Botanist English, discoverer of the nucleus cell, drive of the natural system of plant taxonomy and discoverer of the so-called Brownian motion.
He was born in Montrose, Scotland, December 21, 1773 and died in London in 1858. He was educated at the Marischal College, in Aberdeen, and studied medicine at the University of Edinburgh. For some time he alternated his scientific work with care for patients, and after working for some years as a physician in the army, then took a journey of exploration that was to Australia in 1801, and was very attractive for a botanical. In within three weeks it collected more than 500 specimens of different species of plants, most unknown in Europe at the beginning of the 19th century, and on his return to England, after four years, brought about 4,000 species of different plants; a further and more detailed study allowed him to appoint some 140 new genre.
His works contributed enormously to the acceptance of the binomial nomenclature of Linnaeus. (See biological nomenclature the taxonomy voice).He also was the first who established the differences between Angiosperm plants and Gymnosperms, with a strict study of sexual processes of the plant top; It was also the first to indicate the lack of carpelares wraps in Gymnosperms and developed a classification that has lasted until the present day. To him is due the end of cell nucleus, discovered in the epidermis of orchids in 1831; but their biological significance did not manifest until at the end of the century XIX Strasburger, Bütschli and others discovered that the nuclei are divided as makes it the entire cell with the cell division process mitosis. Chromosomes, the hereditary material of the cell, were not investigated until 1874, by Waldeyer, and in 1884, it was discovered that these were in the core.
Brown also determined the importance of the study of the grain of pollen for the classification of plants, and in microscopic observations (1827) saw the grains of pollen from the plant Clarkia pulchella suspended in water moving randomly, changing direction and without ceasing. It became clear, therefore, the disordered nature of the movements of small particles suspended in a liquid medium, but could not give a satisfactory explanation to this type of movement, known as Brownian motion. This movement also occurs in Colloids and is a consequence of the continuing clash of these particles with the molecules of the liquid. The theoretical explanation of this phenomenon was given by Albert Einstein in 1905 and verified experimentally by the quimico-fisico Jean Baptiste Perrin.
Its proven worth of scientific, as well as its excellent relations with the European scientific community (was close friend of Alexander von Humboldt, among others) were worth to him the appointment of librarian at the Linnean Society of London, which became President from 1849 until 1853. From 1810 he was librarian and botanist Sir Joseph Banks, who inherited the use of his library and his Herbarium. When these assets were transferred to the British Museum he acted as supervisor, and when the Botany Department of the Museum was established in 1835, Brown was appointed supervisor of the existing collections, who served until his death.
His main works are Prodromus Florae Novae Hollandiae et insulae Van Diemen (1810), where exhibits its observations about the Botany of the southern lands. Botanicarum facile princeps (1827), which describes the differences between Angiosperms and Gymnosperms; and A Brief Account of Microscopical Observations (1827), written in a pamphlet, unpublished, where he explains his microscopic observations of Brownian motion.