Google Doodle Honors Hans Christian Gram on 166th Birth Anniversary

Hans Christian Gram was Danish bacteriologist known for his groundbreaking discovery of the Gram stain.


Google pays a tribute to renowned microbiologist, Hans Christian Gram, on his 166th birth anniversary for his pioneering work in the field of microbiology with a Doodle.

Born on September 13, 1853, in Copenhagen, Denmark, Gram was known for developing a staining technique called “Grain stain.” This technique helps in identifying and characterizing bacteria into Gram-positive and Gram-negative bacteria.

Gram staining enables better visualization of bacteria under the microscope.

He earned his degree from the University of Copenhagen. He worked as a resident doctor in the city’s municipal hospital. Gram then traveled across Europe while exploring his expertise in microbiology and pharmacology.

Gram developed the staining technique while he was working with Karl Friedländer in his Berlin laboratory. The technique includes smearing the bacteria with a violet dry and rinsing it with an organic solvent and iodine solution.

The pathogenic bacteria are classified into Gram-positive and Gram-negative depending on the thickness of the cell wall. If the cell wall is thick and remains purple, the bacteria are considered Gram-positive. If the cell wall is thin and does not retain the stain, they are considered Gram-negative.

Gram dies on November 14, 1938, in Copenhagen, Denmark. He was 85. The Gram stain technique continues to be a standard procedure in microbiology even after eight decades of his death.