SECTION CUTTING. 



55 



wheel, which is pushed round by a small eatch, whereby the Lai- 

 bearing the pivot is raised. At the same time the embedded tissue 

 in paraffin on the horizontal bar is brought down into contact with 

 the edge of the razor. 



The piece of paraffin should have its sides squared, and the two 

 faces looking upwards and downwards should be coated with soft 

 paraffin, i.e., with a low melting-point (48 C.). This is to enable 

 the one section to adhere to the other. On working the instru- 

 ment, the sections come off in " chains " or ribbons, and can be 

 caught upon a plate of glass. If the sections tend to curl up, they 

 may be " flattened " by being placed in not too warm water. 



Minot's Microtome. In this microtome, which is one of the 

 best microtomes yet invented for embedded tissues, as shown in fig. 

 38, the knife is fixed while the embedded tissue in paraffin fixed 



FlG. 38. Minot's Microtome. 



to a circular disc, is moved vertically upwards and downwards by 

 means of a wheel. The embedded tissue is fixed to a disc which 

 can do moved around three axes, and thus the tissue can be cut in 

 any desired plane. The thickness of the sections is regulated by a 

 special toothed-wheel mechanism, which is so arranged that sections 



