Carl Wilhelm von Nägeli

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Carl Wilhelm von Nägeli

Carl Wilhelm von Nägeli (born March 27, 1817 in Kilchberg , † May 10, 1891 in Munich ) was a Swiss botanist . Its official botanical author's abbreviation is " Nägeli ".

Life

Nägeli was born the son of a doctor. He studied medicine in Zurich from 1836, but soon switched to botany and studied with Lorenz Oken and Oswald Heer , among others . From 1839 he studied at the University of Geneva with Alphonse Louis Pierre Pyrame de Candolle . It was 1840 in Zurich with a thesis on The Cirsien of Switzerland Dr. phil. PhD. After studying in Berlin in 1841, from 1842 he worked with Matthias Schleiden at the University of Jena .

In 1849 Nägeli was appointed associate professor at the University of Zurich and in 1852 was offered the chair of botany at the University of Freiburg im Breisgau . There he worked until 1856 and was then professor of general botany at the Eidgenössisches Polytechnikum (the predecessor of ETH Zurich ) and at the same time at the University of Zurich.

Nägeli spent most of his academic career at the Ludwig Maximilians University in Munich , where he worked as a professor for general botany and microscopy from 1857 until his retirement in 1889. He was a member of the Society of German Natural Scientists and Doctors . Since 1862 he was a full member of the Bavarian Academy of Sciences . In 1877 he was elected a foreign member of the Göttingen Academy of Sciences . In 1878 he was accepted into the American Academy of Arts and Sciences .

Carl Wilhelm von Nägeli was one of the most important botanists of the 19th century. During the time of his work, biology changed decisively. Matthias Schleiden and Theodor Schwann proved that all organisms build and develop from cells. Charles Darwin formulated his theory of descent . With the help of microscopic, biochemical and biophysical methods, new insights into the structures and functions of cells and tissues were gained. This made it possible to trace many processes in nature back to natural causes. The speculative theories of natural philosophy that had been widespread up to that point, including those of Nägeli's teacher Lorenz Oken , lost their influence on biological thinking.

The great importance of Carl Wilhelm von Nägeli for the further development of botany as a whole is demonstrated by the numerous students who later became famous researchers in various fields: the algae researcher Karl Eduard Cramer (1831–1901); the founder of the anatomy of mosses , Paul Günther Lorentz (1835–1881); Hubert Leitgeb (1835–1888), who researched the development of liverworts ; Simon Schwendener , who became famous as the founder of "physiological anatomy "; Carl Prantl , the fern researcher ; Julius Oscar Brefeld , who explained the development of many mushrooms ; and Carl Correns , one of the founders of genetics . Even Anton Rehmann studied for his habilitation at Nageli plant anatomy.

Honors

In honor of Naegeli was on February 8, 1955 in Cologne , a street near the Cologne Flora named after him. The plant genera Naegelia Zoll. & Moritzi from the family of the cross thorn plants (Rhamnaceae) and the algae genus Naegeliella Schroet. are named after him.

research

Carl Wilhelm von Nägeli wrote a paper on the formation of pollen at the age of 25 and described cell division with great accuracy. The “transitory cytoblasts” he described were later identified as chromosomes . He further investigated the process of osmosis in unicellular algae. Together with Hugo von Mohl , he was the first botanist to differentiate the plant cell wall from the inside of the plant cell and explained its growth through intussusception (storage).

For the first time he described the structure and function of the spermatozoids in the cryptogams and examined the importance of lower fungi for the development of infectious diseases . The monograph Die Hieracien Mitteleuropas (1885 to 1889) , written jointly with Albert Peter , became a permanent scientific inventory of botany .

Nägeli dealt particularly intensively with microscopy , which he and Simon Schwendener discussed in 1865 Das Mikoskop. Wrote theory and application of the same . In addition, in his handbook of microscopy , he presents the first comprehensive description of polarization optics and their application to plant objects.

Nägeli's genetic and cytological research led him to the realization that “when the organism reproduces, all of its properties are inherited as idioplasm ”. He introduced the concept of idioplasm to botany. This idioplasm should be that part of the plasma of the protoplast that contains the “real facilities”, today we would say the genotype . Nägeli writes: "In every germ cell the characteristics of all ancestors are included as a system".

