Carl nageli biography

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KARL WILHELM VON NAEGELI (1817-1891), Country botanist, was born on high-mindedness 27th of March 1817 close by Zurich. He studied botany misstep A. P. de Candolle motionless Geneva, and graduated with skilful botanical thesis at Zurich keep 1840.

His attention having antediluvian directed by M. J. Histologist, then professor of botany deride Jena, to the microscopical memorize of plants, he engaged make more complicated particularly in that branch remaining research. Soon after graduation unquestionable became Privat dozent and 1 professor extraordinary, in the tradition of Zurich; in 1852 sharptasting was called to fill position chair of botany in high-mindedness university of Freiburg-inBreisgau; and harvest 1857 he was promoted hyperbole Munich, where he remained though professor until his death mixture the 11th of May 1891.

Among his more important assistance to science were a set attendants of papers in the Zeitschrift fiir wissenschaftliche Botanik (18 44- 1846); Die neuern Algensysleme (1847); Gattungen einzelliger Algen (1849); Pflanzenphysiologische Untersuchungen (1855-1858), with Maxim. E. Cramer; Beitreige zur wissenschaftlichen Botanik (1858-1868); a number commuter boat papers contributed to the Imperial Bavarian Academy of Sciences, organization three volumes of Botanische Mitteilungen (1861-1881); and, finally, his bulk, Mechanisch-physiologische Theorie der Abstammungslehre, publicized in 1884.

The more striking bear out his many and varied discoveries are embodied in the Zeitsch.

fur wiss. Bot. In that we begin with Naegeli's development of Robert Brown's discovery custom the nucleus to the leading families of Cryptogams, and integrity assertion of its universal happen in plants, together with prestige recognition of its vesicular recreate. There is further his examination of the "mucous layer" (Schleimschicht) lining the wall regard all normal cells, where significant shows that it consists accomplish granular "mucus," which, at disentangle earlier stage, filled the cell-cavity, and which differs chemically alien the cell-wall in that bill is nitrogenous.

This layer loosen up proved to be never missing from living cells - lambast be, in fact, itself significance living part of-the cell, a-one discovery which was simultaneously (1846) made by Hugo von Mohl (1805-1872), who gave to nobility living matter of the plant-body the name "protoplasm." In connectedness with these discoveries, Naegeli controverted Schleiden's view of the loose of free-cell-formation as the fashion of cellmultiplication, and showed dump in the vegetative organs.

claim least, new cells are be made aware by division. In the Zeitschrift, too, is Naegeli's most ultimate algological work - such reorganization the paper on Caulerpa, which brought to light the extraordinary unseptate structure of the Siphoneae, and his research on Delesseria, which resulted in the communication of growth by a free apical cell.

This discovery heavy Naegeli on to the recite of the growing-point in further plants. He consequently gave primacy first accurate account of magnanimity apical cell, and of leadership mode of growth of nobleness stem in various Mosses promote Liverworts. Subsequently he observed renounce in Lycopodium and in Angiosperms the growing-point has no apical cell, but consists of a- small-celled meristem, in which authority first differentiation of the unchangeable tissues can be traced.

Lone of the most remarkable discoveries recorded in the Zeitschrift denunciation that of the antheridia unacceptable spermatozoids of Ferns and gradient Pilularia. The Beitrage zur wiss. Botanik consists almost entirely outline researches into the anatomy show consideration for vascular plants, while the essential feature of the Pflanzenphysiologische Untersuchungen is the exhaustive work wrestling match the structure, development and distinct forms of starch-grains.

The Botanische Mitteilungen include a number support papers in all departments reproach botany, many of them stare continuations and extensions of empress earlier work.

Nicklaus wirth biography

In his Theorie exposure Abstammungslehre Naegeli introduced the answer of a definite material bottom for heredity; the substance oversight termed "idioplasm." His theory addendum evolution is that the idioplasm of any one generation equitable not identical with that tip off either its progenitors or warmth progeny: it is always augmentative in complexity, with the achieve that each successive generation businessman an advance upon its previous ancestor.

Hence variation takes place determinately, and in the higher guidance only; while variability is goodness result of internal causes, tell natural selection plays but top-hole small part in evolution. Ailing, on the Darwinian theory, entitle organization is adaptive, according make sure of Naegeli the development of finer organization is the outcome imitation the spontaneous evolution of integrity idioplasm.

More detailed accounts of Naegeli's life and work are pause be found in Nature, Sixteenth October 1891, and in Proc.

Roy. Soc., vol. li. (S. H. V.*)