Liebig Trademark 278153 For OXO, 1905
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Justus ''Freiherr'' von Liebig (12 May 1803 – 18 April 1873) was a
German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...
scientist A scientist is a person who Scientific method, researches to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engag ...
who made major contributions to the theory, practice, and pedagogy of chemistry, as well as to agricultural and
biological Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of ...
chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
; he is considered one of the principal founders of
organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...
. As a professor at the
University of Giessen University of Giessen, official name Justus Liebig University Giessen (), is a large public research university in Giessen, Hesse, Germany. It is one of the oldest institutions of higher education in the German-speaking world. It is named afte ...
, he devised the modern laboratory-oriented teaching method, and for such innovations, he is regarded as one of the most outstanding chemistry teachers of all time. He has been described as the "father of the
fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...
industry" for his emphasis on
nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
and
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
s as essential plant
nutrient A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s, and his popularization of the
law of the minimum Liebig's law of the minimum, often simply called Liebig's law or the law of the minimum, is a principle developed in agricultural science by Carl Sprengel (1840) and later popularized by Justus von Liebig. It states that growth is dictated not by ...
, which states that plant growth is limited by the scarcest nutrient resource, rather than the total amount of resources available. He also developed a manufacturing process for beef extracts, and with his consent a company, called Liebig Extract of Meat Company, was founded to exploit the concept; it later introduced the Oxo brand beef
bouillon cube A bouillon cube (also known as a stock cube) is dehydrated broth or stock formed into a small cube or other cuboid shape. The most common format is a cube about wide. It is typically made from dehydrated vegetables or meat stock, a small port ...
. He popularized an earlier invention for condensing vapors, which came to be known as the
Liebig condenser The Liebig condenser (, ) or straight condenser is a piece of laboratory equipment, specifically a condenser (laboratory), condenser consisting of a straight glass tube surrounded by a water jacket. In typical laboratory operation, such as distil ...
.


Early life and education

Justus Liebig was born in
Darmstadt Darmstadt () is a city in the States of Germany, state of Hesse in Germany, located in the southern part of the Frankfurt Rhine Main Area, Rhine-Main-Area (Frankfurt Metropolitan Region). Darmstadt has around 160,000 inhabitants, making it the ...
into the
middle-class The middle class refers to a class of people in the middle of a social hierarchy, often defined by occupation, income, education, or social status. The term has historically been associated with modernity, capitalism and political debate. Commo ...
family of Johann Georg Liebig and Maria Caroline Möser in early May 1803. His father was a
drysalter Drysalters were dealers in a range of chemical products, including glue, varnish, dye and colourings. They might supply salt or chemicals for preserving food and sometimes also sold pickles, dried meat or related items. The name ''drysalter'' or '' ...
and hardware merchant who compounded and sold paints, varnishes, and
pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...
s, which he developed in his own workshop. From childhood, Justus was fascinated with
chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
. At the age of 13, Liebig lived through the year without a summer, when the majority of food crops in the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
were destroyed by a
volcanic winter A volcanic winter is a reduction in global temperatures caused by droplets of sulfuric acid obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, sulfur-rich, particularly explosive volcanic eru ...
.
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
was among the hardest-hit nations in the global famine that ensued, and the experience is said to have shaped Liebig's later work. Due in part to Liebig's innovations in fertilizers and agriculture, the 1816 famine became known as "the last great
subsistence crisis A subsistence crisis affects individuals or communities unable to obtain basic necessities due to either man-made or natural factors such as inflation, drought or war."The European subsistence crisis of 1845–1850: a comparative perspective", h ...
in the Western world". Liebig attended grammar school at the Ludwig-Georgs-Gymnasium in Darmstadt, from the ages of 8 to 14. Leaving without a certificate of completion, he was apprenticed for several months to the
apothecary ''Apothecary'' () is an Early Modern English, archaic English term for a medicine, medical professional who formulates and dispenses ''materia medica'' (medicine) to physicians, surgeons and patients. The modern terms ''pharmacist'' and, in Brit ...
Gottfried Pirsch (1792–1870) in
Heppenheim Heppenheim (Bergstraße) () is the seat of Bergstraße district in Hesse, Germany, lying on the Bergstraße on the edge of the Odenwald. It is best known for being the birthplace of Sebastian Vettel, a four-time Formula One World Champion and ...
before returning home, possibly because his father could not afford to pay his
indentures An indenture is a legal contract that reflects an agreement between two parties. Although the term is most familiarly used to refer to a labor contract between an employer and a laborer with an indentured servant status, historically indentures we ...
(a legal
contract A contract is an agreement that specifies certain legally enforceable rights and obligations pertaining to two or more parties. A contract typically involves consent to transfer of goods, services, money, or promise to transfer any of thos ...
that reflects or covers a debt or purchase obligation). He worked with his father for the next two years, then attended the
University of Bonn The University of Bonn, officially the Rhenish Friedrich Wilhelm University of Bonn (), is a public research university in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the () on 18 October 1818 by Frederick Willi ...
, studying under
Karl Wilhelm Gottlob Kastner Karl Wilhelm Gottlob Kastner (31 October 1783 – 13 July 1857) was a German chemist, natural scientist and a professor of physics and chemistry. Biography Kastner received his doctorate in 1805 under the guidance of Johann Göttling and began l ...
, his father's business associate. When Kastner moved to the
University of Erlangen A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Univ ...
, Liebig followed him. Liebig left
Erlangen Erlangen (; , ) is a Middle Franconian city in Bavaria, Germany. It is the seat of the administrative district Erlangen-Höchstadt (former administrative district Erlangen), and with 119,810 inhabitants (as of 30 September 2024), it is the smalle ...
in March 1822, in part because of his involvement with the radical Korps Rhenania (a nationalist student organization), but also because of his hopes for more advanced chemical studies. The circumstances are clouded by possible scandal. Some scholars argue that he fled to Paris because of his involvement in radical student groups. In late October 1822, Liebig went to Paris to study on a grant obtained for him by Kastner from the Hessian government. He worked in the private laboratory of
Joseph Louis Gay-Lussac Joseph Louis Gay-Lussac ( , ; ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen by volume (with Alexander von Humboldt), f ...
and was also befriended by
Alexander von Humboldt Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 1769 – 6 May 1859) was a German polymath, geographer, natural history, naturalist, List of explorers, explorer, and proponent of Romanticism, Romantic philosophy and Romanticism ...
and
Georges Cuvier Jean Léopold Nicolas Frédéric, baron Cuvier (23 August 1769 – 13 May 1832), known as Georges Cuvier (; ), was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuv ...
(1769–1832). Liebig's doctorate from Erlangen was conferred on 23 June 1823, a considerable time after he left, as a result of Kastner's intervention on his behalf. Kastner pleaded that the requirement of a dissertation be waived and the degree granted ''in absentia''.


