Félix Dujardin

Félix Dujardin

Félix Dujardin (born April 5, 1801 in Tours , † April 8, 1860 in Rennes ) was a French naturalist , geologist , zoologist and botanist . Its official botanical author abbreviation is “ Dujard. ".

Life

Dujardin's father and grandfather were both watchmakers who were originally based in Lille . Felix Dujardin was involved in the craft for a while, resulting in remarkable manual dexterity.

With his two brothers Dujardin attended the classes of the Collège de Tours as a student. He was originally drawn to art, drawing in particular tied him. His interest in science was apparently first aroused by a surgeon, a friend of the family, and so he studied as an autodidact in the books on anatomy and natural history he had borrowed. Antoine François de Fourcroy's texts sparked his interest in chemistry. Chemistry became Dujardin's main interest for a time. A textbook by Louis Jacques Thénard also influenced its further development . Intending to study chemistry in the laboratories of Thénard in Paris, he began to prepare for the entrance examination to the École polytechnique . Dujardin failed the entrance exam in 1818.

A short episode of painting in François Gérard's studio followed. To earn a living, he soon took a job as a hydraulic engineer in Sedan . In 1823 he married Clémentine Grégoire. He returned to Tours, where he took over responsibility for a library. In his spare time he conducted various kinds of scientific studies. His publication on fossils in the Touraine Tertiary strata was valuable enough to caught the attention of Charles Lyell .

From 1826 to 1829 he taught applied science, geometry and chemistry in Tours. He also pursued studies in optics and crystallography and found time for botanical excursions that led to the publication of the Flore complète d'Indre-et Loire in 1833 with two co-authors . On the advice of the botanist Henri Dutrochet , he decided to specialize in zoology and move from Tours to Paris. For the next few years he and his family financed his life by writing scientific papers in magazines and encyclopedias.

In 1839, through his work in geology, he was appointed to the Chair of Geology and Mineralogy in the Faculty of Science at the University of Toulouse . In November 1840 he was appointed professor of zoology and botany and later dean of the faculty at the newly established faculty for natural sciences in Rennes . This position brought him some conflicts with his colleagues, so that he gave up this position in 1842. After his retirement, Dujardin became almost a hermit and spent his final years in Rennes in peace. Shortly before his death, he became a corresponding member of the Académie des sciences , twelve years after his name was first proposed.

Achievements in zoology

Dujardin is best known for his work on microscopic wildlife. In 1834 he suggested naming a group of unicellular organisms as rhizopods . When Dujardin observed the live foraminifera under the microscope , his attention was drawn to the activity of a contractile internal substance that spontaneously pushed through the pores of the calcareous shells in the form of pseudopodia . In 1835 he named the intracellular substance of these unicellular organisms (rhizopods) as a sarcode , which the botanist Hugo von Mohl later referred to as protoplasm . He called this sarcode, also gelée vivante in his memoirs in 1835 . This hypothesis led him to contradict the ideas of Christian Gottfried Ehrenberg - who mainly dealt with fossil radiolarians - that the microscopic organisms have the same organs as higher (multicellular) animals.

However, he did not succeed in integrating the concept of the sarcode into a general theory of the cell ( cell biology ). It was not until 1845 that Carl von Siebold published a text showing that the rhizopods or protozoa are unicellular organisms and thus cells that can live independently of one another.

Félix Dujardin saw single-celled rhizopods in the foraminifera , as he called them, with shells ( Rhizopodes á coquilles ). Incidentally, today the rhizopods are divided into three groups, such as the foraminifera , the heliozoa and the radiolarians , and that of the amoeba is also included as the fourth order . Whereby the taxon Rhizopoda from a phylogenetic point of view seems more polyphyletic and therefore not durable.

Fonts (selection)

• Mémoire sur les couches du sol en Touraine et descriptions des coquilles de la craie des faluns (1837). [1]
• Histoire naturelle des zoophytes. Infusoires, comprenant la physiologie et la classification de ces animaux, et la manière de les étudier à l'aide du microscope (1841). [2] doi: 10.5962 / bhl.title.10127 doi: 10.5962 / bhl.title.51143
• Nouveau manuel de l'observateur au microscope (1842). [3] doi: 10.5962 / bhl.title.51229
• Histoire naturelle des helminthes ou vers intestinaux . xvi, 654 + 15 pp. + Plates (1845). [4] [5] doi: 10.5962 / bhl.title.10123
• Histoire naturelle des zoophytes échinodermes: comprenant la description des crinoïdes, des ophiurides, des asterides, des échinides et des holothurides . Librairie encyclopédique de Roret, Paris 1862 doi: 10.5962 / bhl.title.10122
• Mémoire sur le system nerveux des insectes. In: Annales des sciences naturelles. Zoology (sub-series), 3rd series, Vol. 14 (1850), pp. 195-206.

Others

• KTE von Siebold: Textbook of the comparative anatomy of the vertebrate animals. Berlin 1845.
• L. Joubin: Félix Dujardin , in Archives de parasitologie, 4 (1901), 5-57.
• E. Beltrán: Felix Dujardin y su Histoire naturelle des Zoophytes. Infusoires, 1841, in Revista de la Sociedad mexicana de historia natural, 2 (1941), 221-232
• JR Baker: The Cell Theory: A Restatement, History, and Critique. Part II , in Quarterly Journal of the Microscopical Sciences, 90 (1949), 87-107

Web links

• Portrait of F. Dujardin
• Author entry at the IPNI

Individual evidence

1. ^ Felix Dujardin - Encyclopedia.com .
2. ^ KTE von Siebold: Textbook of the comparative anatomy of the vertebrate animals . Berlin 1845