TODAY'S Google Doodle celebrates Danish microbiologist Hans Christian Gram.
But who was he and what did he discover?
Hans Christian Gram was a Danish microbiologist who Google is celebrating today with a Google on his 166th birthdayCredit: Alamy
Who was Hans Christian Gram?
Hans Christian Gram was a Danish microbiologist who Google is celebrating today on his 166th birthday.
The doodle that honours Gram on his birth anniversary today was illustrated by Danish guest artist Mikkel Sommer.
Gram was born in Copenhagen on September 13, 1853, and died in his home city on November 14, 1939, aged 86.
He was the son of Frederik Terkel Julius Gram, a professor of jurisprudence, and Louise Christiane Roulund.
The microbiologist studied at the University of Copenhagen and was an assistant in botany to the well-known Danish zoologist Japetus Steenstrup.
His study of plants introduced him to the fundamentals of pharmacology and the use of the microscope.
Gram then enrolled in medical school in 1878, before graduating in 1883.
He went travelling throughout Europe to study bacteriology and pharmacology between 1878 and 1885 after graduating.
In 1891, Gram taught pharmacology, and later that year was appointed professor at the University of Copenhagen.
In 1900, he resigned his chair in pharmacology to become professor of medicine.
The doodle that honours Gram on his birth anniversary today was illustrated by Danish guest artist Mikkel SommerCredit: Google
What did he discover?
In Berlin, in 1884, Gram developed a method for distinguishing between two major classes of bacteria.
This technique, the Gram stain, continues to be a standard procedure in medical microbiology to this day.
His initial work involved the study of red blood cells in men.
Gram was among the first to recognise that macrocytes were characteristic of pernicious anaemia.
He was later appointed as a professor of medicine at the University of Copenhagen in 1900 after resigning from pharmacology.
During his career as a professor, he published four volumes of clinical lectures which became widely used in Denmark.
He retired from the University of Copenhagen in 1923.
What is a Google Doodle?
In 1998, the search engine founders Larry and Sergey drew a stick figure behind the second 'o' of Google as a message to that they were out of office at the Burning Man festival and with that, the art of the Google Doodle was born.
The company decided that they should decorate the logo to mark cultural moments and it soon became clear that users really enjoyed the change to the Google homepage.
Now, there is a full team of doodlers, illustrators, graphic designers, animators and classically trained artists who help create what you see on those days.
Google kicked off 2019 with an animated Doodle of New Year's Eve celebrations.
And on February 5, 2019, the Chinese New Year was celebrated with a hand animation transforming into a pig.
St Patrick's Day on March 17 was remembered with a Celtic Google Doodle.
And on March 21, Google Doodle used AI for the first time in a tribute to Johann Sebastian Bach.
The Doodle allowed users to create their own tune.
And Google also celebrated the Women's World Cup with Doodles for each participating team.