Influential scientist Hans Christian Gram left a durable mark on microbiology thanks to the pioneering staining technique he invented – and he’s now being celebrated with a Google Doodle on the 166th anniversary of his birth.
Born on 13 September, 1853, Gram earned his MD from the University of Copenhagen before working as a resident physician in the city’s municipal hospital.
He then travelled around Europe while expending his expertise bacteriology and pharmacology.
It was while working in the Berlin laboratory of microbiologist Karl Friedländer that Gram developed the “Gram stain”, a scientific method used to identify and characterise bacteria, as noted by the Encyclopaedia Britannica.
The Gram stain method – named after its inventor – consists in treating a smear of bacteria with a violet dye, then rinsing it with iodine solution and an organic solvent.
1/50 12 September 2019
Police officers try to control the crowd after members of the public were invited to view Robert Mugabe’s body as it lies in state at the Rufaro stadium in Harare, Zimbabwe
Reuters
2/50 11 September 2019
A US flag hangs from a steel girder, damaged in the September 11, 2001 attacks on the World Trade Center at a memorial in Jersey City. It is the 18th anniversary of the attacks.
AP
3/50 10 September 2019
Local actors dressed as ancient warriors re-enact a scene from the 7th century battle of Kerbala during a ceremony marking Ashura in Iraq.
Reuters
4/50 9 September 2019
A firefighter assesses the fire spreading across land on Long Gully Road in the town of Drake, Australia. A number of homes have been destroyed by bushfires in New South Wales and Queensland.
EPA
5/50 8 September 2019
Damaged homes after hurricane Dorian devastated Elbow Key Island in Hope Town, Bahamas. The hurricane hit the island chain as a category 5 storm and battered them for two days before moving north.
Getty
6/50 7 September 2019
An artist performs on Tverskaya street during celebrations marking the 872nd anniversary of the city of Moscow.
AFP/Getty
7/50 6 September 2019
Children play football next to a defaced portrait of Former Zimbabwean President Robert Mugabe in Harare on the day he died, aged 95. The former leader was forced to resign in 2017, after a 37-year rule, whose early promise was eroded by economic turmoil, disputed elections and human rights violations, has died.
AP
8/50 5 September 2019
Authorities work at the scene of a train crash in Yokohama, south of Tokyo. According to media reports, more than 30 people were injured after a train hit a track at a crossing.
EPA
9/50 4 September 2019
A police office removes burning tires from the road, as protesters set up fires to block traffic along Airport Road in Abuja, Nigeria.
Reuters
10/50 3 September 2019
A riot police officer throws a teargas canister as looters make off with goods from a store in Germiston, east of Johannesburg, South Africa. Police had earlier fired rubber bullets as they struggled to stop looters who targeted businesses as unrest broke out in several spots in and around the city.
AP
11/50 2 September 2019
A boat off the island of Santa Cruz in California burns in the early hours of Monday morning. More than 30 people were on board the boat, which is thought to have been on a three-day diving trip.
EPA
12/50 1 September 2019
Flowers are laid in a hole in a wall as people gather in the gym of a school, the scene of the hostage crisis, in memory of victims on the fifteenth anniversary of the tragedy in Beslan, North Ossetia region, Russia. More than 330 people, including 186 children, died as a result of the terrorist attack at the school.
AP
13/50 31 August 2019
A man sits in front of riot officers during the rally ‘Calling One Hundred Thousands Christians Praying for Hong Kong Sinners’ in Hong Kong, China.
EPA
14/50 30 August 2019
A migrant forces his way into the Spanish territory of Ceuta. Over 150 migrants made their way into Ceuta after storming a barbed-wire border fence with Morocco.
AFP/Getty
15/50
A beagle jumps through hoops during a show at the Pet Expo Championship 2019 in Bangkok, Thailand. Although the four-day expo is primarily dog oriented it features a wide array of stalls catering to pet owners’ needs as well as showcasing a variety of animals including reptiles, birds, ferrets, and rabbits.
EPA
16/50 28 August 2019
Baby elephants rub their trunks against a tree at the David Sheldrick Wildlife Trust Elephant Orphanage in Nairobi, Kenya. Countries that are part of an international agreement on trade in endangered species agreed on Tuesday to limit the sale of wild elephants, delighting conservationists but dismaying some of the African countries involved.
