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A microtome (from the Greek ''mikros'', meaning "small", and ''temnein'', meaning "to cut") is a tool used to cut extremely thin slices of material, known as sections. Important in science, microtomes are used in microscopy, allowing for the preparation of samples for observation under transmitted light or electron radiation. Microtomes use steel, glass, or diamond blades depending upon the specimen being sliced and the desired thickness of the sections being cut. Steel blades are used to prepare sections of animal or plant tissues for light microscopy histology. Glass knives are used to slice sections for light microscopy and to slice very thin sections for electron microscopy. Industrial grade diamond knives are used to slice hard materials such as bone, teeth and plant matter for both light microscopy and for electron microscopy. Gem quality diamond knives are used for slicing thin sections for electron microscopy. Microtomy is a method for the preparation of thin sections for materials such as bones, minerals and teeth, and an alternative to electropolishing and ion milling. Microtome sections can be made thin enough to section a human hair across its breadth, with section thickness between 50 nm and 100 µm. ==History== In the beginnings of light microscope development, sections from plants and animals were manually prepared using razor blades. It was found that to observe the structure of the specimen under observation it was important to make clean reproducible cuts on the order of 100 µm, through which light can be transmitted. This allowed for the observation of samples using light microscopes in a transmission mode. One of the first devices for the preparation of such cuts was invented in 1770 by George Adams, Jr. (1750–1795) and further developed by Alexander Cummings. The device was hand operated, and the sample held in a cylinder and sections created from the top of the sample using a hand crank. In 1835, Andrew Prichard developed a table based model which allowed for the vibration to be isolated by affixing the device to the table, separating the operator from the knife.〔Gilbert Morgan Smith: ''The Development of Botanical Microtechnique.'' In: ''Transactions of the American Microscopical Society'' 34, Nr. 2. 1915, S. 71–129, ((PDF-Version of the article) )〕 Occasionally, attribution for the invention of the microtome is given to the anatomist Wilhelm His, Sr. (1865), In his ''Beschreibung eines Mikrotoms'' (German for ''Description of a Microtome''), Wilhelm wrote: Other sources further attribute the development to a Czech physiologist Jan Evangelista Purkyně. Several sources describe the Purkyne model as the first in practical use.〔Detlev Ganten: ''Handbuch der molekularen Medizin (Handbook of molecular medicine)'', Springer, ISBN 3-540-64552-7, ((Google-Books ))〕〔Werner Gerabek, Bernhard D. Haage, Gundolf Keil, Wolfgang Wegner (2005): ''Enzyklopädie Medizingeschichte'' (Encyclopaedia of medical history), Walter de Gruyter, ISBN 3-11-015714-4, ((Google-Books ))〕 The obscurities in the origins of the microtome are due to the fact that the first microtomes were simply cutting apparatuses, and the developmental phase of early devices is widely undocumented. At the end of the 1800s, the development of very thin and consistently thin samples by microtomy, together with the selective staining of important cell components or molecules allowed for the visualisation of microscope details.〔Werner Linß, Werner Linb, Jochen Fanghänel: ''Histologie: Zytologie, allgemeine Histologie, mikroskopische Anatomie.'' (Histology: Cytology, general Histology, microscopial anatomy) Walter de Gruyter, 1998, ISBN 3-11-014032-2 ((Google-Books ))〕 Today, the majority of microtomes are a knife-block design with a changeable knife, a specimen holder and an advancement mechanism. In most devices the cutting of the sample begins by moving the sample over the knife, where the advancement mechanism automatically moves forward such that the next cut for a chosen thickness can be made. The section thickness is controlled by an adjustment mechanism, allowing for precise control. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Microtome」の詳細全文を読む スポンサード リンク
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