The author relates the progress of inoculation against smallpox in America with the interaction between an African slave named Onisimus whose homeland knew how to treat the malady and and leading clergyman Cotton Mather who was curious and open-minded enough to listen to him.

The professor counsels against retrospective history, assuming that particular pieces contributed to an outcome.

Manners matter, asserts the professor. What provokes rebellion, he asserts, is not as often a theory out allowing for arbitrary power but be excessive, brusque use of it by a particular individual.