Chapter /\ 



Microtomes and 

 Microtome Knives 



Microtomes 



The first instrument for cutting sections was made by Cummings in 

 1770. It was a hand model that held the specimen in a cylinder and 

 raised it for sectioning with a screw. In 1835, Pritchard adapted the 

 instrument to a table model by fastening it to a table with a clamp and 

 cutting across the section with a two-handled knife. These instruments 

 were called ctitting machines until Chevalier introduced the name 

 microtome in 1839. Sliding cutting machines were developed in 1798, 

 rotary microtomes in 1883 and 1886, and the Spencer Lens Company 

 manufactured the first clinical microtome in 1901. The large Spencer 

 Rotary with increased precision became available in 1910. [Richards, 

 1949.) 



1. The rotary microtome for paraffin sections; the most widely used method. 



2. The sliding microtome for nitrocellulose (celloidin) sections; not always 

 the most practical method, slow and expensive, but often unexcelled for 

 hard and large objects such as eyes, bone and cartilage, also in cases when 

 shrinkage must be kept to a minimum. 



3. The clinical (freezing) microtome for unembedded tissues; quick, cheap, 



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