AP
17/50 27 August 2019
Burning rubbles in the market of Bouake, central Ivory Coast, after a fire broke overnight.
AFP/Getty
18/50 26 August 2019
French President Emmanuel Macron gestures as Canadian Prime Minister Justin Trudeau, second from left, sits between British Prime Minister Boris Johnson, left, and German Chancellor Angela Merkel as they take part in a meeting at the G7 Summit in Biarritz, France.
The Canadian Press via AP
19/50 25 August 2019
A Brazillian Air Force jet drops water to fight a fire in the Amazon rainforest in the state of Rondonia, Brazil.
EPA
20/50 24 August 2019
A police officer prepares to strike a protester as clashes erupt during a pro-democracy march in Hong Kong’s Kowloon Bay.
AFP/Getty
21/50 23 August 2019
Oxfam activists in costumes depicting leaders of the G7 nations protest in Biarritz, France on the day before the summit is due to be held there.
AFP/Getty
22/50 22 August 2019
A vendor sits as she sells models of the Hindu deity Krishna on display at a roadside ahead of the ‘Janmashtami’ festival in Chennai.
Getty
23/50 21 August 2019
A girl reacts next to Pope Francis as he leads the weekly general audience in Paul VI Hall at the Vatican.
Reuters
24/50 20 August 2019
A masked dancer takes part in the Nil Barahi mask dance festival, an annual event during which dancers perform while posing as various deities that people worship to seek blessings, in Bode, Nepal.
Reuters
25/50 19 August 2019
Protesters take to the street to face off with Indonesian police in Manokwari, Papua. The riots broke out, with a local parliament building being torched, as thousands protested allegations that police tear-gassed and arrested students who supported the restive region’s independence.
AFP/Getty
26/50 18 August 2019
People survey the destruction after an overnight suicide bomb explosion that targeted a wedding reception in Kabul, Afghanistan. At least 63 people, mostly wedding guests from the Shi’ite Muslim community, were killed and more than 180 injured when a suicide bomber attacked a wedding hall.
EPA
27/50 17 August 2019
A man retrieves his prize after climbing up a greased pole during a competition held as part of Independence Day celebrations at Ancol Beach in Jakarta. Indonesia is celebrating its 74th anniversary of independence from the Dutch colonial rule.
AP
28/50 16 August 2019
Swiss pianist and composer Alain Roche plays piano suspended in the air at dawn during the 20th “Jeux du Castrum”, a multidisciplinary festival in Switzerland.
AFP/Getty
29/50 15 August 2019
Japan’s Emperor Naruhito and Empress Masako bow during a memorial service ceremony marking the 74th anniversary of Japan’s surrender in World War Two, in Tokyo, Japan.
Reuters
30/50 14 August 2019
A woman walks with a Kashmir’s flag to express solidarity with the people of Kashmir, during a ceremony to celebrate Pakistan’s 72nd Independence Day at the Mausoleum of Muhammad Ali Jinnah in Karachi, Pakistan.
Reuters
31/50 13 August 2019
The extraordinary moment a volcano erupted, shooting luminous hot lava from the surface, as a lightning bolt striked the centre of the mountain. Photographer Martin Reitze, 55, captured rare images of volcanic ash escaping from the Ebeko volcano in Russia whilst the lightning froze the ash cloud in time. Martin, from Munich, was standing around a kilometre away from the northern crater of the volcano when it erupted. The volcano expert said: “The strong lightning which shows in the image is a very rare exception, as it was much stronger than usual.”
Martin Reitze/SWNS
32/50 12 August 2019
People swim in a public bath pool in Zalakaros, Hungary. Some regions of the country have been issued the highest grade of warning by the National Meteorological Service as the temperatures may reach 33-38 centigrade.
EPA
33/50 11 August 2019
A pro-democracy protester is held by police outside Tsim Sha Tsui Police station during a demonstration against the controversial extradition bill in Hong Kong.
AFP/Getty
34/50 10 August 2019
Muslim pilgrims make their way down on a rocky hill known as Mountain of Mercy, on the Plain of Arafat, during the annual hajj pilgrimage, near the holy city of Mecca, Saudi Arabia.
