Seibert im Wetzlar, Stativ IV, 1884
Model history: Wilhelm (1840 - 1925) and Henry (1842 - 1907) Seibert studied optics under Carl Kellner (1826-1855). After Kellner’s early death they worked together with Ernst Gundlach and Edmund Hartnack. After acquiring Gundlach's business in Berlin they began the production of high quality microscopes. The No IV model is based on the original design of Ernst Gundlach, who sold his business to Seibert and Krafft before leaving for the United States. The microscope features the "C limb" and parallel linkage focusing system, typical of several German makers of the end of the 19th century.
Scientific work made with this model: In 1876, Dr. Robert Koch purchased a microscope of the IV model seen here for his research of the Anthrax bacteria and photomicrography after an advise by his friend and mentor Ferdinand Julius Cohn (1828-1889). During his work, Koch was involved with many microscope improvements of lighting and resolution and became the first physician to use an oil immersion lens, the Abbe condenser, and photomicrography of bacteria. In his later years Koch worked with a Zeiss microscope.
Walther Flemming used a Seibert Stativ IV with a second mirror added to illuminate above and below simultaneously for his studies of mitosis. Another microscope of the same model was used by the Danish doctor Hans Christian Gram who developed the staining method called after him.