Julius Bernstein (18 December 1839 – 6 February 1917) was a German physiologist born in

Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...

. His father was Aron Bernstein (1812—1884), a founder of the Reform Judaism Congregation in Berlin 1845; his son was the mathematician Felix Bernstein (1878—1956).

Academic career

He studied medicine at the

University of Breslau A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. Universities typically offer both undergraduate and postgraduate programs. In the United States, th ...

under

Rudolf Heidenhain Rudolf Peter Heinrich Heidenhain (; 29 January 1834 – 13 October 1897) was a German physiologist born in Marienwerder, East Prussia (now Kwidzyn, Poland). His son, Martin Heidenhain, was a highly regarded anatomist. Academic career He studi ...

(1834-1897), and at the

University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative ...

with

Emil Du Bois-Reymond Emil Heinrich du Bois-Reymond (7 November 181826 December 1896) was a German physician and physiologist, the co-discoverer of nerve action potential, and the developer of experimental electrophysiology. Life Du Bois-Reymond was born in Berlin a ...

(1818-1896). He received his medical degree at Berlin in 1862, and two years later began work in the physiological institute at the

University of Heidelberg } Heidelberg University, officially the Ruprecht Karl University of Heidelberg, (german: Ruprecht-Karls-Universität Heidelberg; la, Universitas Ruperto Carola Heidelbergensis) is a public research university in Heidelberg, Baden-Württemberg, ...

as an assistant to

Hermann von Helmholtz Hermann Ludwig Ferdinand von Helmholtz (31 August 1821 – 8 September 1894) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The Helmholtz Associatio ...

(1821-1894). In 1872 he succeeded

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

(1834-1902) as professor of physiology at the

University of Halle Martin Luther University of Halle-Wittenberg (german: Martin-Luther-Universität Halle-Wittenberg), also referred to as MLU, is a public, research-oriented university in the cities of Halle and Wittenberg and the largest and oldest university in ...

, where in 1881 he founded an institute of physiology.Short biography, bibliography, and links on digitized sources
in the

Virtual Laboratory The online project Virtual Laboratory. Essays and Resources on the Experimentalization of Life, 1830-1930, located at the Max Planck Institute for the History of Science, is dedicated to research in the history of the experimentalization of life. T ...

of the

Max Planck Institute for the History of Science The Max Planck Institute for the History of Science (German: Max-Planck-Institut für Wissenschaftsgeschichte) is a scientific research institute founded in March 1994. It is dedicated to addressing fundamental questions of the history of knowledg ...

Contributions

Bernstein's work was concentrated in the fields of

neurobiology Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developme ...

and

biophysics Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. ...

. He is largely recognized for his "membrane hypothesis" in regards to the origin of the "

resting potential A relatively static membrane potential which is usually referred to as the ground value for trans-membrane voltage. The relatively static membrane potential of quiescent cells is called the resting membrane potential (or resting voltage), as opp ...

" and the "action potential" in the nerve.Geocities.com
Short biography Bernstein (1902, 1912) correctly proposed that excitable cells are surrounded by a membrane selectively permeable to K⁺

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s at rest and that during excitation the membrane permeability to other ions increases. His "membrane hypothesis" explained the resting potential of nerve and muscle as a diffusion potential set up by the tendency of positively charged ions to diffuse from their high concentration in

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

to their low concentration in the extracellular solution while other ions are held back. During excitation, the internal negativity would be lost transiently as other ions are allowed to diffuse across the membrane, effectively short-circuiting the K⁺ diffusion potential. In the English-language literature, the words "membrane breakdown" were used to describe Bernstein's view of excitation. (From ''Ion Channels of Excitable Membranes'', Third Edition, by Bertil Hille). Bernstein's pioneering research laid the groundwork for experimentation on the conduction of the

nerve impulse An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, ...

, and eventually the transmission of information in the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

. He is credited with invention of a "differential rheotome", a device used to measure the

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity i ...

of bio-electric impulses.Seyfarth E-A. (2006), "Julius Bernstein (1839–1917): pioneer neurobiologist and biophysicist"
, Biological Cybernetics 94: 2–8 Biol Cybern (2006) 94: 2–8 The German Bernstein Network Computational Neuroscience has been named after him.Why 'Bernstein'?
at the NNCN web site

Written works

*
Untersuchungen über den Erregungsvorgang im Nerven- und Muskelsysteme
', Heidelberg: Winter, 1871 - Experiments on the excitation process in nerve and

muscle system The muscular system is an organ system consisting of skeletal, smooth, and cardiac muscle. It permits movement of the body, maintains posture, and circulates blood throughout the body. The muscular systems in vertebrates are controlled through t ...

s. * ''Die fünf Sinne des Menschen'', Leipzig: Brockhaus, 1875 - The five senses of humans. * ''Die mechanische Theorie des Lebens, ihre Grundlagen und ihre Erfolge''.

Braunschweig Braunschweig () or Brunswick ( , from Low German ''Brunswiek'' , Braunschweig dialect: ''Bronswiek'') is a city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the ...

: Vieweg, 1890 - The mechanical theory of life, etc. * ''Lehrbuch der Physiologie des thierischen Organismus, im speciellen des Menschen''. Stuttgart: F. Enke, 1894 - Textbook of physiology on the "animal organism", etc.
''Elektrobiologie: Die Lehre von den elektrischen Vorgängen im Organismus auf moderner Grundlage dargestellt''
Braunschweig: Vieweg, 1912 - Book on electrobiology (Treatise that provided the first quantitative theory of nerve and muscle action based on solid experimentation, precise measurements and the use of biophysical models).

References

Early Hypotheses to Explain the Action Potential: Bernstein's hypothesis

Julius Bernstein (1839–1917): pioneer neurobiologist and biophysicist
(The above listed #1 links to his son Felix Bernstein)

External links

* * {{DEFAULTSORT:Bernstein, Julius 1839 births 1917 deaths Scientists from Berlin People from the Province of Brandenburg 19th-century German Jews German physiologists German neuroscientists University of Breslau alumni Humboldt University of Berlin alumni Heidelberg University faculty Martin Luther University of Halle-Wittenberg faculty

Academic career

Contributions

Written works

See also

References

Further reading

External links