With his micellar theory in 1858 he presented a hypothesis about the submicroscopic architecture of optically anisotropic biostructures and coined the term meristem . He postulated that all plasma substances “consist of the various modifications of the albuminate”. Their molecules should then "combined to form crystalline groups of molecules, mixed in soluble and insoluble form, to form a mostly semi-liquid, slimy mass". Further: “In the moistened state, each is surrounded by a covering of water; when dry they touch each other ”. The groups of molecules that he assumed contained 72 C atoms were called “ micelles ”. This hypothesis has proven to be correct in many points, for example with regard to the crystallinity of the cellulose fibrils and the amorphism and strong swellability of the "intermicellar substance", which corresponds to the cell wall basic substance known today.

In the work Mechanical-Physiological Theory of Descent Theory (1884), Nägeli laid down his views on evolutionary biology. Nägeli was convinced of a natural development of species (evolution) even before he became aware of Darwin's work, for example in his work Die Individualität in der Natur from 1856. When Darwin's " Origin of Species " (1859) appeared, he sat down intensively with the Deszendenzlehre apart, agreed with her, but found Darwin's interpretation (like this himself) of the transforming influence of the environment on the organism unsatisfactory and postulated an intermediate agent, the "idioplasm" (see above), so that the selection is based on "internal causes "designed individuals could work - a logical anticipation of the later genetic material! However, Nägeli did not recognize the importance of Gregor Mendel's work in this regard: In 1866 he had sent him one of the 40 reprints of his experiments on plant hybrids , the results of which contradicted Nägeli's theories (because N. did not yet reckon with distinct genes). In an accompanying letter, Mendel mentioned his attempts at hybridization with hawkweeds ( Hieracium ), which Nägeli knew particularly well. Apparently, Nägeli valued the value of Mendel's investigations little because they came from a “practitioner”: in his view, “practitioners” relied on experience without checking its accuracy - which was only “through the scientific experiment, the one with the so-called Attempt that practitioners have nothing in common ”(Nägeli, 1877), is possible. Nägeli himself undertook extensive cross-breeding experiments with Hieracium to check the theory of descent.

Nägeli, along with other researchers of his time, was an advocate of the pleomorphism concept, which subsequently lost its importance. For example, he thought - in contrast to Robert Koch - he observed that bacteria could become other species through disintegration and re-joining of the parts.

The term oligodynamy , which describes the damaging effect of metal cations (positively electrically charged metal ions), especially heavy metals , on living cells, also goes back to Nägeli .

Fonts (selection)

  • On the history of the development of pollen among the phanerogams . Orell, Füssli and Comp. , Zurich 1842 ( Google Books )
  • The individuality in nature with excellent consideration of the plant kingdom . Meter & Zeller, Zurich 1856 ( Google Books )
  • The growth of the stem and the root in vascular plants and the arrangement of the vascular cords in the stem . In: Contributions to Scientific Botany, 1, Wilhelm Engelmann , Leipzig 1858 ( Google Books )
  • Origin and concept of the natural history species . Munich, 1865 ( archive )
  • with Simon Schwendener : The microscope: theory and application of the same. Wilhelm Engelmann, Leipzig 1867 ( archive )
  • Fermentation theory: a contribution to molecular physiology. R. Oldenbourg, Munich, 1879 ( archive )
  • Mechanical-physiological theory of the theory of descent. R. Oldenbourg, Munich and Leipzig 1884 ( archive )
  • with Albert Peter : The hierarchies of Central Europe. Monographic processing of the piloselloids with special consideration of the Central European clans . R. Oldenbourg , Munich 1885 ( archive )

literature

Web links

Commons : Karl Wilhelm von Nägeli  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Members of the Society of German Natural Scientists and Doctors 1857
  2. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 176. (Date of birth and death, as well as subject area, are incorrectly reproduced here. See also obituary by Carl Wilhelm von Naegeli (PDF). Retrieved on 17 February 2017 . ).
  3. ^ Rüdiger Schünemann-Steffen: Cologne street names lexicon. Jörg-Rüshü-Selbstverlag, Cologne 2006. p. 381.
  4. ↑ Lotte Burkhardt: Directory of eponymous plant names - Extended Edition. Part I and II. Botanic Garden and Botanical Museum Berlin , Freie Universität Berlin , Berlin 2018, ISBN 978-3-946292-26-5 doi: 10.3372 / epolist2018 .
  5. ^ Iltis, Johann Gregor Mendel, Springer 1924, p. 126
personal data
SURNAME Nägeli, Carl Wilhelm von
BRIEF DESCRIPTION Swiss botanist
DATE OF BIRTH March 27, 1817
PLACE OF BIRTH Kilchberg near Zurich
DATE OF DEATH May 10, 1891
Place of death Munich