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Creation Date



Rebecca Craighill in 1914

Courtesy of the Rockefeller Archive Center

Rebecca C. Lancefield (Criaghill) was a bacteriologist who joined Rockefeller in 1918 as a technical assistant and retired 60 years later as a professor. She famously devised a system for classifying subtypes of streptococcal bacteria. At the time of her investigations, the United States had entered WWI and strep infections were a scourge on military bases; but scientists did not know what strains of bacteria were responsible for these outbreaks or how animal and human strep differed from each other. Lancefield’s approach to classification helped answer these questions and remains a ubiquitous part of American medical education. Her research also laid the groundwork for understanding a variety of diseases, including scarlet fever and acute kidney disease.


Rebecca Craighill (Lancefield), bacteriology, streptococcal bacteria, scarlet fever