Jacques Loeb
Jacques Loeb was a German
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

-born American physiologist and biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...



Loeb was educated at the universities of Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, Munich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...

, and Strasburg
Strasbourg is the capital and principal city of the Alsace region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace are historically German-speaking,...

 (M.D. 1884). He took postgraduate courses at the universities of Strasburg and Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, and in 1886 became assistant at the physiological institute of the University of Würzburg
University of Würzburg
The University of Würzburg is a university in Würzburg, Germany, founded in 1402. The university is a member of the distinguished Coimbra Group.-Name:...

, remaining there till 1888. In a similar capacity, he then went to Strasburg University. During his vacations he pursued biological researches, at Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...

 in 1888, and at Naples
Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...

 in 1889 and 1890.

In 1892 he was called to the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...

 as assistant professor of physiology and experimental biology, becoming associate professor in 1895, and professor of physiology in 1899. John B. Watson
John B. Watson
John Broadus Watson was an American psychologist who established the psychological school of behaviorism. Watson promoted a change in psychology through his address Psychology as the Behaviorist Views it which was given at Columbia University in 1913...

 "father of Behaviorism" was a student of Loebs neurology classes at University of Chicago. In 1902 he was called to fill a similar chair at the University of California
University of California
The University of California is a public university system in the U.S. state of California. Under the California Master Plan for Higher Education, the University of California is a part of the state's three-tier public higher education system, which also includes the California State University...


In 1910 Loeb moved to the Rockefeller Institute for Medical Research in New York, where he headed a department created for him. He remained at Rockefeller (now Rockefeller University
Rockefeller University
The Rockefeller University is a private university offering postgraduate and postdoctoral education. It has a strong concentration in the biological sciences. It is also known for producing numerous Nobel laureates...

) until his death. Throughout most of these years Loeb spent his summers at the Marine Biological Laboratory
Marine Biological Laboratory
The Marine Biological Laboratory is an international center for research and education in biology, biomedicine and ecology. Founded in 1888, the MBL is the oldest independent marine laboratory in the Americas, taking advantage of a coastal setting in the Cape Cod village of Woods Hole, Massachusetts...

 in Woods Hole
Woods Hole, Massachusetts
Woods Hole is a census-designated place in the town of Falmouth in Barnstable County, Massachusetts, United States. It lies at the extreme southwest corner of Cape Cod, near Martha's Vineyard and the Elizabeth Islands...

, Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...

, performing experiments on various marine invertebrates. It was there that Jacques Loeb performed his most famous experiment, on artificial parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...

. Loeb was able to cause the eggs of sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s to begin embryonic development without sperm. This was achieved by slight chemical modifications of the water in which the eggs were kept, which served as the stimulus for the development to begin.

Loeb became one of the most famous scientists in America, widely covered in newspapers and magazines. He was the model for the character of Max Gottlieb in Sinclair Lewis
Sinclair Lewis
Harry Sinclair Lewis was an American novelist, short-story writer, and playwright. In 1930, he became the first writer from the United States to be awarded the Nobel Prize in Literature, "for his vigorous and graphic art of description and his ability to create, with wit and humor, new types of...

's Pulitzer
Pulitzer Prize
The Pulitzer Prize is a U.S. award for achievements in newspaper and online journalism, literature and musical composition. It was established by American publisher Joseph Pulitzer and is administered by Columbia University in New York City...

-winning novel Arrowsmith
Arrowsmith (novel)
Arrowsmith is a novel by American author and playwright Sinclair Lewis that was published in 1925. It won the 1926 Pulitzer Prize for Lewis but he refused to accept it. Lewis was greatly assisted in its preparation by science writer Dr. Paul de Kruif, who received 25% of the royalties on sales, but...

, the first great work of fiction to idealize and idolize pure science. Mark Twain
Mark Twain
Samuel Langhorne Clemens , better known by his pen name Mark Twain, was an American author and humorist...

 also wrote an essay titled "Dr. Loeb's Incredible Discovery", which urges the reader not to support a rigid general consensus, but instead be open to new scientific advances.

Loeb was nominated many times for the Nobel Prize but never won.

Research area

The main subjects of Loeb's work were:
  • Animal tropism
    A tropism is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. In tropisms, this response is dependent on the direction of the stimulus...

    s and their relation to the instincts of animals
  • Heteromorphosis, the replacement of an injured or removed organ by a different organ
  • Toxic and antitoxic effects of ions
  • Artificial parthenogenesis
  • Hybridization of the eggs of sea-urchins by the sperm of starfish


Among Loeb's works the following may be mentioned:
  • Der Heliotropismus der Thiere und seine Uebereinstimmung mit dem Heliotropismus der Pflanzen, Würzburg: Verlag von Georg Hertz, 1890.
  • Untersuchungen zur physiologischen Morphologie der Thiere, Würzburg: Verlag von Georg Hertz, 1891–1892. 2 vols., vol. 1: Ueber Heteromorphose, vol. 2: Organbildung und Wachsthum.
  • Einleitung in die vergleichende Gehirnphysiologie und vergleichende Psychologie, Leipzig: J. A. Barth, 1899. English ed., Comparative physiology of the brain and comparative psychology, New York: Putnam, 1900.
  • Studies in general physiology, Chicago: The University of Chicago Press, 1905.
  • The dynamics of living matter, New York: Columbia University Press, 1906.
  • The mechanistic conception of life: biological essays, Chicago: The University of Chicago Press, 1912; reprint, Cambridge, Mass.: Harvard University Press, 1964.
  • Artificial parthenogenesis and fertilization, tr. from German by W. O. Redman King, rev. and ed. by Loeb. Chicago: The University of Chicago Press, 1913.
  • The organism as a whole, from a physicochemical viewpoint, New York: Putnam, 1916.
  • Forced movements, tropisms, and animal conduct, Philadelphia: J. B. Lippincott Company
    J. B. Lippincott Company
    J. B. Lippincott & Co. was an American publishing house founded in Philadelphia, Pennsylvania in 1836 by Joshua Ballinger Lippincott.Formed by descendants of the Religious Society of Friends, Joshua Lippincott's company began selling a line of Bibles, prayer books and other religious works before...

    , 1918.
  • Proteins and the theory of colloidal behavior, New York: McGraw-Hill, 1922.

The Mechanistic Conception of Life is Loeb's most famous and influential work. It contains English translations of some of his previous publications in German.

External links

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