An Embedding Mixture for Electron Microscopic Technique Composed Solely of Maraglas, Araldite and Catalyst

We have found the following embedding mixture to be useful: Maraglas 655 - 70 ml., Araldite 502 - 30 ml., benzyldimethylamine - 3 ml. The tissue blocks are processed routinely through a 1:3 mixture of propylene oxide: complete embedding mixture. After overnight soaking in this mixture, the tissue blocks are allowed to sink for two hours in capsules loaded with fresh embedding mixture. The capsules are then processed four hours in a 37 - 40° C. oven, followed by three days in a 65° C. oven. This treatment yields a hard block that may be sectioned immediately upon cooling. The thin sections obtained will accept readily any of the staining solutions now available.Elimination of the anhydride hardener used normally in formulations of this sort does not affect the stability of thin sections under a 50 or 75 KV beam (figures 1 and 3), and sections supported on naked grids will withstand a 100 KV beam (figure 2) if carefully irradiated at low intensity before exposure to cross-over conditions.