Gustav Jäger (June 23, 1832 – May 13, 1917) was a German

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

and

hygienist Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refer ...

Biography

He was born at the historic Pfarrhaus in the village of Bürg, Neuenstadt am Kocher in

Württemberg Württemberg ( ; ) is a historical German territory roughly corresponding to the cultural and linguistic region of Swabia. The main town of the region is Stuttgart. Together with Baden and Province of Hohenzollern, Hohenzollern, two other histo ...

. After studying

medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

Tübingen Tübingen (; ) is a traditional college town, university city in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, and developed on both sides of the Neckar and Ammer (Neckar), Ammer rivers. about one in ...

, he became a teacher of

zoology Zoology ( , ) is the scientific study of animals. Its studies include the anatomy, structure, embryology, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and ...

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

. In 1868, he was appointed professor of zoology at the academy of Hohenheim, and subsequently he became teacher of zoology and

anthropology Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, society, societies, and linguistics, in both the present and past, including archaic humans. Social anthropology studies patterns of behav ...

Stuttgart Stuttgart (; ; Swabian German, Swabian: ; Alemannic German, Alemannic: ; Italian language, Italian: ; ) is the capital city, capital and List of cities in Baden-Württemberg by population, largest city of the States of Germany, German state of ...

Polytechnic and professor of physiology at the

Veterinary Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in non-human animals. The scope of veterinary medicine is wide, covering all animal species, both ...

School. In 1884, he abandoned teaching and started practice as a physician in Stuttgart. He wrote various works on biological subjects, including ''Die Darwinsche Theorie und ihre Stellung zu Moral und Religion'' (1869), and ''Lehrbuch der allgemeinen Zoologie'' (1871–1878). Jäger was an early supporter of

Darwinism ''Darwinism'' is a term used to describe a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others. The theory states that all species of organisms arise and develop through the natural sel ...

. In 1876, he suggested a hypothesis in explanation of

heredity Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic infor ...

, resembling the

germ plasm Germ plasm () is a biological concept developed in the 19th century by the German biologist August Weismann. It states that heritable information is transmitted only by germ cells in the gonads (ovaries and testes), not by somatic cells. The ...

theory subsequently elaborated by

August Weismann August Friedrich Leopold Weismann (; 17 January 18345 November 1914) was a German evolutionary biology, evolutionary biologist. Fellow German Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charl ...

, to the effect that the germinal

protoplasm Protoplasm (; ) is the part of a cell that is surrounded by a plasma membrane. It is a mixture of small molecules such as ions, monosaccharides, amino acids, and macromolecules such as proteins, polysaccharides, lipids, etc. In some definitions ...

retains its specific properties from generation to generation, dividing in each reproduction into an ontogenetic portion, out of which the individual is built up, and a phylogenetic portion, which is reserved to form the reproductive material of the mature offspring. GustJaeger

In ''Die Entdeckung der Seele'' ("The Discovery of The Soul", 1878), Jäger advanced the first crude version of the

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

concept. His postulated skin, "anthropines," popularly dubbed as "lust compounds," came astoundingly close to reality but the idea was too far ahead of the possibilities of chemistry and the life sciences at this time to be corroborated by experiments. The system of clothing associated with his name originates from ''Die Normalkleidung als Gesundheitsschutz'' ("Standardized Apparel For Health Protection" (1880)), wherein he advocated the wearing of rough fabrics, such as wool, "close to the skin," objecting especially to the use of any kind of plant fibre. The teachings of Jäger inspired the creation of the Jaeger clothing brand. From the 1860s on, Jäger immersed himself in popularizing science through print media, associations, and the founding of a public aquarium and small zoo in Vienna. In 1881, he founded his own magazine devoted to spreading his idea about health reform (''Prof. Dr. G. Jägers Monatsblatt''). He also was a very active

entomologist Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...

specialising in

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s particularly

Buprestidae Buprestidae is a family (biology), family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy Iridescence, iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the lar ...

and

Scarabaeidae The family Scarabaeidae, as currently defined, consists of over 35,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change. Several groups formerly tre ...

. He wrote with Carl Gustav Calwer ''Käferbuch-Naturgeschichte der Käfer Europas'' (''Beetle Book: Natural History of Europe's Beetles''). This very popular work was successively reprinted until 1916. His beetle collection is in the Stuttgart Natural History Museum.Staatliche Museen für Naturkunde Baden-Württemberg
at www.naturkundemuseum-bw.de

Notes

References

Andreas Daum Andreas W. Daum is a German-American historian who specializes in modern German and transatlantic history, as well as the history of knowledge and global exploration. Daum received his Ph.D. summa cum laude in 1995 from the Ludwig Maximilian Unive ...

, ''Wissenschaftspopularisierung im 19. Jahrhundert: Bürgerliche Kultur, naturwissenschaftliche Bildung und die deutsche Öffentlichkeit, 1848–1914''. Munich: Oldenbourg, 1998. *Schawaller, W. 1994: äger, G.''Stuttg. Beitr. Naturk. Ser. A (Biol.), Stuttgart'' (Nr. 508 1-40) *Schenkling, S. 1933: äger, G.''Ent. Blätter'' 29 28-30 *

External links

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Portrait {{DEFAULTSORT:Jager, Gustav 1832 births 1917 deaths People from Neuenstadt am Kocher People from the Kingdom of Württemberg 19th-century German biologists German entomologists Physicians from Stuttgart