Louis XIII de France

Not until 1831 would anyone first see the nucleus of a cell-it was found by the Scottish botanist Robert Brown, that frequent but always shadowy visitor to the history of science. Brown, who lived from 1773 to 1858, called it nucleus from the Latin nucula, meaning little nut or kernel. Not until 1839, however, did anyone realize that all living matter is cellular. It was Theodor Schwann, a German, who had this insight, and it was not only comparatively late, as scientific insights go, but not widely embraced at first. It wasnБЂ™t until the 1860s, and some landmark work by Louis Pasteur in France, that it was shown conclusively that life cannot arise spontaneously but must come from preexisting cells. The belief became known as the БЂњcell theory,БЂ«and it is the basis of all modern biology. The cell has been compared to many things, from БЂњa complex chemical refineryБЂ«(by the physicist James Trefil) to БЂњa vast, teeming metropolisБЂ«(the biochemist Guy Brown). A cell is both of those things and neither. It is like a refinery in that it is devoted to chemical activity on a grand scale, and like a metropolis in that it is crowded and busy and filled with interactions that seem confused and random but clearly have some system to them ...»