Félix Dujardin

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

Life

Dujardin father and grandfather were both watchmakers who were originally based in Lille. Felix Dujardin was a long time involved with in the craft, resulting in a remarkable manual dexterity.

With his two brothers Dujardin attended the classes of the Collège de Tours as a student. He was originally attracted to the arts, especially drawing bound him. His interest in science was evidently first awakened by a surgeon, a family friend and he studied as an autodidact in his borrowed books on anatomy and natural history. The texts of Antoine François de Fourcroy aroused his interest in chemistry. Chemical was for a time Dujardin main interest. Influence on its further development also had a textbook by Louis Jacques Thénard. With the intention of studying chemistry in the laboratories of Thénard in Paris, he began to prepare for the entrance examination at the École Polytechnique. Dujardin failed in 1818 in the entrance examination.

A brief episode with the painting in the studio of François Gérard joined them. To earn his living, he soon took on a role as hydraulic engineer in Sedan. In 1823 he married Clémentine Grégoire. He returned to Tours, where he took responsibility for a library. In his spare time he pursued scientific studies of various kinds. His earliest publication on the tertiary strata and fossils of the Touraine were valuable enough to attract the attention of Charles Lyell.

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

In 1839 he was appointed by his work in geology at the Department of Geology and Mineralogy at the Faculty of Sciences at the University of Toulouse. In November 1840 he was transferred to the newly established Faculty of Natural Sciences in Rennes as professor of zoology and botany, and later Dean of the Faculty. This position brings him some conflicts with his colleagues, so he gives up this position in 1842. After his retirement Dujardin was almost a recluse and spent his last 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 proposed for the first time.

Services in zoology

Dujardin is primarily known for his work on the microscopic fauna. So he proposes in 1834 to designate a group of unicellular organisms as rhizopods. As Dujardin watched the foraminifera in the living state under the microscope, his attention was on the activity of contractile internal substance which spontaneously urged through the pores of calcareous shells in the form of pseudopodia directed. He renamed in 1835, which later described by the botanist Hugo von Mohl as protoplasm, intracellular substance of these protozoa ( rhizopods ) as sarcode. He called this sarcode, 1835 in his memoirs also gelée vivante. This hypothesis led him to contradict the considerations of Christian Gottfried Ehrenberg - mainly focused on fossil radiolarians - namely that the microscopic organisms have the same organs as higher ( multicellular ) animals.

However, he failed to integrate the concept of sarcode in a general theory of the cell ( cell biology ). It was not until 1845 Carl von Siebold ) will publish a text by showing that the rhizopods or protozoa unicellular organisms and thus cells are able to live independently.

Félix Dujardin looked in the unicellular foraminifera rhizopods, as he called them, with shells ( Rhizopodes á coquilles ). You share today the way the rhizopods into three groups, the foraminifera, the Heliozoa and radiolarians, and expects more than fourth order nor that of the amoeba added. Where the taxon Rhizopoda seems more than polyphyletic and therefore not tenable from a phylogenetic point of view.

Writings (selection )

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

Others

• KTE von Siebold: Textbook of comparative anatomy of vertebrate animals Lossen. Berlin 1845.
• L. Joubin: Félix Dujardin, in Archives de parasitology, 4 ( 1901), 5-57.
• E. Beltrán: Felix Dujardin y su Histoire naturelle of 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 the Quarterly Journal of the Microscopical Sciences, 90 ( 1949), 87-107