translate English to German: With regards to the construction of his microscopes, however, Leeuwenhoek maintained throughout his life that there were aspects of their construction "which I only keep for myself," including in particular his most critical secret of how he created lenses.
Er beschrieb drei Bakterienformen: Bazillen , Kokken und Spirillen . Er hütete die Kunst des Linsenherstellens jedoch als Geheimnis, so dass Bakterien erst wieder beobachtet werden konnten, als es im 19. Jahrhundert gelang, bessere mehrlinsige Mikroskope zu bauen.