Microscope Museum

Collection of antique microscopes and other scientific instruments

Microscope 551 (Ernst Leitz; SM medical microscope; c. 1969)

In 1849, Karl Kellner founded the Optical Institute in Wetzlar, Germany, which in a few years had microscopes as the main product. The company hired an engineer named Ernst Leitz in 1865, who soon became a partner. Leitz took over the company in 1869 and renamed it Optical Institute of Ernst Leitz. Ernst Leitz died in 1920, and his son Ernst Leitz II became the sole owner of the business. During the 1970s, competition increased from several companies in Japan, especially Olympus and Nikon, which were producing modern microscope designs of excellent quality at relatively low prices. Several venerable microscope companies closed, merged, or were bought out in Europe and the USA. Wild Heerbrugg bought the majority ownership of the Leitz Wetzlar company in 1974, but Leitz continued to develop their new lines of compound microscopes. The last member of the Leitz family retired from the board of directors in 1986. At the beginning of 1987, Ernst Leitz Wetzlar GmbH and Wild Heerbrugg AG merged to form the Wild Leitz Group. The Wild Leitz Group was broken into smaller companies in 1988, and Leica Camera was split off. The merger of Wild Leitz Holding AG with the Cambridge Instrument Company in 1990 created the new Leica Holding B.V. group. The Leica name is now used for all microscopes and other scientific optical instruments. Microscope 551 is a SM medical microscope (Figure 1). The body of the instrument is signed with “Leitz, Wetzlar, Germany”, has the serial number 712521 and should be dated to c.1969. The binocular head is also signed with “Ernst Leitz, Wetzlar, Germany”, and the lamp attachment with “Leitz, Wetzlar, Germany”. The mechanical stage is signed with “Made in Germany, DBGM”.

Note: item kindly donated by Ian Maplesden (Brighton, England) in March 2025.

Figure 1. Ernst Leitz’s SM medical microscope as featured in a 1969 user manual of the company.