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. He 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.
He published these findings the very same year in a scholarly journal and included a modest disclaimer that his findings are defective and imperfect but he hoped it would turn out to be useful in the hands of future investigators.
More than a century later, Gram’s simple staining method, named after its inventor, is still widely used.
Gram showed a keen interest in the clinical education of students throughout his career. He retired from his medical practice in 1923 and died at the age of 85 in 1938.
The Doodle is illustrated by Danish guest artist Mikkel Sommer who is based between Athens and Berlin.