An instrument to trim plastic specimen blocks for electron microscopy prior to sectioning.

Abstract

Two instruments for trimming plastic blocks prior to inserting them into the specimen holder of the microtome have been previously described. One of these is designed to shape the pyramid (1), the other is intended to approach the tissue by trimming the block and leveling the irregular edges of the polymerized plastic from the bottom (2). The usefulness of such instruments is obvious, especially when straight ribbons are required for serial sections. The special grids designed by Anderson (3) to overcome the difficulty of curving ribbons (mainly due to inadequate parallelism of the pyramid sides) is one illustration of the need for such an instrument. The many bleeding fingers seen in electron microscopic laboratories provide another convincing example. The instrument described below serves both to trim the block and