Google is honoring the scientist who spent his life studying germs and how they cause infectious disease.
On Sunday, Google transformed its logo into a tribute for Robert Koch, who received the Nobel Prize on this day in 1905.
As Google explains, Koch identified the bacterium for diseases including anthrax, cholera and tuberculosis.
Koch is also credited with sparking a "Golden Age of bacteriology," during which scientists discovered the causes behind 21 diseases.
"Perhaps better than anyone else at the time, Koch understood that sometimes the keys to solving big problems lay in their microcosms," wrote Google in a blog post explaining Sunday's doodle.
The doodle features potato slices, used by Koch as part of his research. The doodle also features a Petri dish with Koch's name. According to Google, Julius Petri, its inventor, worked as Koch's assistant.
Koch died in 1910, five years after receiving the Nobel, according to a biography on the Nobel Prize website.
Follow Brett Molina on Twitter: @brettmolina23.
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