Georges Hayem was a physician and hematologist who was a native of Paris

Paris

Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

. He studied medicine in Paris, and later became a professor of therapy

Therapy

This is a list of types of therapy .* Adventure therapy* Animal-assisted therapy* Aquatic therapy* Aromatherapy* Art and dementia* Art therapy* Authentic Movement* Behavioral therapy* Bibliotherapy* Buteyko Method* Chemotherapy...

 and materia medica

Materia medica

Materia medica is a Latin medical term for the body of collected knowledge about the therapeutic properties of any substance used for healing . The term 'materia medica' derived from the title of a work by the Ancient Greek physician Pedanius Dioscorides in the 1st century AD, De materia medica libre...

. From 1878 until 1911 he practiced medicine at the Hôpital Tenon, and afterwards was associated with the Hôpital St. Antoine.

Georges Hayem was a pioneer in the field of hematology

Hematology

Hematology, also spelled haematology , is the branch of biology physiology, internal medicine, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases...

, and is remembered for his work involving the formation of leukocytes and erythrocytes. In 1889 he performed the first accurate count of blood platelet

Platelet

Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s, and is credited with developing a solution of mercury bichloride, sodium chloride

Sodium chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

 and sodium sulfate

Sodium sulfate

Sodium sulfate is the sodium salt of sulfuric acid. When anhydrous, it is a white crystalline solid of formula Na2SO4 known as the mineral thenardite; the decahydrate Na2SO4·10H2O has been known as Glauber's salt or, historically, sal mirabilis since the 17th century. Another solid is the...

 for dilution of blood prior to counting erythrocytes with a hemocytometer

Hemocytometer

The hemocytometer or haemocytometer is a device originally designed for the counting of blood cells. It is now also used to count other types of cells as well as other microscopic particles....

. In 1874 he provided an early description of chronic interstitial hepatitis

Hepatitis

Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

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With bacteriologist Georges-Fernand Widal

Georges-Fernand Widal

Georges-Fernand-Isidor Widal; was a French physician.From 1886 to 1888 he devoted himself to public demonstrations of the researches of the faculty of pathological anatomy, and during the 2 years following was in charge of a course in bacteriology in the laboratory of Professor Victor André Cornil...

 (1862-1929), the eponymous "Hayem-Widal syndrome" is named, which is a historical term for acquired hemolytic anemia

Hemolytic anemia

Hemolytic anemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells , either in the blood vessels or elsewhere in the human body . It has numerous possible causes, ranging from relatively harmless to life-threatening...

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