Carl Georg Lucas Christian Bergmann (18 May 1814 – 30 April 1865), also known as Karl Georg Lucas Christian Bergmann, was a German

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 ...

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 ...

, and biologist. He developed

Bergmann's rule Bergmann's rule is an ecogeographical rule that states that, within a broadly distributed taxonomic clade, populations and species of larger size are found in colder environments, while populations and species of smaller size are found in warmer ...

(that populations and species of animals of larger size are found in colder environments). He

microscopically Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical, e ...

examined the cells of the

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

to determine which of them convert light into neural signals that lead ultimately to

visual perception Visual perception is the ability to detect light and use it to form an image of the surrounding Biophysical environment, environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual percept ...

: the

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

and the rods. Bergmann also coined the terms

fovea centralis The ''fovea centralis'' is a small, central pit composed of closely packed Cone cell, cones in the eye. It is located in the center of the ''macula lutea'' of the retina. The ''fovea'' is responsible for sharp central visual perception, vision ...

(for the very center of the retina), homoiothermic (referring to warm-blooded animals), and

poikilothermic A poikilotherm () is an animal (Greek ''poikilos'' – 'various', 'spotted', and ''therme'' – 'heat') whose internal temperature varies considerably. Poikilotherms have to survive and adapt to environmental stress. One of the most important s ...

(referring to non-homoiothermic animals).

Biography

Bergmann was born in

Göttingen Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...

, then in the

Electorate of Hanover The Electorate of Hanover ( or simply ''Kurhannover'') was an Prince-elector, electorate of the Holy Roman Empire located in northwestern Germany that arose from the Principality of Calenberg. Although formally known as the Electorate of Brun ...

. His father was Friedrich Christian Bergmann (1785–1845), a lawyer and professor. His mother was Henriette Christine, née Mejer. After graduating from high school in Holzminden in 1832, he studied medicine and natural sciences at the universities in Göttingen and

Würzburg Würzburg (; Main-Franconian: ) is, after Nuremberg and Fürth, the Franconia#Towns and cities, third-largest city in Franconia located in the north of Bavaria. Würzburg is the administrative seat of the Regierungsbezirk Lower Franconia. It sp ...

. In 1838, Bergmann received his medical doctorate at the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen (, commonly referred to as Georgia Augusta), is a Public university, public research university in the city of Göttingen, Lower Saxony, Germany. Founded in 1734 ...

, with a dissertation entitled "De placentae foetalis resorptione" (On the resorption of the fetal placenta). In 1839, Bergmann obtained his

habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in Germany, France, Italy, Poland and some other European and non-English-speaking countries. The candidate fulfills a university's set criteria of excelle ...

at the University of Göttingen. He worked as a private lecturer at the university in medicine for physiology, comparative anatomy, and forensic medicine. From 1840 Bergmann was assistant to

Rudolf Wagner Rudolf Friedrich Johann Heinrich Wagner (30 July 1805 – 13 May 1864) was a German anatomist and physiologist and the co-discoverer of the germinal vesicle. He made important investigations on ganglia, nerve-endings, and the sympathetic nerve ...

for the university's comparative anatomical collection. In 1843 he was appointed associate professor at Göttingen University. In 1847 Bergmann published the work on the relationships between the heat economy of animals and their size. This regular connection between heat balance and body size in animals was named after him - Bergmann's rule.Karl Georg Lucas Christian Bergmann
at Who Named It From October 1852 Bergmann became a full professor of anatomy and physiology at the

University of Rostock The University of Rostock () is a public university located in Rostock, Mecklenburg-Vorpommern, Germany. Founded in 1419, it is the third-oldest university in Germany. It is the oldest university in continental northern Europe and the Baltic Se ...

and a member of

Rostock Rostock (; Polabian language, Polabian: ''Roztoc''), officially the Hanseatic and University City of Rostock (), is the largest city in the German States of Germany, state of Mecklenburg-Vorpommern and lies in the Mecklenburgian part of the sta ...

's Medicinal Commission. In 1861 he was appointed ''Obermedicinalrath'' (Senior Medical Officer). From 1858–1859, Bergmann was rector of Rostock University. In 1859, Bergmann was elected as a member of the Göttingen Academy of Sciences. In 1864, he was elected as a member of the Leopoldina Academy of Scholars. Carl Bergmann was married to Wilhelmine Bergmann, née Heusinger von Waldegge. Bergmann died in

Geneva Geneva ( , ; ) ; ; . is the List of cities in Switzerland, second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the ca ...

on 30 April 1865, following his return from

Menton Menton (; in classical norm or in Mistralian norm, , ; ; or depending on the orthography) is a Commune in France, commune in the Alpes-Maritimes department in the Provence-Alpes-Côte d'Azur region on the French Riviera, close to the Italia ...

, where he had resided for the winter because of his deteriorating health.

Research

Neuroscience

Prior to the 1850s, most scientists believed that vision begins in the

retinal ganglion cell A retinal ganglion cell (RGC) is a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the eye. It receives visual information from photoreceptor cell, photoreceptors via two intermediate neuron types: Bipolar ...

s. However in 1854, Bergmann argued that rods and cones must be the retinal cells responsible for converting light into vision. This was because he found that these were the only cells of the fovea centralis, all the others having been pulled out of the path of light to the retina. Bergmann said:

The fovea centralis, located in the middle of the most acute part of the retina, is, of course, not a blind spot. Rather, as an unusually constructed part located here, it can be assumed to be particularly advantageous. In fact, it is only those retinal elements present here that can be assumed to be percipient.

Later in the same year Heinrich Müller arrived at the same conclusion from careful measurement of moving shadows of the retinal blood vessels, using the principal of

motion parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

Publications

* Bergmann, C. (1846)
''Lehrbuch der Medicina Forensis für Juristen''
Friedrich Vieweg und Sohn, Braunschweig * Bergmann, C. (1848)
''Über die Verhältnisse der Wärmeökonomie der Thiere zu ihrer Grösse''
. Vandenhoeck und Ruprecht, Göttingen. * Bergmann, C. and R. Leuckart (1855)
''Anatomisch-physiologische Uebersicht des Thierreichs. Vergleichende Anatomie und Physiologie''
J. B. Müller, Stuttgart. * Bergmann, C. (1854). "Zur Kenntnis des gelben Flecks der Netzhaut." Zeitschrift fur rationelle Medicin 3(1): 245-252. * Bergmann, C. (1857). "Anatomisches und Physiologisches über die Netzhaut des Auges." Zeitschrift fur rationelle Medicin 3(1): 83-108.

References

{{DEFAULTSORT:Bergmann, Carl 1814 births 1865 deaths German anatomists 19th-century German biologists German physiologists Academic staff of the University of Rostock University of Göttingen alumni Scientists from Göttingen Members of the Göttingen Academy of Sciences and Humanities