Hans Christian Joachim Gram (13 September 1853 - 14 November 1938) was a Danish bacteriologist who developed the Gram stain, still a standard technique to classify bacteria and visualize them under a microscope.

Early life and education

Gram was the son of Frederik Terkel Julius Gram, a professor of jurisprudence, and Louise Christiane Roulund.

He studied at the University of Copenhagen,

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