AP
35/50 9 August 2019
Waves hit a sea wall in front of buildings in Taizhou, China’s eastern Zhejiang province. China issued a red alert for incoming Super Typhoon Lekima which is expected to batter eastern Zhejiang province early on August 10 with high winds and torrential rainfall.
AFP/Getty
36/50 8 August 2019
A herder struggles with his flock across a motorway at the city cattle market, ahead of the Eid al-Adha in Abidjan, Ivory Coast. Eid al-Adha is the holiest of the two Muslims holidays celebrated each year, it marks the yearly Muslim pilgrimage (Hajj) to visit Mecca, the holiest place in Islam. Muslims slaughter a sacrificial animal and split the meat into three parts, one for the family, one for friends and relatives, and one for the poor and needy.
EPA
37/50 7 August 2019
Kazakh servicemen perform during a ceremony opening the International Army Games at the 40th military base Otar in Zhambyl Region, Kazakhstan.
Reuters
38/50 6 August 2019
Paleontologist Naturalis Anne Schulp takes part in the construction of the skeleton of the Tyrannosaurus Rex called Trix in Naturalis in Leiden, The Netherlands. After a month-long tour of Europe, Trix is home in time for the opening of the new museum.
AFP/Getty
39/50 5 August 2019
Flowers paying tribute to the eight-year-old boy who died after he was pushed under a train at Frankfurt am Main’s station. The horrific crime happened last week and has led politicians to call for heightened security.
AFP/Getty
40/50 4 August 2019
Mourners take part in a vigil near the border fence between Mexico and the US after a mass shooting at a Walmart store in El Paso killed 20 people. The suspected gunman behind shooting is believed to be a 21-year-old white man called Patrick Crusius.
Reuters
41/50 3 August 2019
Pramac Racing’s rider Jack Miller in action during a practice session at the Motorcycling Grand Prix of the Czech Republic. The race will take place on 4 August.
EPA
42/50 2 August 2019
An extremely rare Pink Meanie jellyfish on display at the Two Oceans Aquarium in Cape Town. The Pink Meanie was discovered during a nightlight jellyfish dive by the collections team in the waters around Robben Island and in Cape Town Harbour. Pink Meanies are jellyvorous, meaning they feed on other jelly species by reeling them in with their long tentacles. Discovering the Pink Meanie in its early ephyra stage meant the team could study its growth rate which turned out to be very quick as it grew to the metaephyra stage in about a week and a half. The Mexican pink meanie (Drymonema larsoni) was only discovered in the year 2000. A Mediterranean relative, known as the Big Pink Jellyfish (Drymonema dalmatinum) has been known to science since the 1800s but when spotted in 2014 it had been almost 70 years since the last sighting. These jellies are incredibly rare and this new South African species is no exception.
EPA
43/50 1 August 2019
Palestinian men breathe fire on the beach as entertainment for children during the summer vacation in Gaza City.
AFP/Getty
44/50 31 July 2019
A woman rows a boat through the lotus plants on the waters of Dal Lake in Srinagar, the summer capital of Indian Kashmir. The lake is a popular tourist destination because of its floating gardens and lotus flowers.
EPA
45/50 30 July 2019
An effigy of demon Ghantakarna is burnt to symbolize the destruction of evil and belief to drive evil spirits and ghost, during the Ghantakarna festival at the ancient city of Bhaktapur, Nepal.
Reuters
46/50 29 July 2019
Hundreds of hot air balloons take part in the Great Line at the Mondial Air Ballons festival, in an attempt to break the 2017 record of 456 balloons aligning in an hour during the biggest meeting in the world, in Chambley, France.
Reuters
47/50 28 July 2019
Anti-extradition bill protesters with umbrellas attend a rally against the police brutality in Hong Kong.
EPA
48/50 27 July 2019
A general view of stalls closed following yesterday’s volcanic eruption at the tourism area of Mount Tangkuban Parahu in the north of Bandung, West Java province, Indonesia.
Reuters
49/50 26 July 2019
Protesters rally against a controversial extradition bill in the arrivals hall at the international airport in Hong Kong.
