Ernst Julius Richard Ewald (14 February 1855 – 22 July 1921) was a German

physiologist Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and ...

born in

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

. He was a younger brother to

gastroenterologist Gastroenterology (from the Greek gastḗr- "belly", -énteron "intestine", and -logía "study of") is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, sometime ...

Carl Anton Ewald (1845–1915). In 1880, after finishing his studies in

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

and medicine, he became an assistant to physiologist

Friedrich Goltz Friedrich Leopold Goltz (14 August 1834 – 5 May 1902) was a German physiologist and nephew of the writer Bogumil Goltz. Biography Born in Posen (Poznań), Grand Duchy of Posen, he studied medicine at the University of Königsberg, and follo ...

(1834-1902) at the

University of Strasbourg The University of Strasbourg (, Unistra) is a public research university located in Strasbourg, France, with over 52,000 students and 3,300 researchers. Founded in the 16th century by Johannes Sturm, it was a center of intellectual life during ...

. In 1900, he succeeded Goltz as chair of physiology at

Strasbourg Strasbourg ( , ; ; ) is the Prefectures in France, prefecture and largest city of the Grand Est Regions of France, region of Geography of France, eastern France, in the historic region of Alsace. It is the prefecture of the Bas-Rhin Departmen ...

, a position he maintained until 1918. Ewald is best remembered for his research of the

vestibular system The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating motor coordination, movement with balance. Together with the cochlea, a part of the auditory sys ...

of the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

, which largely involved experiments performed on the semicircular canal system of

pigeons Columbidae is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in some species feature fleshy ceres. ...

. From these studies the so-called "Ewald laws" are derived, which deal with the effects of

endolymph Endolymph is the fluid contained in the membranous labyrinth of the inner ear. The major cation in endolymph is potassium, with the values of sodium and potassium concentration in the endolymph being 0.91 mM and 154 mM, respectively. ...

motion on body, head and eye movements and also on the phenomena of excitation-inhibition asymmetries in the vestibular system. * Ewald's first law: "The axis of

nystagmus Nystagmus is a condition of involuntary (or voluntary, in some cases) Eye movement (sensory), eye movement. People can be born with it but more commonly acquire it in infancy or later in life. In many cases it may result in visual impairment, re ...

parallels the anatomic axis of the

semicircular canal The semicircular canals are three semicircular interconnected tubes located in the innermost part of each ear, the inner ear. The three canals are the lateral, anterior and posterior semicircular canals. They are the part of the bony labyrinth, ...

that generated it". * Ewald's second law: "Ampullopetal endolymphatic flow produces a stronger response than ampullofugal flow in the horizontal canal". * Ewald's third law: "Ampullofugal flow produces a stronger response than ampullpetal flow in the vertical canals (anterior and posterior semicircular canals). In 1892, he was given an award by the

Paris Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at the forefront of scientific d ...

for his monograph "''Physiologische Untersuchungen über das Endorgan des Nervus octavus''".

Selected writings

* ''Physiologische Untersuchungen über das Endorgan des Nervus octavus'' (1892). * ''Ist die Lunge luftdicht?'' (with Rudolf Kobert). * ''Zur Physiologie des Labyrinths'' (1895) – physiology of the

labyrinth In Greek mythology, the Labyrinth () is an elaborate, confusing structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos. Its function was to hold the Minotaur, the monster eventually killed by the h ...

. * ''Die Physiologie des Kehlkopfs'' (1896) – physiology of the

larynx The larynx (), commonly called the voice box, is an organ (anatomy), organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal ...

. * ''Eine neue Hörtheorie'' (1899) – new theory of hearing. * ''Schallbildertheorie und Erkenntnistheorie'', Z. Sinnesphysiol. 53, 213-217. (1914) – theory of sound patterns and

epistemology Epistemology is the branch of philosophy that examines the nature, origin, and limits of knowledge. Also called "the theory of knowledge", it explores different types of knowledge, such as propositional knowledge about facts, practical knowle ...

References

Deutsche Biographie
(biography) * List of publications copied from an equivalent article at the

German Wikipedia The German Wikipedia () is the German-language edition of Wikipedia, a free and publicly editable online encyclopedia. Founded on 16 March 2001, it is the second-oldest Wikipedia edition (after the English Wikipedia). It has articles, ma ...

. {{DEFAULTSORT:Ewald, Ernst Julius Richard Scientists from Berlin Academic staff of the University of Strasbourg 1855 births 1921 deaths German physiologists 19th-century German scientists