Louis-Charles Malassez (21 September 1842 – 22 December 1909) was a French

anatomist Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

and histologist born in

Nevers Nevers ( , ; , later ''Nevirnum'' and ''Nebirnum'') is a city and the Prefectures in France, prefecture of the Nièvre Departments of France, department in the Bourgogne-Franche-Comté Regions of France, region in central France. It was the pr ...

, department of

Nièvre Nièvre () is a department in the Bourgogne-Franche-Comté region, central-east France. Named after the river Nièvre, it had a population of 204,452 in 2019.Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

, where he worked as an ''interne'' from 1867. He served with the 5th Ambulance Corps during the

Franco-Prussian War The Franco-Prussian War or Franco-German War, often referred to in France as the War of 1870, was a conflict between the Second French Empire and the North German Confederation led by the Kingdom of Prussia. Lasting from 19 July 1870 to 28 Janua ...

, afterwards returning to Paris, where he worked with distinguished physicians that included

Claude Bernard Claude Bernard (; 12 July 1813 – 10 February 1878) was a French physiologist. I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science". He originated the term ''milieu intérieur'' and the associated c ...

Jean-Martin Charcot Jean-Martin Charcot (; 29 November 1825 – 16 August 1893) was a French neurology, neurologist and professor of anatomical pathology. He worked on groundbreaking work about hypnosis and hysteria, in particular with his hysteria patient Louise A ...

and Pierre Potain. In 1875, he attained the chair of anatomy at

Collège de France The (), formerly known as the or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment () in France. It is located in Paris near La Sorbonne. The has been considered to be France's most ...

, and in 1894 he became a member of the ''

Académie de Médecine An academy (Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of tertiary education. The name traces back to Plato's school of philosophy, founded approximately 386 BC at Akademia, a sanctuary of Athena, the go ...

''. He conducted histological research of the blood, and is credited for design of the

hemocytometer The hemocytometer (or haemocytometer, or Burker's chamber) is a counting-chamber device originally designed and usually used for counting blood cells. The hemocytometer was invented by Louis-Charles Malassez and consists of a thick glass mi ...

, a device used to quantitatively measure blood cells. In the field of

dentistry Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the Human tooth, teeth, gums, and Human mouth, mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, dis ...

, he described residual cells of the epithelial root sheath in the

periodontal ligament The periodontal ligament, commonly abbreviated as the PDL, are a group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which they sit. It inserts into root cementum on one side and onto alveo ...

. These remaining cells are referred to as epithelial cell rests of Malassez (ERM). A

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

called '' Malassezia'' bears his name. The species in the genus include: '' Malassezia furfur'', '' Malassezia ovalis'', '' Malassezia pachydermatis'', '' Malassezia sympodialis'' and ''Malassezia orbiculare''. ''Malassezia furfur'' is a

lipophilic Lipophilicity (from Greek language, Greek λίπος "fat" and :wikt:φίλος, φίλος "friendly") is the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such compounds are c ...

species that forms on human skin and can cause seborrheic

dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

and

tinea versicolor Tinea versicolor (also pityriasis versicolor) is a condition characterized by a skin eruption on the trunk and proximal extremities. The majority of tinea versicolor is caused by the fungus '' Malassezia globosa'', although '' Malassezia furfur' ...

, ''Malassezia pachydermatis'' is a species that is associated with

otitis externa Otitis externa, also called swimmer's ear, is inflammation of the ear canal. It often presents with ear pain, swelling of the ear canal, and occasionally decreased hearing. Typically there is pain with movement of the outer ear. A high fever ...

in dogs.

Selected publications

* 'De la numération des globules rouges du sang. I. Des méthodes de numération. II. De la richesse du sang en globules rouges dans les différentes parties de l'arbre circulatoire. Paris 1873 * Sur les lésions histologiques de la syphilis testiculaire. Paris, 1881 - (with Paul Reclus 1847-1914). * Sur l’existence d’amas épithéliaux autour de la racine des dents chez l’homme adulte et a l’état normal (débris épithéliaux paradentaires. Paris, 1885 * Sur les role des débris épithéliaux paradentaires. In: Archives de physiologie normale et pathologique. Paris, S. 309–340, 1885

References

Dorlands's Medical Dictionary, Definition of Malassezia species & Cell rests
*

Malassezia Infections of the Skin, D. R. Thomas, MD, FRCPC * "List of publications copied from the equivalent article at the

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.'' French histologists French anatomists Academic staff of the Collège de France 1842 births 1909 deaths People from Nevers Burials at Père Lachaise Cemetery {{France-scientist-stub