AFP/Getty
50/50 25 July 2019
The pack rides in a valley during the eighteenth stage of the 106th edition of the Tour de France cycling race between Embrun and Valloire.
AFP/Getty
1/50 12 September 2019
Police officers try to control the crowd after members of the public were invited to view Robert Mugabe’s body as it lies in state at the Rufaro stadium in Harare, Zimbabwe
Reuters
2/50 11 September 2019
A US flag hangs from a steel girder, damaged in the September 11, 2001 attacks on the World Trade Center at a memorial in Jersey City. It is the 18th anniversary of the attacks.
AP
3/50 10 September 2019
Local actors dressed as ancient warriors re-enact a scene from the 7th century battle of Kerbala during a ceremony marking Ashura in Iraq.
Reuters
4/50 9 September 2019
A firefighter assesses the fire spreading across land on Long Gully Road in the town of Drake, Australia. A number of homes have been destroyed by bushfires in New South Wales and Queensland.
EPA
5/50 8 September 2019
Damaged homes after hurricane Dorian devastated Elbow Key Island in Hope Town, Bahamas. The hurricane hit the island chain as a category 5 storm and battered them for two days before moving north.
Getty
6/50 7 September 2019
An artist performs on Tverskaya street during celebrations marking the 872nd anniversary of the city of Moscow.
AFP/Getty
7/50 6 September 2019
Children play football next to a defaced portrait of Former Zimbabwean President Robert Mugabe in Harare on the day he died, aged 95. The former leader was forced to resign in 2017, after a 37-year rule, whose early promise was eroded by economic turmoil, disputed elections and human rights violations, has died.
AP
8/50 5 September 2019
Authorities work at the scene of a train crash in Yokohama, south of Tokyo. According to media reports, more than 30 people were injured after a train hit a track at a crossing.
EPA
9/50 4 September 2019
A police office removes burning tires from the road, as protesters set up fires to block traffic along Airport Road in Abuja, Nigeria.
Reuters
10/50 3 September 2019
A riot police officer throws a teargas canister as looters make off with goods from a store in Germiston, east of Johannesburg, South Africa. Police had earlier fired rubber bullets as they struggled to stop looters who targeted businesses as unrest broke out in several spots in and around the city.
AP
11/50 2 September 2019
A boat off the island of Santa Cruz in California burns in the early hours of Monday morning. More than 30 people were on board the boat, which is thought to have been on a three-day diving trip.
EPA
12/50 1 September 2019
Flowers are laid in a hole in a wall as people gather in the gym of a school, the scene of the hostage crisis, in memory of victims on the fifteenth anniversary of the tragedy in Beslan, North Ossetia region, Russia. More than 330 people, including 186 children, died as a result of the terrorist attack at the school.
AP
13/50 31 August 2019
A man sits in front of riot officers during the rally ‘Calling One Hundred Thousands Christians Praying for Hong Kong Sinners’ in Hong Kong, China.
EPA
14/50 30 August 2019
A migrant forces his way into the Spanish territory of Ceuta. Over 150 migrants made their way into Ceuta after storming a barbed-wire border fence with Morocco.
AFP/Getty
15/50
A beagle jumps through hoops during a show at the Pet Expo Championship 2019 in Bangkok, Thailand. Although the four-day expo is primarily dog oriented it features a wide array of stalls catering to pet owners’ needs as well as showcasing a variety of animals including reptiles, birds, ferrets, and rabbits.
EPA
16/50 28 August 2019
Baby elephants rub their trunks against a tree at the David Sheldrick Wildlife Trust Elephant Orphanage in Nairobi, Kenya. Countries that are part of an international agreement on trade in endangered species agreed on Tuesday to limit the sale of wild elephants, delighting conservationists but dismaying some of the African countries involved.
AP
17/50 27 August 2019
Burning rubbles in the market of Bouake, central Ivory Coast, after a fire broke overnight.
AFP/Getty
18/50 26 August 2019
French President Emmanuel Macron gestures as Canadian Prime Minister Justin Trudeau, second from left, sits between British Prime Minister Boris Johnson, left, and German Chancellor Angela Merkel as they take part in a meeting at the G7 Summit in Biarritz, France.
