There is no picture of Onesimus. Artist , Jean-Louis André Théodore Géricault, Portrait of a Black Man, France (c. 1823), Oil on Canvas

Inoculation was introduced to America by a slave

Onesimus (fl. 1706 – 1717), was a slave and medical pioneer. Few details are known about the birth of Onesimus, but it is assumed he was born in Africa,  in the late seventeenth century, although the precise date and place of his birth are unknown, before eventually landing in Boston. 

Onesimus 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.

When asked if he’d ever had smallpox, Onesimus answered “Yes and No,” explaining that he had been inoculated with a small amount of smallpox, which had left him immune to the disease. Fascinated, Mather asked for details, which Onesimus provided, and showed him his scar. 

Onesimus told Mather about the centuries old tradition of inoculation practiced in Africa. By extracting the material from an infected person and scratching it into the skin of an uninfected person, you could deliberately introduce smallpox to the healthy individual making them immune.

Onesimus was one of about a thousand persons of African descent living in the Massachusetts colony in the early 1700s, one-third of them in Boston. Many were indentured servants with rights comparable to those of white servants, though an increasing number of blacks–and blacks only–were classified as chattel and bound as slaves for life.

Excited, he investigated among other Africans in Boston and realized that it was a widespread practice; indeed, a slave could be expected to fetch a higher price with a scar on his arm, indicating that he was immune. 

Mather's writings suggest that, more than most of his contemporaries, he admired Africans, but he also accepted slavery, and had raised no objections when his congregation presented him with a young slave in 1706. 

What Onesimus thought of Mather’s opinions the historical record does not say, nor do we know much about his family life other than that he was married and had a son, Onesimulus, who died in 1714. Two years later Onesimus gave the clearest indication of his attitude toward his bondage by attempting to purchase his release from Mather. To do so, he gave his master money toward the purchase of another black youth, Obadiah, to serve in his place.

Mather probably welcomed the suggestion, since he reports in his diary for 31 August 1716 that Onesimus “proves wicked, and grows useless, Froward [ungovernable] and Immorigerous [rebellious].” Around that time Mather signed a document releasing Onesimus from his service “that he may Enjoy and Employ his whole Time for his own purposes and as he pleases” (Mather, vol. 2, 363). However, the document makes clear that Onesimus’s freedom was conditional on performing chores for the Mather family when needed, including shoveling snow, piling firewood, fetching water, and carrying corn to the mill. This contingent freedom was also dependent upon his returning a sum of five pounds allegedly stolen from Mather.

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.

Considered extremely dangerous at the time, Cotton Mather convinced Dr. Zabdiel Boylston to experiment with the procedure when a smallpox epidemic hit Boston in 1721 and over 240 people were inoculated. Opposed politically, religiously and medically in the United States and abroad, public reaction to the experiment put Mather and Boylston’s lives in danger despite records indicating that only 2% of patients requesting inoculation died compared to the 15% of people not inoculated who contracted smallpox. Boylston successfully variolate 300 patients with only six of them dying. By contrast, 1,000 of the 6,000 people who acquired smallpox naturally died during the same period.

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. Boylston traveled to London in 1724. There he published his results and was elected to the Royal Society in 1726.

Onesimus’ traditional African practice was used to inoculate American soldiers during the Revolutionary War and introduced the concept of inoculation to the United States and variolation remained the most effective means of treating the disease until the development of vaccination by Edward Jenner in 1796.

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.

Further Reading

Herbert, Eugenia W. “Smallpox Inoculation in Africa.” Journal of African History 16 (1975).
Mather, Cotton. Diary (1912).
Silverman, Kenneth. The Life and Times of Cotton Mather (1984).
Winslow, Ola. A Destroying Angel: The Conquest of Smallpox in Colonial Boston (1974).


Part of the Court.rchp.com 2017 Black History Month Series


Compiled under fair use exemption, from material originally published by Harvard's Hutchins Center for African & African-American Research and PBS.

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