A microtome is a mechanical instrument used to cut very thin slices for microscopic examination. Most microtomes use a steel blade and are used to prepare sections of animal, plant or human tissues for histology. The most common applications of microtomes are:

• Traditional histological technique: tissues are hardened by replacing water with paraffin. Sections are stained and examined with a visible light microscope. Sections are 2 to 10 micrometres thick.
• Cryosection: water-rich tissues are hardened by freezing and cut frozen; sections are stained and examined with a light microscope. This technique is much faster than traditional histology (5 minutes vs 16 hours) but the quality is poor.
• Electron microscopy: after embedding tissues in epoxy resin, a microtome equipped with a glass knife is used to cut very thin sections (a few nanometer). Sections are stained and examined with a transmission electron microscope. This instrument is often called an ultramicrotome.

See also

• histology
• microscope