Boylston inoculates three people in Boston

His dated letter reported living “animalcules” in pepper water and water from different sources.

Leeuwenhoek sent his observations to Henry Oldenburg in London for discussion at the Royal Society.

The letter compared well, rain, sea and other waters through a microscope; identification of individual species came later.

The 9 October account became important to the later history of microbiology, although it was not yet a theory of infectious disease.

Jack and his young son Jackey were enslaved by Boylston; their participation in this experiment must not be portrayed as freely chosen.

Onesimus, enslaved by Cotton Mather, had earlier described an African inoculation method that shaped advocacy during the epidemic.

Boylston treated his own son and two people he enslaved, while Asian, African and Ottoman variolation practices long predated Boston’s experiment.

Jenner transferred material from milkmaid Sarah Nelmes’s cowpox lesion to the eight-year-old boy.

Sarah Nelmes supplied the cowpox material used in the experiment; she should be included in the account of the procedure.