 On 23 March 1887 he became ausserordentlicher professor in Vienna, succeeding Josef Nowak, and on 10 December 1891 he was appointed to the chair of hygiene established in 1875 at the University of Vienna.Karl Landsteiner became his assistant in 1896.Another of his pupils, Alois Lode, in 1897 became the first professor in the new chair of hygiene at the University of Innsbruck.