Winslow, 33). Onesimus explained that he had
undergone an Operation, which had given him something of ye Small-Pox, and would forever preserve him from it, adding, That it was often used among [Africans] and whoever had ye Courage to use it, was forever free from ye Fear of the Contagion. He described ye Operation to me, and showed me in his Arm ye Scar.” (Winslow, 33)
Reports of similar practices in Turkey further persuaded Mather to mount a public inoculation campaign. Most white doctors rejected this process of deliberately infecting a person with smallpox–now called variolation–in part because of their misgivings about African medical knowledge. Public and medical opinion in Boston was strongly against both Mather and Dr. Zabdiel Boylston, the only doctor in town willing to perform inoculations; one opponent even threw a grenade into Mather’s home. A survey of the nearly six thousand people who contracted smallpox between 1721 and 1723 found, however, that Onesimus, Mather, and Boylston had been right. Only 2 percent of the six hundred Bostonians inoculated against smallpox died, while 14 percent of those who caught the disease but were not inoculated succumbed to the illness.
It is unclear when or how Onesimus died, but his legacy is unambiguous. His knowledge of variolation gives the lie to one justification for enslaving Africans, namely, white Europeans’ alleged superiority in medicine, science, and technology. This bias made the smallpox epidemic of 1721 more deadly than it need have been. Bostonians and other Americans nonetheless adopted the African practice of inoculation in future smallpox outbreaks, and variolation remained the most effective means of treating the disease until the development of vaccination by Edward Jenner in 1796.
Written By: Steven Niven