NAEGELI, KARL WILHELM VON Swiss botanist, was born on March 26, 1817, near ZUrich. He studied botany under A. P. de Candolle at Geneva, graduated at Zurich in 1840, then devoted himself to the microscopical study of plants. Soon after graduation he became Privatdozent and subsequently professor extraordinary, in the University of Zurich. He was later called to fill the chair of botany in the universities of Frei burg (1852), and Munich (1858), where he died on May 1o, 1891.
Naegeli made many important and varied discoveries. He extended Robert Brown's discovery of the nucleus to the prin cipal families of Cryptogams and asserted that it is present in all plants. He investigated the "mucous layer" (Schleimschicht) in cells and showed this to be the living matter of the cell. This discovery was made independently and at the same time by Hugo von Mohl (1805-1872), who called the living substance "proto plasm." Naegeli also investigated the mode of growth in a large number of plants belonging to the algae, mosses, liverworts and angiosperms. He discovered the spermatozoids and antheridia of
ferns. He also wrote papers on the anatomy of vascular plants and on the structure, development and various forms of starch grains. In his last book he introduced the idea of a substance which he called "idioplasm" as the definite material basis of heredity.
Among his more important contributions to science were a series of papers in the Zeitschrift fiir wissenschaftliche Botanik (1844-46) ; Die neuern Algensysteme (1847) ; Gattungen einzelliger Algen (1849) ; Pflanzenphysiologische Untersuchungen (1855-58), with C. E. Cramer; Beitriige zur wissenschaftlichen Botanik (1858-68) ; a number of papers contributed to the Royal Bavarian academy of sciences, forming three volumes of Botanische Mitteilungen (1861-81) ; and, finally, his vol ume, Mechanisch-physiologische Theorie der Abstammungslehre, pub lished in More detailed accounts of Naegeli's life and work are to be found in Nature, Oct. 16, 1891, and in Proc. Roy. Soc., vol. li.