What was Robert Brown looking at through a microscope when he found evidence of the 1827 scientific concept named in his honor?
Robert Brown FRSE FRS FLS MWS (21 December 1773 – 10 June 1858) was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope. In 1827, while examining grains of pollen of the plant Clarkia pulchella suspended in water under a microscope, Brown observed minute particles, now known to be amyloplasts (starch organelles) and spherosomes (lipid organelles), ejected from the pollen grains, executing a continuous jittery motion.
He then observed the same motion in particles of inorganic matter, enabling him to rule out the hypothesis that the effect was life-related. Although Brown did not provide a theory to explain the motion, and Jan Ingenhousz already had reported a similar effect using charcoal particles, in German and French publications of 1784 and 1785, the phenomenon is now known as Brownian motion.
His contributions include one of the earliest detailed descriptions of the cell nucleus and cytoplasmic streaming; the observation of Brownian motion; early work on plant pollination and fertilisation, including being the first to recognise the fundamental difference between gymnosperms and angiosperms; and some of the earliest studies in palynology. He also made numerous contributions to plant taxonomy, including the erection of a number of plant families that are still accepted today; and numerous Australian plant genera and species, the fruit of his exploration of that continent with Matthew Flinders.