Google celebrates 166th birth anniversary of The man who dis
Google is celebrating the 166th birth anniversary of microbiologist Hans Christian Joachim Gram with a doodle.

Gram was born on September 13, 1853, in Denmark’s Copenhagen. Gram is best known for pioneering the method of the Gram stain to identify bacteria.

The Danish microbiologist earned an M.D. from the University of Copenhagen in 1878. He then traveled through Europe between 1883 to 1885 studying pharmacology and bacteriology.

It was in 1884, while working in the lab of German microbiologist Karl Friedländer in Berlin, that he devised his famous staining technique that is now still used to identify and classify different types of bacteria. He followed the method of Paul Ehrlich, using aniline-water and gentian violet solution.

Gram noticed that treating a heat-fixed smear of bacterial cells with a crystal violet stain, followed by an iodine solution and an organic solvent, revealed differences in the structure and biochemical function of various samples.

Gram-positive bacteria remained purple because they have a single thick cell wall that is not easily penetrated by the solvent. While, gram-negative bacteria decolorized because they have cell walls with much thinner layers that allow removal of the dye by the solvent.

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