Research and development

Liebig left Paris to return to Darmstadt in April 1824. On 26 May 1824, at the age of 21 and with Humboldt's recommendation, Liebig became a professor ''extraordinarius'' at the
University of Giessen University of Giessen, official name Justus Liebig University Giessen (), is a large public research university in Giessen, Hesse, Germany. It is one of the oldest institutions of higher education in the German-speaking world. It is named afte ...
. Liebig's appointment was part of an attempt to modernize the University of Giessen and attract more students. He received a small stipend, without laboratory funding or access to facilities. The presence of existing faculty complicated his situation: Professor Wilhelm Zimmermann (1780–1825) taught general chemistry as part of the philosophy faculty, leaving medical chemistry and pharmacy to Professor Philipp Vogt in the medical faculty. Vogt was happy to support a reorganization in which pharmacy was taught by Liebig and became the responsibility of the faculty of arts, rather than the faculty of medicine. Zimmermann found himself competing unsuccessfully with Liebig for students and their lecture fees. He refused to allow Liebig to use existing space and equipment and finally committed
suicide Suicide is the act of intentionally causing one's own death. Risk factors for suicide include mental disorders, physical disorders, and substance abuse. Some suicides are impulsive acts driven by stress (such as from financial or ac ...
on 19 July 1825. The deaths of Zimmermann and Professor Blumhof, who taught technology and mining, opened the way for Liebig to apply for a full professorship. Liebig was appointed to the '' Ordentlicher'' chair in chemistry on 7 December 1825, receiving a considerably increased salary and a laboratory allowance. Liebig married Henriette "Jettchen" Moldenhauer (1807–1881), the daughter of a state official, in May 1826. They had five children: Georg (1827–1903), Agnes (1828–1862), Hermann (1831–1894), Johanna (1836–1925), and Marie (1845–1920). Although Liebig was Lutheran and Jettchen Catholic, their differences in religion appear to have been resolved amicably by bringing their sons up in the Lutheran faith and their daughters as Catholics.


Transforming chemistry education

Liebig and several associates proposed to create an institute for pharmacy and manufacturing within the university. The Senate, however, uncompromisingly rejected their idea, stating that training "apothecaries, soapmakers, beer-brewers, dyers and vinegar-distillers" was not the university's task. As of 17 December 1825, they ruled that any such institution would have to be a private venture. This decision worked to Liebig's advantage. As an independent venture, he could ignore university rules and accept matriculated and unmatriculated students. Liebig's institute was widely advertised in pharmaceutical journals and opened in 1826. Its classes in practical chemistry and laboratory procedures for chemical analysis were taught in addition to Liebig's formal courses at the university. From 1825 to 1835, the laboratory was housed in the guardroom of a disused barracks on the edge of town. The main laboratory space was about in size and included a small lecture room, a storage closet, and a main room with ovens and work tables. An open colonnade outside could be used for dangerous reactions. Liebig could work there with eight or nine students at a time. He lived in a cramped apartment with his wife and children on the floor above. Liebig was one of the first chemists to organize a laboratory in its present form, engaging with students in empirical research on a large scale through a combination of research and teaching. His methods of organic analysis enabled him to direct the analytical work of many graduate students. Liebig's students were from many of the German states, as well as Britain and the United States. They helped create an international reputation for their ''Doktorvater.'' His laboratory became renowned as a model institution for the teaching of practical chemistry. It was also significant for its emphasis on applying discoveries in fundamental research to the development of specific chemical processes and products. In 1833, Liebig convinced chancellor Justin von Linde to include the institute within the university. In 1839, he obtained government funds to build a lecture theatre and two separate laboratories designed by architect Paul Hofmann. The new chemistry laboratory featured innovative glass-fronted fume cupboards and venting chimneys. By 1852, when he left Giessen for Munich, more than 700 students of chemistry and pharmacy had studied with Liebig.


Instrumentation

A significant challenge facing 19th-century
organic chemists Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or is the product o ...
was the lack of instruments and methods of analysis to support accurate, replicable analyses of organic materials. Many chemists worked on the problem of organic analysis, including French
Joseph Louis Gay-Lussac Joseph Louis Gay-Lussac ( , ; ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen by volume (with Alexander von Humboldt), f ...
and Swedish
Jöns Jacob Berzelius Baron Jöns Jacob Berzelius (; 20 August 1779 – 7 August 1848) was a Swedish chemist. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. Berzelius became a memb ...
, before Liebig developed his version of an apparatus for determining the carbon, hydrogen, and oxygen content of organic substances in 1830. It involved an array of five glass bulbs, called a
Kaliapparat A kaliapparat is a laboratory device invented in 1831 by Justus von Liebig (1803–1873) for the analysis of carbon in organic compounds. The device, made of glass, consists of a series of five bulbs connected and arranged in a triangular shape. ...
, to trap the oxidation product of the carbon in the sample following its combustion. Before reaching the Kaliapparat, the combustion gases were conducted through a tube containing hygroscopic
calcium chloride Calcium chloride is an inorganic compound, a Salt (chemistry), salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with cal ...
, which absorbed and retained the oxidation product of the hydrogen of the sample, namely water vapor. Next, in the Kaliapparat,
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
was absorbed in a
potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...
solution in the three lower bulbs and used to measure the weight of carbon in the sample. For any substance consisting only of carbon, hydrogen, and oxygen, the percentage of oxygen was found by subtracting the carbon and hydrogen percentages from 100%; the remainder must be the percentage of oxygen. A charcoal furnace (a sheet steel tray in which the combustion tube was laid) was used for the combustion. Weighing carbon and hydrogen directly, rather than estimating them volumetrically, significantly increased the method's accuracy of measurement. Liebig's assistant, Carl Ettling, perfected glass-blowing techniques for producing the Kaliapparat and demonstrated them to visitors. Liebig's kaliapparat simplified the method of quantitative organic analysis and rendered it routine. Brock suggests that the availability of a superior technical apparatus was one reason why Liebig was able to attract so many students to his laboratory. His method of
combustion analysis Combustion analysis is a method used in both organic chemistry and analytical chemistry to determine the elemental composition (more precisely empirical formula) of a pure organic compound by combusting the sample under conditions where the resul ...
was used pharmaceutically, and certainly made possible many contributions to organic, agricultural and biological chemistry. Liebig also popularized the use of a counter-current water-cooling system for distillation, still referred to as a
Liebig condenser The Liebig condenser (, ) or straight condenser is a piece of laboratory equipment, specifically a condenser (laboratory), condenser consisting of a straight glass tube surrounded by a water jacket. In typical laboratory operation, such as distil ...
. Liebig himself attributed the vapor condensation device to German pharmacist
Johann Friedrich August Gottling Johann, typically a male given name, is the German form of ''Iohannes'', which is the Latin form of the Greek name ''Iōánnēs'' (), itself derived from Hebrew name '' Yochanan'' () in turn from its extended form (), meaning "Yahweh is Gracious" ...
, who had made improvements in 1794 to a design discovered independently by German chemist
Christian Ehrenfried Weigel Christian Ehrenfried von Weigel (24 May 1748 – 8 August 1831) was a German scientist and, beginning in 1774, a professor of chemistry, pharmacy, botany, and mineralogy at the University of Greifswald. Biography Born in Stralsund, in 1771 h ...
in 1771, by French scientist
P. J. Poisonnier P. is an abbreviation or acronym that may refer to: * Page (paper), where the abbreviation comes from Latin ''pagina'' * Paris Herbarium, at the ''Muséum national d'histoire naturelle'' * ''Pani'' (Polish), translating as Mrs. * The ''Pacific Rep ...
in 1779, and by Finnish chemist
Johan Gadolin Johan Gadolin (5 June 176015 August 1852) was a Finnish chemist, physicist and mineralogist. Gadolin discovered a " new earth" containing the first rare-earth compound yttrium, which was later determined to be a chemical element. He is also con ...
in 1791. Although it was not widely adopted until after Liebig's death, when safety legislation finally prohibited the use of mercury in making
mirror A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...
s, Liebig proposed a process for
silvering Silvering is the chemical process of coating a non-conductive substrate such as glass with a reflective substance, to produce a mirror. While the metal is often silver, the term is used for the application of any reflective metal. Process Mo ...
that eventually became the basis of modern mirror-making. In 1835, he reported that
aldehydes In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...
reduce
silver salts A silver halide (or silver salt) is one of the chemical compounds that can form between the element silver (Ag) and one of the halogens. In particular, bromine (Br), chlorine (Cl), iodine (I) and fluorine (F) may each combine with silver to produc ...
to metallic silver. After working with other scientists,
Carl August von Steinheil Carl August von Steinheil (12 October 1801 – 14 September 1870) was a German physicist, inventor, engineer and astronomer. Biography Steinheil was born in Ribeauvillé, Alsace. He studied law in Erlangen since 1821. He then studied astronomy ...
approached Liebig in 1856 to see if he could develop a silvering technique capable of producing high-quality optical mirrors for use in
reflecting telescopes A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...
. Liebig developed blemish-free mirrors by adding copper to ammoniated silver nitrate and sugar. An attempt to commercialize the process and "drive out mercury mirror-making and its injurious influence on workers' health" was unsuccessful. Liebig's mirrors struggled commercially due to poor glass, which produced an off-color, greenish-yellow reflection. Rudely, Liebig commented that Frenchwomen especially hated his mirrors because Frenchwomen already looked yellow and sickly, and the mirrors just reminded them how ugly they were.


