Franz Ritter von Soxhlet (12 January 1848 – 5 May 1926) was a German agricultural chemist and

inventor An invention is a unique or novel device, method, composition, idea, or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

Biography

Franz von Soxhlet was born on 12 January 1848 in

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, Moravia,

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and migrated with his family to the

German Confederation The German Confederation ( ) was an association of 39 predominantly German-speaking sovereign states in Central Europe. It was created by the Congress of Vienna in 1815 as a replacement of the former Holy Roman Empire, which had been dissolved ...

. He was the son of spinning industrialist Hubert Soxhlet, an immigrant from Dalhem near

Liège Liège ( ; ; ; ; ) is a City status in Belgium, city and Municipalities in Belgium, municipality of Wallonia, and the capital of the Liège Province, province of Liège, Belgium. The city is situated in the valley of the Meuse, in the east o ...

(in the former

Duchy of Brabant The Duchy of Brabant, a Imperial State, state of the Holy Roman Empire, was established in 1183. It developed from the Landgraviate of Brabant of 1085–1183, and formed the heart of the historic Low Countries. The Duchy comprised part of the Bu ...

). He gained a PhD at

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in 1872 with the dissertation ''Zur physiologischen Chemie der Milch''. In 1879, he became a professor of agricultural chemistry at the

Technical University of Munich The Technical University of Munich (TUM or TU Munich; ) is a public research university in Munich, Bavaria, Germany. It specializes in engineering, technology, medicine, and applied and natural sciences. Established in 1868 by King Ludwig II ...

. He invented the

Soxhlet extractor A Soxhlet extractor is a piece of laboratory apparatus invented in 1879 by Franz von Soxhlet. It was originally designed for the extraction of a lipid from a solid material. Typically, Soxhlet extraction is used when the desired compound has a ' ...

in 1879 and in 1886 he proposed

pasteurization In food processing, pasteurization (American and British English spelling differences#-ise, -ize (-isation, -ization), also pasteurisation) is a process of food preservation in which packaged foods (e.g., milk and fruit juices) are treated wi ...

be applied to milk and other beverages in order to prevent disease and spoilage. Soxhlet is also known as the first scientist who fractionated the milk proteins in

casein Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of ...

albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water- soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Alb ...

, globulin and lactoprotein. Furthermore, he described for the first time the sugar present in milk,

lactose Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from (Genitive case, gen. ), the Latin word for milk, plus the suffix ''-o ...

. The Soxhlet solution is an alternative to Fehling's solution for preparation of a comparable cupric/tartrate reagent to test for

reducing sugar A reducing sugar is any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a react ...

Death

He died on 5 May 1926 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 ...

, at the age of 78, and was buried alongside his wife at the Alter Friedhof Pöcking,

Starnberg Starnberg is a Town#Germany, town in Bavaria, Germany, some southwest of Munich. It is at the north end of Lake Starnberg, in the heart of the "Five Lakes Country", and serves as capital of the Starnberg (district), district of Starnberg. Recor ...

.Franz von Soxhlet
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Family

Franz was married to Helene Maria, née Dreßler (1847–1914). They had two children: Son Erich, Dipl.-Ing. in Munich, and daughter Helene (1881–1955), who married Lieutenant Colonel Walter von Lossow (1872–1943).

Honours (excerpt)

* Order of Saint Michael (Bavaria), Knight 2nd Class * Honorary doctorate (Dr. med. h. c.) from the University of Halle in 1894 * Awarded the honorary title of Privy Councilor (''Geheimer Hofrat'') in 1911

Sources

* Rosenau, M.J.: The Milk Question, Houghton Mifflin Company, Boston, 1913. * Soxhlet, F.: Die gewichtsanalytische Bestimmung des Milchfettes, Polytechnisches J. (Dingler's) 1879, 232, 461 * Rommel, Otto: Franz von Soxhlet Münchener Medizinische Wochenschrift 73 (1926) 994–995 * Österreichisches Biographisches Lexikon, XII. Band, chwarzMarie – Spannagel Rudolf, Wien 2005

References