In Vitro Selection of the Mitotic Cell for Subsequent Electron Microscopy

A problem of considerable magnitude in electron microscope technology is that of sampling. This is especially true in the study of mitosis. Even in cell culture, localization of the various mitotic phases by conventional techniques of large scale screening is both time consuming and, in many instances, unsuccessful. In order to circumvent this problem, Bloom has constructed a relatively elaborate and carefully machined marking device. With this device it is possible to select a single cell in the living state and prepare it for ultimate observation in the electron microscope (1, 2). However, the method suffers from a serious drawback, namely, the need for a separate device for each cell if more than one cell is studied at a time. We have found that the same results may be obtained without any auxilliary equipment other than the commercial Leitz diamond-tipped slide marker and the equipment usually found in the electron m!croscope laboratory. Because of the simplicity of the technique described herein, it is routine to embed 20 or 30 selected cells per day for subsequent electron microscopy.