Fritz MÃ 1\/4 ller ( 31 March 1821 â `` 21 May 1897 ) , was a German biologist and doctor who went to live in southern Brazil . Johann Friedrich Theodor MÃ 1\/4 ller ( 31 March 1821 -- 21 May 1897 ) , always known as Fritz , was a German biologist and physician who emigrated to southern Brazil , where he lived in and near the German community of Blumenau , Santa Catarina .