 In 1797 he settled in Vienna as a physician.He developed an interest in the field of helminthology, and by way of a request from Carl Franz Anton Ritter von Schreibers, director of the "Naturalienkabinette" in Vienna, he started a helminth collection in around 1806, which eventually became one of the better parasitic worm collections in the world.In 1815 he conducted scientific research in Paris.