Organic chemistry

One of Liebig's frequent collaborators was
Friedrich Wöhler Friedrich Wöhler Royal Society of London, FRS(For) HonFRSE (; 31 July 180023 September 1882) was a German chemist known for his work in both organic chemistry, organic and inorganic chemistry, being the first to isolate the chemical elements be ...
. They met in 1826 in Frankfurt, after independently reporting on the preparation of two substances,
cyanic acid Isocyanic acid is a chemical compound with the structural formula HNCO, which is often written as . It is a colourless, volatile and poisonous gas, condensing at 23.5 °C. It is the predominant tautomer and an isomer of cyanic acid ''(a ...
and
fulminic acid Fulminic acid is an acid with the formula HCNO, more specifically . It is an isomer of isocyanic acid () and of its elusive tautomer, cyanic acid (), and also of isofulminic acid (). Fulminate is the anion of any of its salts. For historic ...
, that apparently had the same composition, but very different characteristics. The
silver fulminate Silver fulminate (AgCNO) is the highly explosive silver salt of fulminic acid. Silver fulminate is a primary explosive, but has limited use as such due to its extreme sensitivity to impact, heat, pressure, and electricity. The compound becomes p ...
investigated by Liebig was explosive, whereas the
silver cyanate Silver cyanate is the cyanate salt of silver. It can be made by the reaction of potassium cyanate with silver nitrate in aqueous solution, from which it precipitates as a solid. : Alternatively, the reaction : analogous to the reaction used for ...
found by Wöhler was not. After reviewing the disputed analyses together, they agreed that both were valid. The discovery of these and other substances led
Jöns Jacob Berzelius Baron Jöns Jacob Berzelius (; 20 August 1779 – 7 August 1848) was a Swedish chemist. Berzelius is considered, along with Robert Boyle, John Dalton, and Antoine Lavoisier, to be one of the founders of modern chemistry. Berzelius became a memb ...
to suggest the idea of
isomers In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element – but distinct arrangements of atoms in space. ''Isomerism'' refers to the existence or possibili ...
, substances that are defined not simply by the number and kind of atoms in the molecule, but also by the arrangement of those atoms. In 1832, Liebig and Friedrich Wöhler published an investigation of the oil of bitter almonds. They transformed pure oil into several halogenated compounds, which were further transformed in other reactions. Throughout these transformations, "a single compound" (which they named
benzoyl In organic chemistry, benzoyl (, ) is the functional group with the formula and structure . It can be viewed as benzaldehyde missing one hydrogen. The benzoyl group has a mass of 105 amu. The term "benzoyl" should not be confused with benzyl ...
) "preserves its nature and composition unchanged in nearly all its associations with other bodies." Their experiments proved that a group of carbon, hydrogen, and oxygen atoms could behave like an element, take the place of an element, and can be exchanged for elements in
chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
s. This laid the foundation for the doctrine of compound radicals, which can be seen as an early step in the development of structural chemistry. The 1830s were a period of intense investigation of organic compounds by Liebig and his students, and of vigorous debate about the theoretical implications of their results. Liebig published on a wide variety of topics, personally averaging 30 papers per year between 1830 and 1840. Liebig not only isolated individual substances, but also studied their interrelationships and the ways in which they degraded and metamorphosed into other substances, looking for clues to the understanding of both chemical composition and physiological function. Other significant contributions by Liebig during this time include his examination of the nitrogen content of bases; the study of chlorination and the isolation of
chloral Chloral, also known as trichloroacetaldehyde or trichloroethanal, is the organic compound with the formula Cl3CCHO. This aldehyde is a colourless liquid that is soluble in a wide range of solvents. It reacts with water to form chloral hydrate, a o ...
(1832); the identification of the ethyl radical (1834); the oxidation of alcohol and formation of
aldehyde In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred ...
(1835); the polybasic theory of organic acids (1838); and the degradation of
urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...
(1837). Writing about the analysis of urine, a complex organic product, he made a declaration that reveals both the changes that were occurring in chemistry over a short time and the impact of his own work. At a time when many chemists such as
Jöns Jakob Berzelius Jöns is a Swedish given name and a surname. Notable people with the given name include: * Jöns Jacob Berzelius (1779–1848), Swedish chemist * Jöns Budde (1435–1495), Franciscan friar from the Brigittine monastery in NaantaliVallis Grati ...
still insisted on a hard and fast separation between the organic and inorganic, Liebig asserted: Liebig's arguments against any chemical distinction between living (physiological) and dead chemical processes proved a great inspiration to several of his students and others who were interested in
materialism Materialism is a form of monism, philosophical monism according to which matter is the fundamental Substance theory, substance in nature, and all things, including mind, mental states and consciousness, are results of material interactions. Acco ...
. Though Liebig distanced himself from the direct political implications of materialism, he tacitly supported the work of
Carl Vogt August Christoph Carl Vogt (; ; 5 July 1817 – 5 May 1895) was a German scientist, philosopher, popularizer of science, and politician who emigrated to Switzerland. Vogt published a number of notable works on zoology, geology and physiology. A ...
(1817–1895),
Jacob Moleschott Jacob Moleschott (; ; 9 August 1822 – 20 May 1893) was a Dutch physiologist and writer on nutrition and dietetics. He was known for his philosophical and political positions in regard to scientific materialism and against vitalism. He saw a nee ...
(1822–1893), and
Ludwig Büchner Friedrich Karl Christian Ludwig Büchner (; ; 29 March 1824 – 30 April 1899) was a German philosopher, physiologist and physician who became one of the exponents of 19th-century scientific materialism. Biography Büchner was born at Darmstadt ...
(1824–1899).


