Hans Christian Joachim Gram (13 September 1853 – 14 November 1938) was a

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

bacteriologist A bacteriologist is a microbiologist, or similarly trained professional, in bacteriology -- a subdivision of microbiology that studies bacteria, typically pathogenic ones. Bacteriologists are interested in studying and learning about bacteria, ...

noted for his development of the

Gram stain In microbiology and bacteriology, Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish b ...

, still a standard technique to classify bacteria and make them more visible under a microscope.

Early life and education

Gram was the son of Frederik Terkel Julius Gram, a professor of

jurisprudence Jurisprudence, or legal theory, is the theoretical study of the propriety of law. Scholars of jurisprudence seek to explain the nature of law in its most general form and they also seek to achieve a deeper understanding of legal reasoning a ...

, and Louise Christiane Roulund. He studied at the

University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public research university in Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia after Uppsala Unive ...

, and was an assistant for

botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

to the zoologist

Japetus Steenstrup Johannes Japetus Smith Steenstrup FRS(For) H FRSE (8 March 1813 – 20 June 1897) was a Danish zoologist, biologist, and professor. Life Born in Vang, Thy on 8 March 1813, he held a lectorate in mineralogy in Sorø until 1845 when he became ...

. His study of plants introduced him to the basics of pharmacology and the use of the

microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisi ...

. Gram began medical school in 1878 and graduated in 1883. He travelled throughout Europe between 1878 and 1885.

Career

Gram stain

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, in 1884, Gram developed a method for distinguishing between two major classes of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

.
An English translation is in
A translation is also at This technique, known as

Gram staining In microbiology and bacteriology, Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish bac ...

, continues to be a standard procedure of medical microbiology. This work gained Gram an international reputation. The staining method later played a major role in classifying

. Gram was a modest man, and in his initial publication he remarked, "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." A Gram stain is made using a primary stain of crystal violet and a counterstain of safranin. Bacteria that turn purple when stained are termed 'Gram-positive', while those that turn red when counterstained are termed 'Gram-negative'.

Other work

Gram's initial work concerned the study of human

red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s. He was among the first to recognise that macrocytes were characteristic of

pernicious anaemia Pernicious anemia is a type of vitamin B12 deficiency anemia, a disease in which not enough red blood cells are produced due to the malabsorption of vitamin B12. Malabsorption in pernicious anemia results from the lack or loss of intrinsic ...

. During 1891, Gram taught pharmacology, and later that year was appointed professor at the

. In 1900, he resigned his professorship of pharmacology to become professor of medicine. As a professor, he published four volumes of clinical lectures which became used widely in

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establish ...

. He retired from the University of Copenhagen in 1923, and died in 1938.

Popular recognition

On 13 September 2019,

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commemorated the anniversary of his birth with a

Doodle A doodle is a drawing made while a person's attention is otherwise occupied. Doodles are simple drawings that can have concrete representational meaning or may just be composed of random and abstract lines or shapes, generally without ever lift ...

for Canada, Peru, Argentina, Australia, New Zealand, Israel, India and some European countries.

Personal life

Gram's great-granddaughter Lone Gram is a microbiologist who works at the Technical University of Denmark.

References

External links

* * {{DEFAULTSORT:Gram, Hans Christian 1853 births 1938 deaths Danish bacteriologists Danish microbiologists