Google turned its homepage into a living petri dish today in honor of the 161st birthday of Julius Richard Petri, the German microbiologist who developed the technology.

Google.com currently features six petri dishes colored to match the search giant's familiar logo. Click the play button and a hand swabs each of the dishes before bacteria grows in the shape of the word "Google." Once the name appears, hover over each letter to see where the samples were collected: a smelly sock (left), a doorknob, a keyboard, a dog, a flower in a rainy garden, and a sponge.

Petri was born in Barmen, Germany and originally embarked on a career as a physician. But in 1877, he joined a research facility known as Kaiserliches Gesundheitsamt, where he was a lab assistant to Robert Koch, according to his biography. There, his interest in microbiology grew, and he ultimately developed the shallow dishes that came to be known as petri dishes.

As noted by Encyclopedia.com, bacteria was cultured in liquid broth before the invention of the petri dish. "In an effort to devise a solid medium, Koch experimented with slabs of gelatin positioned on glass or inside bottles," the site said. "Petri realized that Koch's idea could be realized by pouring molten agar into the bottom of a dish and then covering the agar with an easily removable lid."

With the advent of the petri dish, scientists could more easily monitor and study samples in labs and under microscopes.

During his career, Petri also worked with tuberculosis patients, at the Museum of Hygiene in Berlin, and ultimately returned to Kaiserliches Gesundheitsamt as its director in 1889.

Petri died in Zeitz, Germany in 1921.

For more of Google's doodles, see the slideshow below. Recently, the search giant has honored graphic designer Saul Bass, Ella Fitzgerald, Hitchhiker's Guide author Douglas Adams, African singer and activist Miriam Makeba, Nicolaus Copernicus, ferris wheel creator George Ferris, and baseball legend Jackie Robinson.