Plant nutrition

By the 1840s, Liebig was attempting to apply theoretical knowledge from organic chemistry to real-world problems of food availability. His book ''Die organische Chemie in ihrer Anwendung auf Agricultur und Physiologie'' (''Organic Chemistry in its Application to Agriculture and Physiology'') (1840) promoted the idea that chemistry could revolutionize agricultural practice, increasing yields and lowering costs. It was widely translated, vociferously critiqued, and highly influential. Liebig's book discussed chemical transformations within living systems, both plant and animal, outlining a theoretical approach to agricultural chemistry. The book's first part focused on plant nutrition; the second was on chemical mechanisms of putrefaction and decay. Liebig's awareness of both synthesis and degradation led him to become an early advocate of
conservation Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and manage ...
, promoting ideas such as the recycling of
sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewerage, sewer system. Sewage consists of wastewater discharged fro ...
. Liebig argued against prevalent theories about role of
humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...
in plant nutrition, which held that decayed plant matter was the primary source of carbon for plant nutrition. Fertilizers were believed to act by breaking down humus, making it easier for plants to absorb. Associated with such ideas was the belief that some sort of "vital force" distinguished reactions involving organic as opposed to inorganic materials. Early studies of photosynthesis had identified carbon, hydrogen, oxygen, and nitrogen as important, but disagreed over their sources and mechanisms of action. Carbon dioxide was known to be taken in and oxygen released during photosynthesis, but researchers suggested that oxygen was obtained from carbon dioxide, rather than from water. Hydrogen was believed to come primarily from water. Researchers disagreed about whether sources of carbon and nitrogen were atmospheric or soil-based. Nicolas-Théodore de Saussure's experiments, reported in ''Recherches Chimiques sur la Végétation'' (1804), suggested that carbon was obtained from atmospheric rather than soil-based sources. It also indicated that water was a likely source of hydrogen. He also studied the absorption of minerals by plants, and observed that mineral concentrations in plants tended to reflect their presence in the soil in which the plants were grown. However, the implications of De Saussure's results for theories of plant nutrition were neither clearly discussed nor easily understood. Liebig reaffirmed the importance of De Saussure's findings, and used them to critique humus theories, while regretting the limitations of De Saussure's experimental techniques. Using more precise methods of measurement as a basis for estimation, he pointed out contradictions such as the inability of existing soil humus to provide enough carbon to support the plants growing in it. By the late 1830s, researchers such as
Karl Sprengel Karl or Philipp Carl Sprengel (March 29, 1787 – April 19, 1859) was a German botanist from Schillerslage (now part of Burgdorf, Hanover). Sprengel worked under Albrecht Thaer (1752–1828) in Celle. He then worked from 1804 to 1808 wi ...
were using Liebig's methods of combustion analysis to assess manures, concluding that their value could be attributed to their constituent minerals. Liebig synthesized ideas about the mineral theory of plant nutrition and added his own conviction that inorganic materials could provide nutrients as effectively as organic sources. In his theory of mineral nutrients, Liebig identified the chemical elements of nitrogen (N), phosphorus (P), and potassium (K) as essential to plant growth. He reported that plants acquire carbon (C) and hydrogen (H) from the atmosphere and from water (H2O). In addition to emphasizing the importance of minerals in the soil, he argued that plants feed on nitrogen compounds derived from the air. This assertion was a source of contention for many years, and turned out to be true for legumes, but not for other plants. Liebig also popularized Carl Sprengel's "theorem of minimum" (known as the
law of the minimum Liebig's law of the minimum, often simply called Liebig's law or the law of the minimum, is a principle developed in agricultural science by Carl Sprengel (1840) and later popularized by Justus von Liebig. It states that growth is dictated not by ...
), stating that plant growth is not determined by the total resources available, but by the scarcest available resource. A plant's development is limited by the one essential mineral that is in the relatively shortest supply. This concept of limitation can be visualized as "Liebig's barrel", a metaphorical barrel in which each stave represents a different element. A nutrient stave that is shorter than the others will cause the liquid contained in the barrel to spill out at that level. This is a qualitative version of the principles used for determining the application of fertilizer in modern agriculture. ''Organic Chemistry'' was not intended as a guide to practical agriculture. Liebig's lack of experience in practical applications, and differences between editions of the book, fueled considerable criticism. Nonetheless, Liebig's writings had a profound impact on agriculture, spurring experiment and theoretical debate in Germany, England, and France. One of his most recognized accomplishments is the development of
nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
-based
fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...
. In the first two editions of his book (1840, 1842), Liebig reported that the atmosphere contained insufficient nitrogen, and argued that nitrogen-based fertilizer was needed to grow the healthiest possible crops. Liebig believed that nitrogen could be supplied in the form of
ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
, and recognized the possibility of substituting chemical fertilizers for natural ones (animal dung, etc.) He later became convinced that nitrogen was sufficiently supplied by precipitation of ammonia from the atmosphere, and argued vehemently against the use of nitrogen-based fertilizers for many years. An early commercial attempt to produce his own fertilizers was unsuccessful, due to lack of nitrogen in the mixtures. When tested in a farmer's field, Liebig's manure was found to have no appreciable effect. Liebig's difficulties in reconciling theory and practice reflected that the real world of agriculture was more complex than was at first realized. By the publication of the seventh German edition of ''Agricultural Chemistry'' he had moderated some of his views, admitting some mistakes and returning to the position that nitrogen-based fertilizers were beneficial or even necessary.He was instrumental in the use of
guano Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...
for nitrogen. In 1863 he published the book "Es ist ja die Spitze meines lebens" in which he revised his early perceptions, now appreciating soil life and in particular the biological N fixatio

Nitrogen fertilizers are now widely used throughout the world, and their production is a substantial segment of the chemical industry.