The Canadian Press via AP
19/50 25 August 2019
A Brazillian Air Force jet drops water to fight a fire in the Amazon rainforest in the state of Rondonia, Brazil.
EPA
20/50 24 August 2019
A police officer prepares to strike a protester as clashes erupt during a pro-democracy march in Hong Kong’s Kowloon Bay.
AFP/Getty
21/50 23 August 2019
Oxfam activists in costumes depicting leaders of the G7 nations protest in Biarritz, France on the day before the summit is due to be held there.
AFP/Getty
22/50 22 August 2019
A vendor sits as she sells models of the Hindu deity Krishna on display at a roadside ahead of the ‘Janmashtami’ festival in Chennai.
Getty
23/50 21 August 2019
A girl reacts next to Pope Francis as he leads the weekly general audience in Paul VI Hall at the Vatican.
Reuters
24/50 20 August 2019
A masked dancer takes part in the Nil Barahi mask dance festival, an annual event during which dancers perform while posing as various deities that people worship to seek blessings, in Bode, Nepal.
Reuters
25/50 19 August 2019
Protesters take to the street to face off with Indonesian police in Manokwari, Papua. The riots broke out, with a local parliament building being torched, as thousands protested allegations that police tear-gassed and arrested students who supported the restive region’s independence.
AFP/Getty
26/50 18 August 2019
People survey the destruction after an overnight suicide bomb explosion that targeted a wedding reception in Kabul, Afghanistan. At least 63 people, mostly wedding guests from the Shi’ite Muslim community, were killed and more than 180 injured when a suicide bomber attacked a wedding hall.
EPA
27/50 17 August 2019
A man retrieves his prize after climbing up a greased pole during a competition held as part of Independence Day celebrations at Ancol Beach in Jakarta. Indonesia is celebrating its 74th anniversary of independence from the Dutch colonial rule.
AP
28/50 16 August 2019
Swiss pianist and composer Alain Roche plays piano suspended in the air at dawn during the 20th “Jeux du Castrum”, a multidisciplinary festival in Switzerland.
AFP/Getty
29/50 15 August 2019
Japan’s Emperor Naruhito and Empress Masako bow during a memorial service ceremony marking the 74th anniversary of Japan’s surrender in World War Two, in Tokyo, Japan.
Reuters
30/50 14 August 2019
A woman walks with a Kashmir’s flag to express solidarity with the people of Kashmir, during a ceremony to celebrate Pakistan’s 72nd Independence Day at the Mausoleum of Muhammad Ali Jinnah in Karachi, Pakistan.
Reuters
31/50 13 August 2019
The extraordinary moment a volcano erupted, shooting luminous hot lava from the surface, as a lightning bolt striked the centre of the mountain. Photographer Martin Reitze, 55, captured rare images of volcanic ash escaping from the Ebeko volcano in Russia whilst the lightning froze the ash cloud in time. Martin, from Munich, was standing around a kilometre away from the northern crater of the volcano when it erupted. The volcano expert said: “The strong lightning which shows in the image is a very rare exception, as it was much stronger than usual.”
Martin Reitze/SWNS
32/50 12 August 2019
People swim in a public bath pool in Zalakaros, Hungary. Some regions of the country have been issued the highest grade of warning by the National Meteorological Service as the temperatures may reach 33-38 centigrade.
EPA
33/50 11 August 2019
A pro-democracy protester is held by police outside Tsim Sha Tsui Police station during a demonstration against the controversial extradition bill in Hong Kong.
AFP/Getty
34/50 10 August 2019
Muslim pilgrims make their way down on a rocky hill known as Mountain of Mercy, on the Plain of Arafat, during the annual hajj pilgrimage, near the holy city of Mecca, Saudi Arabia.
AP
35/50 9 August 2019
Waves hit a sea wall in front of buildings in Taizhou, China’s eastern Zhejiang province. China issued a red alert for incoming Super Typhoon Lekima which is expected to batter eastern Zhejiang province early on August 10 with high winds and torrential rainfall.
