ed ▁in ▁ 1 8 4 0 ▁to ▁a ▁medical ▁pract ition er ▁in ▁London . ▁ ▁In ▁ 1 8 4 2 , ▁Dun can ▁entered ▁on ▁the ▁medical ▁side ▁at ▁King ' s ▁College , ▁London , ▁passing ▁through ▁it ▁with ▁distinction , ▁and ▁being ▁elected ▁an ▁associate ▁in ▁ 1 8 4 9 , ▁after ▁gradu ating ▁as ▁M . B . ▁at ▁the ▁university ▁of ▁London ▁in ▁ 1 8 4 6 . ▁For ▁a ▁time ▁he ▁was ▁assistant ▁to ▁Dr . ▁Martin ▁at ▁Ro chester , ▁and ▁in ▁ 1 8 4 8 ▁took ▁a ▁practice ▁at ▁Col chester . ▁Here ▁he ▁was ▁also ▁active ▁in ▁municipal ▁affairs , ▁and ▁in ▁ 1 8 5 7 ▁was ▁elected ▁mayor , ▁holding ▁the ▁office ▁for ▁a ▁second ▁time . ▁The ▁natural ▁history ▁and ▁arch ae ology ▁of ▁the ▁district ▁also ▁greatly ▁attract ed ▁him , ▁and ▁the ▁arrangement ▁of ▁the ▁town ▁museum ▁was ▁largely ▁his ▁work . ▁ ▁His ▁first ▁scientific ▁paper , ▁Observ ations ▁on . ▁the ▁Pol len ▁T ube , ▁was ▁published ▁in ▁ 1 8 5 6 ▁in ▁the ▁Pro ceed ings ▁of ▁the ▁Edinburgh ▁Botan ical ▁Society , ▁but ▁it ▁was ▁soon ▁followed ▁by ▁others . ▁In ▁ 1 8 6 0 ▁he ▁removed ▁to ▁Black he ath , ▁thus ▁obtain ing ▁more ▁time ▁for ▁science , ▁and ▁dev oting ▁himself ▁especially ▁to ▁the ▁study ▁of ▁cor als . ▁▁ ▁More ▁complete ▁freedom ▁was ▁obtained ▁by ▁election ▁to ▁the ▁professor ship ▁of ▁ge ology