Plant and animal physiology

Liebig's work on applying chemistry to plant and animal physiology was especially influential. By 1842, he had published ''Chimie organique appliquée à la physiologie animale et à la pathologie'', published in English as '' Animal Chemistry, or, Organic Chemistry in its Applications to Physiology and Pathology'', presenting a chemical theory of metabolism. The experimental techniques used by Liebig and others often involved controlling and measuring diet, and monitoring and analyzing the products of animal metabolism, as indicators of internal metabolic processes. Liebig saw similarities between plant and animal metabolism, and suggested that nitrogenous animal matter was similar to, and derived from, plant matter. He categorized foodstuffs into two groups, nitrogenous materials which he believed were used to build animal tissue, and non-nitrogenous materials which he believed were involved in separate processes of respiration and generation of heat. French researchers such as
Jean-Baptiste Dumas Jean Baptiste André Dumas (; 14 July 180010 April 1884) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights (relative atomic masses) and molecular weights by measuri ...
and
Jean-Baptiste Boussingault Jean-Baptiste Joseph Dieudonné Boussingault (2 February 1801 – 11 May 1887) was a French chemist who made significant contributions to agricultural science, petroleum science and metallurgy. Biography Jean-Baptiste Boussingault – an agric ...
believed that animals assimilated sugars, proteins, and fats from plant materials and that animals could not synthesize complex molecules. Liebig's work suggested a common ability of plants and animals to synthesize complex molecules from simpler ones. His experiments on fat metabolism convinced him that animals must be able to synthesize fats from sugars and starches. Other researchers built upon his work, confirming the abilities of animals to synthesize sugar and build fat. Liebig also studied respiration, at one point measuring the "ingesta and excreta" of 855 soldiers, a bodyguard of the Grand Duke of Hessen-Darmstadt, for an entire month. He outlined an extremely speculative model of equations in which he attempted to explain how protein degradation might balance within a healthy body and result in pathological imbalances in cases of illness or inappropriate nutrition. This proposed model was justifiably criticized. Berzelius stingingly stated that "this facile kind of physiological chemistry is created at the writing table". Some of the ideas that Liebig had enthusiastically incorporated were not supported by further research. The third and last edition of ''Animal Chemistry'' (1846) was substantially revised and did not include the equations. The third area discussed in ''Animal Chemistry'' was fermentation and putrefaction. Liebig proposed chemical explanations for processes such as eremacausis (organic decomposition), describing the rearrangement of atoms as a result of unstable "affinities" reacting to external causes such as air or already decaying substances. Liebig identified the blood as the site of the body's "chemical factory", where he believed processes of synthesis and degradation took place. He presented a view of disease in terms of chemical process, in which healthy blood could be attacked by external contagia; secreting organs sought to transform and excrete such substances; and failure to do so could lead to their elimination through the skin, lungs, and other organs, potentially spreading contagion. Again, although the world was much more complicated than his theory, and many of his individual ideas were later proved wrong, Liebig managed to synthesize existing knowledge in a way that had implications for doctors, sanitarians, and social reformers. The English medical journal ''
The Lancet ''The Lancet'' is a weekly peer-reviewed general medical journal, founded in England in 1823. It is one of the world's highest-impact academic journals and also one of the oldest medical journals still in publication. The journal publishes ...
'' reviewed Liebig's work and translated his chemical lectures as part of its mission to establish a new era of medicine. Liebig's ideas stimulated medical research, led to the development of better techniques for testing experimental models of metabolism, and pointed to chemistry as fundamental to the understanding of health and disease. In 1850, Liebig investigated
spontaneous human combustion Spontaneous human combustion (SHC) is the pseudoscientific concept of the spontaneous combustion of a living (or recently deceased) human body without an apparent external source of ignition on the body. In addition to reported cases, descripti ...
, dismissing the simplistic explanations based on
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...
due to alcoholism.


Liebig and the chemistry of food


Methods of cookery

Liebig drew upon his work in plant nutrition and plant and animal metabolism to develop a theory of nutrition, which had implications for cookery. In his ''Researches on the Chemistry of Food'' (1847) Liebig argued that eating not only meat fibre, but also meat juices, which contained various inorganic chemicals, was important. These vital ingredients would be lost during conventional boiling or roasting in which cooking liquids were discarded. For optimum nutritional quality, Liebig advised that cooks should either sear the meat initially to retain fluids, or retain and use cooking liquids (as in soups or stews). Liebig was acclaimed in ''The Lancet'' for revealing "the true principles of cookery", and physicians promoted "rational diets" based on his ideas. Well-known British cookery writer
Eliza Acton Eliza Acton (17 April 1799 – 13 February 1859) was an English food writer and poet who produced one of Britain's first cookery books aimed at the domestic reader, '' Modern Cookery for Private Families''. The book introduced the now-un ...
responded to Liebig by modifying the cookery techniques in the third edition of her ''Modern Cookery for Private Families'', and subtitling the edition accordingly. Liebig's idea that "
searing Searing or pan searing is a technique used in grilling, baking, braising, roasting, sautéing, and the like, in which the surface of the food (usually meat such as beef, poultry, pork Pork is the culinary name for the meat of the ...
meat seals in the juices", though still widely believed, is not true.


Liebig's Extract of Meat Company

Building on his theories of the nutritional value of meat fluids, and seeking an inexpensive nutrition source for Europe's poor, Liebig developed a formula for producing beef extract. The details were published in 1847 so that "the benefit of it should ... be placed at the command of as large a number of persons as possible by the extension of the manufacture, and consequently a reduction in the cost". Production was not economically feasible in Europe, where meat was expensive, but in
Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...
and
New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...
, meat was an inexpensive byproduct of the leather industry. In 1865, Liebig partnered with Belgian engineer
George Christian Giebert George may refer to: Names * George (given name) * George (surname) People * George (singer), American-Canadian singer George Nozuka, known by the mononym George * George Papagheorghe, also known as Jorge / GEØRGE * George, stage name of Gior ...
, and was named scientific director of
Liebig's Extract of Meat Company Liebig's Extract of Meat Company, established in the United Kingdom, was the producer of LEMCO brand Liebig's Extract of Meat and the originator of Oxo meat extracts and Oxo beef stock cubes. It was named after Justus ''Freiherr'' von Liebig, ...
, located in
Fray Bentos Fray Bentos () is the capital city of the Río Negro Department, in south-western Uruguay, at the Argentina-Uruguay border, near the Argentine city of Gualeguaychú. Its port on the Uruguay River is one of the nation's most important harbours. T ...
in Uruguay. Other companies also attempted to market meat extracts under the name "Liebig's Extract of Meat". In Britain, a competitor's right to use the name was successfully defended on the grounds that the name had fallen into general use and become a
generic term Trademark distinctiveness is an important concept in the law governing trademarks and service marks. A trademark may be eligible for registration, or registrable, if it performs the essential trademark function, and has distinctive character. Re ...
before the creation of any particular company. The judge asserted that "Purchasers must use their eyes", and considered the presentation of the products to be sufficiently different to enable the discriminating consumer to determine which of the products bore Liebig's signature and was supported by Liebig himself. Liebig's company initially promoted their "meat tea" for its curative powers and nutritional value as a cheap, nutritious alternative to real meat. But such claims did not hold up to scrutiny. In 1868 the German physiologis
Edward Kemmerich
ran an experiment involving feeding the extract to dogs, every one of which died. After claims of its nutritional value were questioned, the company emphasized its convenience and flavor, marketing it as a comfort food. The Liebig company worked with popular cookery writers in various countries to popularize their products. German cookery writer
Henriette Davidis Johanna Friederika Henriette Katharina Davidis (1 March 1801 in Wengern – 3 April 1876 in Dortmund) was a German cookbook writer. Although many similar cookbooks had been published by then, amongst others Sophie Wilhelmine Scheibler's ''Allgeme ...
wrote recipes for ''Improved and Economic Cookery'' and other cookbooks. Katharina Prato wrote an Austro-Hungarian recipe book, ''Die Praktische Verwerthung Kochrecepte'' (1879). Hannah M. Young was commissioned in England to write ''Practical Cookery Book'' for the Liebig Company. In the United States,
Maria Parloa Maria Parloa (September 25, 1843 – August 21, 1909) was an American author of books on cooking and housekeeping, the founder of two cooking schools, a lecturer on food topics, and an early figure in the "domestic science" (later "home economics ...
extolled the benefits of Liebig's extract. Colorful calendars and trading cards were also marketed to popularize the product. The company also worked with British chemist
Henry Enfield Roscoe Sir Henry Enfield Roscoe (7 January 1833 – 18 December 1915) was a British chemist. He is particularly noted for early work on vanadium, photochemical studies, and his assistance in creating Oxo, in its earlier liquid form. Life and work ...
to develop a related product, which it registered some years after Liebig's death, under the " Oxo" trademark. Oxo was trademarked worldwide in 1899 and in the United Kingdom in 1900. Originally a liquid, Oxo was released in cubed solid form in 1911.


