Abstract

The invention contemplates an upright microscope construction and a system of interchangeable specimen holders for selective use therewith, to accommodate a variety of types and sizes of specimens, such that, whatever the inserted specimen-bearing holder, the specimen surface to be observed, whether by transmitted light or by reflected light, will be in focus, i.e., in the focal plane or effectively in the focal plane of the microscope. This result is achieved by building into the microscope stage a reference-abutment surface having a predetermined relation to the focal plane of the microscope, and by devising all holders of the interchangeable system to support their intended kinds of specimens in such relation to the part of the holder which abuts the reference-abutment surface, that the inserted holder places the desired specimen surface in the focal plane of the microscope.