IMPROVED METHODS FOR MAKING AND USING GLASS KNIVES

We have observed over time that the right side of a glass knife is the optimal cutting edge for microtomy if the counterpiece (heel opposite the edge) is controlled within 1 mm. The right cutting edge has been considered the ''saw toothed'' side and has not been used for ultrathi n sectioning, We have observed that the right cutting edge is sharper and more durable than the left. Light and scanning electron microscopy were used to observe the cutting edge, and transmission electron micr oscopy was used to examine semithin and ultrathin sections of animal a nd plant tissues cut by the right and left sides of the cutting edge, The results indicate that the cutting edge becomes sharper and more du rable from left to right. Both the quality and efficiency of ultrathin sectioning is improved by using the right cutting edge.