Marmite

Liebig studied other foods, as well. He promoted the use of baking powder to make lighter bread, studied the chemistry of coffee-making and
oatmeal Oatmeal is a preparation of oats that have been dehusked, steamed, and flattened, or a coarse flour of hulled oat grains ( groats) that have either been milled (ground), rolled, or steel-cut. Ground oats are also called white oats. Steel- ...
. He is considered to have made possible the invention of
Marmite Marmite ( ) is a British savoury food spread based on yeast extract, invented by the German scientist Justus von Liebig. It is made from by-products of beer brewing ( lees) and is produced by the British company Unilever. Marmite is a vegan ...
, because of his discovery that yeast could be concentrated to form
yeast extract Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture Growing media, media. They are often used to create savoury flavors and umami tast ...
. Infant Formula Liebig produced some of the world's first
infant formula Infant formula, also called baby formula, simply formula (American English), formula milk, baby milk, or infant milk (British English), is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, ...
, a breast-milk substitute for babies who could not breast-feed. However, the product proved controversial, even though Liebig did not make any royalties off it. Liebig first came up with the idea based on the struggles of his favorite daughter, Johanna, who struggled to breastfeed her daughter, Carolina, who was born in 1864. (Johanna did not want to seek a
wet-nurse A wet nurse is a woman who breastfeeds and cares for another's child. Wet nurses are employed if the mother dies, if she is unable to nurse the child herself sufficiently or chooses not to do so. Wet-nursed children may be known as "milk-siblin ...
, a common but controversial practice at the time.) Carolina, according to Liebig, thrived on the formula. But other scientists were skeptical. One of them, a French doctor in Paris named Jean-Anne-Henri Depaul, decided to test his formula on four infants whose mothers could not suckle. Liebig himself prepared the first batches of formula. Depaul first gave it to a set of
twin Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of Twin Last Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two ...
s, who were born somewhat
premature Premature may refer to: * ''Premature'' (2014 film), an American comedy film * ''Premature'' (2019 film), an American romantic drama film * '' PREMature'', a 2015 British television drama miniseries See also * Premature aging, of an organism * ...
and weighed 2.24
kilogram The kilogram (also spelled kilogramme) is the base unit of mass in the International System of Units (SI), equal to one thousand grams. It has the unit symbol kg. The word "kilogram" is formed from the combination of the metric prefix kilo- (m ...
s (4.93 pounds) and 2.64 kg (5.82 lbs.). Both died within two days. Depaul tried it on a third baby, born full-term at 3.37 kg (7.43 lbs.); it soon began passing green
starvation stools
and died within three days. A fourth child, weighing 2.76 kg, also developed green stools and died within four days. At this point, Depaul stopped the experiment. At first, Depaul kept the experiment to himself. But he attended a meeting of the
French Academy of Medicine French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), a ...
. And while didn't want to say anything at first, he felt he had to after another member of the Academy rose to speak, a
pharmacist A pharmacist, also known as a chemist in English in the Commonwealth of Nations, Commonwealth English, is a healthcare professional who is knowledgeable about preparation, mechanism of action, clinical usage and legislation of medications in ...
named Nicholas-Jean-Baptiste-Gaston Guibourt. Guibourt had grave doubts about Liebig's artificial
milk Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...
, calling it "fake milk" (in
French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...
, "lait factice"). As historia
Caroline Lieffers
has written, "He .e., Guibourtworried that the substance would either spoil in liquid form or lose its nutritive quality and convenience in solid form." Upon hearing Guibourt speak, Depaul felt it incumbent upon him to speak as well, and mentioned his experiments with Liebig's formula. Many
ethical Ethics is the philosophical study of moral phenomena. Also called moral philosophy, it investigates normative questions about what people ought to do or which behavior is morally right. Its main branches include normative ethics, applied e ...
questions were quickly raised. Publications in France generally supported Depaul, while German publications rallied to Liebig's defense.


Major works

Liebig founded the journal ''
Annalen der Chemie ''Justus Liebig's Annalen der Chemie'' (often cited as ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig wi ...
'', which he edited from 1832. Originally titled ''Annalen der Pharmacie'', it became ''Annalen der Chemie und Pharmacie'' to more accurately reflect its content. It became the leading journal of organic chemistry, and still exists, albeit under the name ''
European Journal of Organic Chemistry The ''European Journal of Organic Chemistry'' is a weekly peer-reviewed scientific journal covering organic chemistry. It is published by Wiley-VCH on behalf of Chemistry Europe. The journal, along with the ''European Journal of Inorganic Chemistr ...
'' after several mergers with other journals. The volumes from his lifetime are often referenced just as ''Liebigs Annalen''; following his death the title was officially changed to ''Justus Liebig's Annalen der Chemie''. Liebig published widely in ''Liebigs Annalen'' and elsewhere, in newspapers and journals. Most of his books were published concurrently in both German and English, and many were translated into other languages, as well. Some of his most influential titles include: * ''Ueber das Studium der Naturwissenschaften und über den Zustand der Chemie in Preußen'' (1840) Digital edition by the
University and State Library Düsseldorf The University and State Library Düsseldorf (, abbreviated ULB Düsseldorf) is a central service institution of Heinrich Heine University. Along with Bonn and Münster, it is also one of the three State Libraries of North Rhine-Westphalia. ...
* ''Die organische Chemie in ihrer Anwendung auf Agricultur und Physiologie''; in English, ''Organic Chemistry in its Application to Agriculture and Physiology'' (1840) * ''Chimie organique appliquée à la physiologie animale et à la pathologie''; in English, '' Animal chemistry, or, Organic chemistry in its applications to physiology and pathology'' (1842) * ''Familiar letters on chemistry and its relation to commerce, physiology and agriculture'' (1843) * ''Chemische Briefe'' (1844) Digital edition (1865) by the
University and State Library Düsseldorf The University and State Library Düsseldorf (, abbreviated ULB Düsseldorf) is a central service institution of Heinrich Heine University. Along with Bonn and Münster, it is also one of the three State Libraries of North Rhine-Westphalia. ...
In addition to books and articles, he wrote thousands of letters, most of them to other scientists. Liebig also directly influenced the German publication of
John Stuart Mill John Stuart Mill (20 May 1806 – 7 May 1873) was an English philosopher, political economist, politician and civil servant. One of the most influential thinkers in the history of liberalism and social liberalism, he contributed widely to s ...
's ''Logic.'' Liebig had a close friendship with the Vieweg family publishing house. He arranged for his former student Jacob Schiel (1813–1889) to translate Mill's important work for German publication. Liebig liked Mill's ''Logic'' in part because it promoted science as a means to social and political progress, but also because Mill featured several examples of Liebig's research as an ideal for the scientific method. In this way, he sought to reform politics in the German states.


