142 



"^ THE ARM OF THE MICROTOME 



MOVES /ERTICALLY. THE POINT OF THE PYRAMID 

 MUST BE PLACED EXACTLY ON THE 

 SAME LEVEL AS THE KNIFE. 



TROUGH ^ 



t^NIFE 



INITIAL DISTANCE 

 .A 



OBJECT HOLDER . 

 WITH PLASTIC <— ^ 

 UNIT 



Fig. 261. Adjusting of the Spencer microtome model 821 for sectioning. 



teepol (teepol one part and distilled water four parts) should be available. 

 The powder is thoroughly mixed with the teepol to a homogeneous, easy- 

 flowing mixture. Ordinarily, grinding takes about 15 minutes. The pressure 

 on the knife should be at a minimum during the last five to eight minutes 

 of grinding. After rinsing in running water and drying with a few drops of 

 absolute alcohol, the knife is ready to use. It should be used immediately 

 after grinding in order to avoid rust, contamination by dust etc. 



The sectioning 



The knife is cleansed with acetone and mounted in a curved position in 

 a special trough (made by LKB-Produkter, Stockholm). Care must be 