AFP/Getty
36/50 8 August 2019
A herder struggles with his flock across a motorway at the city cattle market, ahead of the Eid al-Adha in Abidjan, Ivory Coast. Eid al-Adha is the holiest of the two Muslims holidays celebrated each year, it marks the yearly Muslim pilgrimage (Hajj) to visit Mecca, the holiest place in Islam. Muslims slaughter a sacrificial animal and split the meat into three parts, one for the family, one for friends and relatives, and one for the poor and needy.
EPA
37/50 7 August 2019
Kazakh servicemen perform during a ceremony opening the International Army Games at the 40th military base Otar in Zhambyl Region, Kazakhstan.
Reuters
38/50 6 August 2019
Paleontologist Naturalis Anne Schulp takes part in the construction of the skeleton of the Tyrannosaurus Rex called Trix in Naturalis in Leiden, The Netherlands. After a month-long tour of Europe, Trix is home in time for the opening of the new museum.
AFP/Getty
39/50 5 August 2019
Flowers paying tribute to the eight-year-old boy who died after he was pushed under a train at Frankfurt am Main’s station. The horrific crime happened last week and has led politicians to call for heightened security.
AFP/Getty
40/50 4 August 2019
Mourners take part in a vigil near the border fence between Mexico and the US after a mass shooting at a Walmart store in El Paso killed 20 people. The suspected gunman behind shooting is believed to be a 21-year-old white man called Patrick Crusius.
Reuters
41/50 3 August 2019
Pramac Racing’s rider Jack Miller in action during a practice session at the Motorcycling Grand Prix of the Czech Republic. The race will take place on 4 August.
EPA
42/50 2 August 2019
An extremely rare Pink Meanie jellyfish on display at the Two Oceans Aquarium in Cape Town. The Pink Meanie was discovered during a nightlight jellyfish dive by the collections team in the waters around Robben Island and in Cape Town Harbour. Pink Meanies are jellyvorous, meaning they feed on other jelly species by reeling them in with their long tentacles. Discovering the Pink Meanie in its early ephyra stage meant the team could study its growth rate which turned out to be very quick as it grew to the metaephyra stage in about a week and a half. The Mexican pink meanie (Drymonema larsoni) was only discovered in the year 2000. A Mediterranean relative, known as the Big Pink Jellyfish (Drymonema dalmatinum) has been known to science since the 1800s but when spotted in 2014 it had been almost 70 years since the last sighting. These jellies are incredibly rare and this new South African species is no exception.
EPA
43/50 1 August 2019
Palestinian men breathe fire on the beach as entertainment for children during the summer vacation in Gaza City.
AFP/Getty
44/50 31 July 2019
A woman rows a boat through the lotus plants on the waters of Dal Lake in Srinagar, the summer capital of Indian Kashmir. The lake is a popular tourist destination because of its floating gardens and lotus flowers.
EPA
45/50 30 July 2019
An effigy of demon Ghantakarna is burnt to symbolize the destruction of evil and belief to drive evil spirits and ghost, during the Ghantakarna festival at the ancient city of Bhaktapur, Nepal.
Reuters
46/50 29 July 2019
Hundreds of hot air balloons take part in the Great Line at the Mondial Air Ballons festival, in an attempt to break the 2017 record of 456 balloons aligning in an hour during the biggest meeting in the world, in Chambley, France.
Reuters
47/50 28 July 2019
Anti-extradition bill protesters with umbrellas attend a rally against the police brutality in Hong Kong.
EPA
48/50 27 July 2019
A general view of stalls closed following yesterday’s volcanic eruption at the tourism area of Mount Tangkuban Parahu in the north of Bandung, West Java province, Indonesia.
Reuters
49/50 26 July 2019
Protesters rally against a controversial extradition bill in the arrivals hall at the international airport in Hong Kong.
AFP/Getty
50/50 25 July 2019
The pack rides in a valley during the eighteenth stage of the 106th edition of the Tour de France cycling race between Embrun and Valloire.
AFP/Getty
Bacteria with a thick cell wall remain purple and are called Gram-positive.
Bacteria with a thinner cell wall, on the other hand, do not retain the stain and are called Gram-negative.
Gram retired in 1923 and died in 1938 at 85 years old.
The Gram method remains widely used eight decades after his death, cementing his legacy in the world of microbiology.