Later life

In 1852, after asking
Hermann Kopp Hermann Kopp (born 21 August 1954, in Stuttgart) is a German composer and musician, presently living in Barcelona, Spain. Biography In the early eighties, Kopp released two vinyl records with a sound that can be vaguely classified as electroni ...
to take over management of the ''Annalen der Chemie'', Liebig accepted an appointment from King Maximilian II of Bavaria to the
Ludwig Maximilian University of Munich The Ludwig Maximilian University of Munich (simply University of Munich, LMU or LMU Munich; ) is a public university, public research university in Munich, Bavaria, Germany. Originally established as the University of Ingolstadt in 1472 by Duke ...
. He also became the Royal scientific advisor to King Maximilian II, who hoped to transform the University of Munich into a center for scientific research and development. In part, Liebig accepted the post because, at age 50, he was finding supervision of large numbers of laboratory students increasingly difficult. His new accommodations in Munich reflected this shift in focus. They included a comfortable house suitable for extensive entertaining, a small laboratory, and a newly built lecture theatre capable of holding 300 people with a demonstration laboratory at the front. There, he gave lectures to the university and fortnightly to the public. In his position as a promoter of science, Liebig was appointed president of the
Bavarian Academy of Sciences and Humanities The Bavarian Academy of Sciences and Humanities () is an independent public institution, located in Munich. It appoints scholars whose research has contributed considerably to the increase of knowledge within their subject. The general goal of th ...
, becoming perpetual president of the Royal Bavarian Academy of Sciences in 1858. In the 1850s, Liebig moved next door to the noted
classics Classics, also classical studies or Ancient Greek and Roman studies, is the study of classical antiquity. In the Western world, ''classics'' traditionally refers to the study of Ancient Greek literature, Ancient Greek and Roman literature and ...
scholar and
philologist Philology () is the study of language in oral and written historical sources. It is the intersection of textual criticism, literary criticism, history, and linguistics with strong ties to etymology. Philology is also defined as the study of ...
Friederich Thiersch in the city of
Munich Munich is the capital and most populous city of Bavaria, Germany. As of 30 November 2024, its population was 1,604,384, making it the third-largest city in Germany after Berlin and Hamburg. Munich is the largest city in Germany that is no ...
. Liebig had previously scorned philologists like Thiersch in articles. (Liebig promoted science over supposedly impractical fields like the classics.) But Liebig's most beloved daughter, Johanna, fell in love with Thiersch's second son, Karl, who had studied medicine in several cities, including Berlin and Vienna. Johanna and Karl reportedly had a happy marriage, producing six children: four daughters and two sons. It was fairly common for the sons and daughters of academics to marry in Germany then. Liebig enjoyed a personal friendship with Maximilian II, who died on 10 March 1864. After Maximilian's death, Liebig and other liberal Protestant scientists in Bavaria were increasingly opposed by
ultramontane Ultramontanism is a clerical political conception within the Catholic Church that places strong emphasis on the prerogatives and powers of the Pope. It contrasts with Gallicanism, the belief that popular civil authority—often represented by ...
Catholics. Liebig died in
Munich Munich is the capital and most populous city of Bavaria, Germany. As of 30 November 2024, its population was 1,604,384, making it the third-largest city in Germany after Berlin and Hamburg. Munich is the largest city in Germany that is no ...
in 1873, and is buried in the
Alter Südfriedhof The Alter Südfriedhof (''Old South Cemetery'') also known as "Alter Südlicher Friedhof" is a cemetery in Munich, Germany. It was founded by Albert V, Duke of Bavaria, Duke Albrecht V as a plague cemetery in 1563 about half a kilometer so ...
in Munich.


Awards and honors

Liebig was elected a member of the
Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...
in 1837. He became a first-class member of the
Ludwig Order The Ludwig Order (), was an order of the Grand Duchy of Hesse which was awarded to meritorious soldiers and civilians from 1807 to 1918. History The order was founded by Ludwig I, Grand Duke of Hesse and by Rhine as an order of merit without name ...
, founded by
Ludwig I Ludwig I or Louis I (; 25 August 1786 – 29 February 1868) was King of Bavaria from 1825 until the 1848 revolutions in the German states. When he was crown prince, he was involved in the Napoleonic Wars. As king, he encouraged Bavaria's ind ...
, and awarded by
Ludwig II Ludwig II (Ludwig Otto Friedrich Wilhelm; 25 August 1845 – 13 June 1886), also called the Swan King or the Fairy Tale King (), was King of Bavaria from 1864 until his death in 1886. He also held the titles of Count Palatine of the Rhine, Duk ...
on 24 July 1837. In 1838, he became a correspondent of the Royal Institute of the Netherlands; when that became the
Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences (, KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed in the Trippenhuis in Amsterdam. In addition to various advisory a ...
in 1851, he joined as a foreign member. The British
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
awarded him the
Copley Medal The Copley Medal is the most prestigious award of the Royal Society of the United Kingdom, conferred "for sustained, outstanding achievements in any field of science". The award alternates between the physical sciences or mathematics and the bio ...
"for his discoveries in organic chemistry, and particularly for his development of the composition and theory of organic radicals" in 1840. In 1841, botanist
Stephan Friedrich Ladislaus Endlicher Stephan Friedrich Ladislaus Endlicher, also known as Endlicher István László (24 June 1804 – 28 March 1849), was an Austrian botanist, numismatist and Sinologist. He was a director of the Botanical Garden of Vienna. Biography Endlicher ...
(1804–1849) published a genus of
flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...
s from
Malesia Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms. It is a phytogeographical floristic region in the Paleotropical kingdom. It was first recognized as a distinct region ...
, belonging to the family
Gesneriaceae Gesneriaceae, the gesneriad family, is a family (biology), family of flowering plants consisting of about 152 genera and ca. 3,540 species in the tropics and subtropics of the Old World (almost all Didymocarpoideae) and the New World (most Ges ...
, as ''
Liebigia ''Liebigia'' is a genus of flowering plants belonging to the family Gesneriaceae. It is native to Java, Sumatera and Lesser Sunda Islands. The genus name of ''Liebigia'' is in honour of Justus von Liebig (1803–1873), a German scientist who mad ...
'' in his honour.
King Ludwig II of Bavaria Ludwig II (Ludwig Otto Friedrich Wilhelm; 25 August 1845 – 13 June 1886), also called the Swan King or the Fairy Tale King (), was King of Bavaria from 1864 until his death in 1886. He also held the titles of Count Palatine of the Rhine, Duke ...
ennobled Liebig on 29 December 1845, conferring on him the hereditary title of ''
Freiherr (; male, abbreviated as ), (; his wife, abbreviated as , ) and (, his unmarried daughters and maiden aunts) are designations used as titles of nobility in the German-speaking areas of the Holy Roman Empire, the Austro-Hungarian Empire and in ...
''
von The term () is used in German surnames either as a nobiliary particle indicating a noble patrilineality, or as a simple preposition used by commoners that means or . Nobility directories like the often abbreviate the noble term to ''v.'' ...
Liebig. In English, the closest translation is
Baron Baron is a rank of nobility or title of honour, often Hereditary title, hereditary, in various European countries, either current or historical. The female equivalent is baroness. Typically, the title denotes an aristocrat who ranks higher than ...
von Liebig. In 1850, he received the French ''
Légion d'honneur The National Order of the Legion of Honour ( ), formerly the Imperial Order of the Legion of Honour (), is the highest and most prestigious French national order of merit, both military and Civil society, civil. Currently consisting of five cl ...
'', presented by chemist
Jean-Baptiste Dumas Jean Baptiste André Dumas (; 14 July 180010 April 1884) was a French chemist, best known for his works on organic analysis and synthesis, as well as the determination of atomic weights (relative atomic masses) and molecular weights by measuri ...
, the French trade minister. He was honored with the Prussian Order of Merit for Science by
Friedrich Wilhelm IV of Prussia Frederick William IV (; 15 October 1795 – 2 January 1861), the eldest son and successor of Frederick William III of Prussia, was King of Prussia from 7 June 1840 until his death on 2 January 1861. Also referred to as the " romanticist on the t ...
in 1851. He was elected as a member of the
American Philosophical Society The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publicat ...
in 1862. In 1869, Liebig was awarded the Albert Medal by the
Royal Society of Arts The Royal Society for the Encouragement of Arts, Manufactures and Commerce, commonly known as the Royal Society of Arts (RSA), is a learned society that champions innovation and progress across a multitude of sectors by fostering creativity, s ...
, "for his numerous valuable researches and writings, which have contributed most importantly to the development of food-economy and agriculture, to the advancement of chemical science, and to the benefits derived from that science by Arts, Manufactures, and Commerce."


