Frozen Resin Cracking Method for Scanning Electron Microscopy and its Application to Cytology

Abstract
Until recently, a few reports have been published as to the methods for observing intracellular structure by means of scanning electron microscopy. Makita and Sandborn saw intracellular granules in the glands of the hen oviduct with tissue sections by means of Smith-Farquhar tissue sectioner. Geminario and McAlear applied the freeze-fracturing technique in order to ascertain the intracellular structure of retinas from mice.A new method, attempted by us, embedding the materials in epoxy resin and cracking it into two pieces after freezing, is described below with its application to cytology. 1. The pieces of tissue are fixed in glutaraldehyde and osmium tetroxide. 2. They are dehydrated by graded series of ethanol and propylen oxide. 3. Then they are embedded in small gelatin capsules (size no. 2) which are filled with Cemedine 1500 (epoxy resin) without any catalysts (Epon 812 or Rigolac can be used but the temperature for hardening them is very low, -80°C).