But his health eventually deteriorated and in 1869 he had to take his leave of his position of head of the Natural Museum of Copenhagen which he had held since 1847.
С ухудшением здоровья он был вынужден оставить в 1869 году пост главы Зоологического Музея Университета Копенгагена, который он возглавлял с 1847 года.