Posthumous honors

Liebig's portrait appeared on the banknote issued by the
Reichsbank The ''Reichsbank'' (; ) was the central bank of the German Empire from 1876 until the end of Nazi Germany in 1945. Background The monetary institutions in Germany had been unsuited for its economic development for several decades before unifica ...
from 1935 until 1945. Printing ceased in 1945 but the note remained in circulation until the issue of the
Deutsche Mark The Deutsche Mark (; "German mark (currency), mark"), abbreviated "DM" or "D-Mark" (), was the official currency of West Germany from 1948 until 1990 and later of unified Germany from 1990 until the adoption of the euro in 2002. In English, it ...
on 21 June 1948. In 1946, after the end of World War II, the University of Giessen was officially renamed after him, ''"Justus-Liebig-Universität Giessen"''. In 1953, the West German
post office A post office is a public facility and a retailer that provides mail services, such as accepting letter (message), letters and parcel (package), parcels, providing post office boxes, and selling postage stamps, packaging, and stationery. Post o ...
issued a stamp in his honor. In 1953, the third General Assembly of the International Scientific Centre of Fertilizers (CIEC), founded in 1932, was organized in Darmstadt to honor Justus von Liebig on the 150th anniversary of his birth. A portrait of Liebig hangs in the
Burlington House Burlington House is a building on Piccadilly in Mayfair, London. It was originally a private English Baroque and then Neo-Palladian mansion owned by the Earl of Burlington, Earls of Burlington. It was significantly expanded in the mid-19th cent ...
headquarters of the
Royal Society of Chemistry The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the ...
. It was presented to the society's forerunner, the
Chemical Society The Chemical Society was a scientific society formed in 1841 (then named the Chemical Society of London) by 77 scientists as a result of increased interest in scientific matters. Chemist Robert Warington was the driving force behind its creation. ...
, by his god-daughter, Mrs Alex Tweedie, née Harley, daughter of Emma Muspratt.


Liebig medals

Some organizations have granted medals in honor of Liebig. In 1871, the Versammlung deutscher Land- und Forstwirte (Assembly of German Farmers and Foresters) was first awarded a Liebig Gold Medal, given to Theodor Reuning. The image was struck from a portrait commissioned in 1869 from Friedrich Brehmer. For several years, the Liebig Trust Fund, established by Baron Liebig, was administered by the
Royal Bavarian Academy of Sciences The Bavarian Academy of Sciences and Humanities () is an independent public institution, located in Munich. It appoints scholars whose research has contributed considerably to the increase of knowledge within their subject. The general goal of th ...
at Munich and members of the Liebig family. They were empowered to award gold and silver Liebig Medals to deserving German scientists "for the purpose of encouraging research in agricultural science". Silver medals could be awarded to scientists from other countries. Some of those who received medals include: * 1893, silver, Sir John Lawes and
Joseph Henry Gilbert Sir Joseph Henry Gilbert (1 August 1817 – 23 December 1901) was an English chemist, noteworthy for his long career spent improving the methods of practical agriculture. Along with J.B. Lawes, he conducted experiments at Rothamstead for forty ...
, England * 1894, silver, Professor
Eugene Woldemar Hilgard Eugene Woldemar Hilgard (January 5, 1833 – January 8, 1916) was a German-American expert on pedology (the study of soil resources). An authority on climate as a soil forming factor, soil chemistry and reclamation of alkali soils, he is consid ...
, United States, "for meritorious work in the investigation of the physical and chemical properties of soils." * 1896, gold, Professor
Friedrich Stohmann Friedrich Karl Adolf Stohmann (25 April 1832 – 1 November 1897) was a German agricultural chemist. Biography He was born in Bremen and studied at Göttingen, where he became member of Burschenschaft Hannovera (fraternity), and London. He was T ...
, professor of agricultural chemistry in
Leipzig University Leipzig University (), in Leipzig in Saxony, Germany, is one of the world's oldest universities and the second-oldest university (by consecutive years of existence) in Germany. The university was founded on 2 December 1409 by Frederick I, Electo ...
. * 1899, gold, Albert Schultz-Lupitz, Germany * 1908, gold,
Max Rubner Max Rubner (2 June 1854, Munich27 April 1932, Berlin) was a German physiologist and hygienist. Academic career He studied at the University of Munich and worked as an assistant under Adolf von Baeyer and Carl von Voit (doctorate 1878). Later ...
, Germany In 1903, the Verein deutscher Chemiker (Association of German Chemists) also had a medal struck using Brehmer's portrait. Their
Liebig Medal The Liebig Medal (German: ''Liebig-Denkmünze'') was established by the Society of German Chemists () in 1903 to celebrate the centenary of Justus von Liebig. Since 1946 it has been awarded by the Society of German Chemists (''Gesellschaft Deutsc ...
was first awarded in 1903 to
Adolf von Baeyer Johann Friedrich Wilhelm Adolf von Baeyer (; 31 October 1835 – 20 August 1917) was a German chemist who synthesised indigo dye, indigo and developed a Von Baeyer nomenclature, nomenclature for cyclic compounds (that was subsequently extended a ...
, and in 1904 to Dr. Rudolf Knietsch of the Badische Anilin- und Soda-Fabrik. , it continues to be awarded. At the third World Congress of CIEC, held at Heidelberg in 1957, the "Sprengel-Liebig Medal" was awarded to Dr. E. Feisst, president of CIEC, for outstanding contributions in agricultural chemistry.


See also

*
History of soil science The early concepts of soil were based on ideas developed by a German chemist, Justus von Liebig (1803–1873), and modified and refined by agricultural scientists who worked on samples of soil in laboratories, greenhouses, and on small field plots. ...
*
List of chemists This is a list of chemists. It should include those who have been important to the development or practice of chemistry. Their research or application has made significant contributions in the area of basic or applied chemistry. __NOTOC__ A * Ri ...


Notes


References


Sources

* * * * * * * * * * * * Rossiter, Margaret (1975) * * * * * *


External links

* * * *
Justus Liebig, German chemist (1803–73)
from the Encyclopædia Britannica, 10th Edition (1902).
The National Agricultural Center and Hall of Fame
* * * {{DEFAULTSORT:Liebig, Justus Von 1803 births 1873 deaths 19th-century German chemists 19th-century German inventors German soil scientists Scientists from Darmstadt People from the Grand Duchy of Hesse German barons University of Bonn alumni University of Erlangen–Nuremberg alumni Academic staff of the University of Giessen Academic staff of the Ludwig Maximilian University of Munich Recipients of the Copley Medal Recipients of the Pour le Mérite (civil class) Members of the Royal Netherlands Academy of Arts and Sciences Members of the Royal Swedish Academy of Sciences Foreign members of the Royal Society Foreign associates of the National Academy of Sciences Corresponding members of the Saint Petersburg Academy of Sciences Burials at the Alter Südfriedhof Members of the Bavarian Academy of Sciences International members of the American Philosophical Society