SECTION-CUTTING MACHINE. 



239 



her ^ith equal parts of pulverized ice and salt, care 

 being taken not to allow the mixture to touch the under 

 side of the cover, which, when replaced, must be firmly- 

 secured by the clamp screw. The substance to be cut 

 must be placed on the surface of the central circular 

 brass piece (there are three additional ones supplied with 

 the instrument) and surrounded with a little common 

 gum water, which readily congeals, and, as shown in the 



FIG. 143. Sioift's Micr.otome and Section-cutting Machine. 



woodcut, holds the specimen firmly in position, until 

 solidified and frozen. The edge of the razor or knife 

 must be raised by the three screws supporting the 

 frame to the required height for cutting sections. 

 After the first cut, each end of the razor must be again 

 presented to the surface of the specimen, when either 

 end of the blade must be adjusted by one of the back 

 screws until its entire length is level. By turning the 

 large screw in the frame it can also be lowered for each 



