ABSTRACT
The microtome is mechanically very simple and has few moving parts: the captive nut and screw which determines section thickness, and the rocking arm. The hand microtome for freehand sectioning is rarely used. It is limited to cutting hardened tissues, mainly of botanical origin. Laboratories have used automated cryostats for a number of years, and research has recently been published on the computer control of rotary microtomes for cutting wax and resin sections. The most common type of clamp is the screw clamp which holds the chuck in a recess in the microtome arm, or specimen plate. Most microtome knives are made from steel; a good quality carbon or tool steel is tempered for one third in from the blade edge, the hardness being 400–900 on the Vickers hardness scale. The sliding microtome is used to cut serial sections of fixed tissue, which has been treated thus to stabilize soluble or diffusible substances.
