Christian Andreas Victor Hensen (10 February 1835 – 5 April 1924) was a German

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

and marine biologist ( planktology). He coined the term ''

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

'' and laid the foundation for

biological oceanography Biological oceanography is the study of how organisms affect and are affected by the physics, chemistry, and geology of the oceanographic system. Biological oceanography may also be referred to as ocean ecology, in which the root word of ecology ...

and quantitative studies.

Family

Hensen was born in the town of

Schleswig The Duchy of Schleswig (; ; ; ; ; ) was a duchy in Southern Jutland () covering the area between about 60 km (35 miles) north and 70 km (45 mi) south of the current border between Germany and Denmark. The territory has been di ...

where his father ran a school for the deaf and dumb. His mother Henriette Caroline Amalie was the daughter of physician Carl Ferdinand Suadicani who founded an asylum in Schleswig. Hensen had eight sisters and five brothers including from his father's first marriage.

Education and work

Hensen went to school in Schleswig from 1845 to 1859 and then joined a grammar school in Glückstadt (Holstein) after which he joined to study medicine at the universities of

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 ...

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 ...

(studying under

Müller Müller may refer to: Companies * Müller (company), a German multinational dairy company ** Müller Milk & Ingredients, a UK subsidiary of the German company * Müller (store), a German retail chain * GMD Müller, a Swiss aerial lift manufacturi ...

) and

Kiel Kiel ( ; ) is the capital and most populous city in the northern Germany, German state of Schleswig-Holstein. With a population of around 250,000, it is Germany's largest city on the Baltic Sea. It is located on the Kieler Förde inlet of the Ba ...

. In 1859, he received his doctorate in Kiel for a thesis on

epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...

and urinary secretions. He worked for a while at Kiel and in 1859 he became a lecturer in anatomy and histology. He became an associate professor in 1864, succeeding Peter Ludwig Panum. In 1867, he became a member of the

Prussian House of Representatives The Prussian House of Representatives () was the lower chamber of the Landtag of Prussia (), the parliament of Kingdom of Prussia, Prussia from 1850 to 1918. Together with the upper house, the Prussian House of Lords, House of Lords (), it formed ...

to push towards studies of the ocean. Upon his initiative, the ''Royal

Prussia Prussia (; ; Old Prussian: ''Prūsija'') was a Germans, German state centred on the North European Plain that originated from the 1525 secularization of the Prussia (region), Prussian part of the State of the Teutonic Order. For centuries, ...

n Commission for the Exploration of the Oceans'' was founded. Hensen's students included Paul Höber, Hans Winterstein, and Hans Piper. He became a professor of

physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

in 1868 and worked at Kiel until 1891. During his time, he was head of five marine biological expeditions to the

Baltic Baltic may refer to: Peoples and languages *Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originatin ...

and

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

s, as well as the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

. He led an expedition in 1889 on the steamboat ''National'' from Kiel to southern

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

in the north to as far as near the mouth of the

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

Pará Pará () is a Federative units of Brazil, state of Brazil, located in northern Brazil and traversed by the lower Amazon River. It borders the Brazilian states of Amapá, Maranhão, Tocantins (state), Tocantins, Mato Grosso, Amazonas (Brazilian st ...

, Brazil in the south to study whether plankton can be found more in tropical waters than cold waters. Hensen also worked in

embryology Embryology (from Ancient Greek, Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logy, -logia'') is the branch of animal biology that studies the Prenatal development (biology), prenatal development of gametes (sex ...

and

anatomy 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 ...

examining the eye of cephalopods and the hearing organs of decapods. He discovered a structure in the

ear In vertebrates, an ear is the organ that enables hearing and (in mammals) body balance using the vestibular system. In humans, the ear is described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear co ...

, the Hensen duct, also known as the Canal of Hensen. He also discovered Hensen's cells, Hensen's stripe, and two structures essential for the development of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s, the Hensen's node and Hensen's line. Hensen was for several years dean of the Faculty of Medicine and several times was rector of the University of Kiel. He was honorary doctor of Kiel, a member of the Leopoldine Academy, and a corresponding member of the Bavarian and Prussian academies of science.

Family and legacy

Hensen married Andrea Katharina Friederike Seestern-Pauly in 1870 and they had two sons and daughters. The ''RV VICTOR HENSEN'' is a research vessel named in his honor.

Works

* ''Zur Morphologie der Schnecke des Menschen und der Säugethiere'' (1863)

References

External links

Some text by Hensen
(in German and English)

(in German)
Correspondence between Darwin and Hensen
1835 births 1924 deaths People from Schleswig, Schleswig-Holstein Members of the Prussian House of Representatives People from the Duchy of Schleswig University of Würzburg alumni Humboldt University of Berlin alumni University of Kiel alumni Academic staff of the University of Kiel {{Germany-zoologist-stub