Fanny Hesse's Agar Revolutionized Microbiology

In 1881, American-born scientific illustrator Fanny Angelina Hesse suggested that her husband, German physician Walther Hesse, replace the gelatin in his microbe experiments with agar, a jelly ingredient from her kitchen. Gelatin melted in the summer heat and could be consumed by microbes, while agar stayed solid at high temperatures and resisted degradation. Walther shared the idea with German bacteriologist Robert Koch, who used agar in his research but failed to credit the Hesses when he discussed it in 1882. Agar became essential in laboratories worldwide, yet Fanny received little recognition for introducing it to microbiology.

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