Who was Hans Christian Gram? Google Doodle honours pioneering Danish scientist

Dr Hans Christian Gram devised the Gram staining technique which is still used to this day
Tom Herbert13 September 2019

Today's Google Doodle honours the 166th birthday of groundbreaking Danish scientist Hans Christian Gram.

In 1884, Gram created a pioneering technique to distinguish between different types of bacteria.

Known as the Gram stain, the staining technique continues to be used as standard procedure in medical microbiology more than a century later, cementing his legacy as a visionary scientist.

Here's all you need to know about today's Google Doodle, Hans Christian Gram.

Hans Christian Gram would have celebrated his 166th birthday today
Google

Who was he?

Born in Copenhagen on September 13, 1853, Gram enrolled at the University of Copenhagen where he was an assistant in botany to zoologist Japetus Steenstrup.

After earning his MD in 1878, he worked at various hospitals in the Danish capital before travelling throughout Europe to further his studies in bacteriology and pharmacology.

It was during his time working in the lab of the German microbiologist Karl Friedländer that he devised his famous microbiological staining technique.

He published his findings in 1884 and spent the next few years working as a hospital assistant before he was appointed professor of pharmacology at the University of Copenhagen in 1891.

In 1900, Gram resigned his pharmacology chair to take up a role as professor of medicine, which he held before retiring in 1923. He died in Copenhagen in 1938 aged 85.

What did Dr Gram discover?

It was while working in Germany that Gram discovered a method of staining bacteria which would make them more visible under a microscope.

Gram noticed that if he treated a smear of bacteria with a crystal violet dye, before rinsing it in an iodine solution and an organic solvent, he could reveal differences between samples.

He found that bacteria with a thick cell wall would remain purple because the solvent could not wash the dye away, and were known as "Gram-positive".

But rinsing thinner-walled bacteria with the solvent solution would wash the stain away, meaning they would not remain purple. These types of cells are known as Gram-negative.

In his 1884 publication he modestly wrote: “I have therefore published the method, although I am aware that as yet it is very defective and imperfect; but it is hoped that also in the hands of other investigators it will turn out to be useful.”

The technique would go on to become widely used as a method to identify and classify different types of bacteria, and it is still a key component of medical microbiology to this day.

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