141 



D^\ 



INC. No. 6 



INC. No. 7 



INC. No. 8 



holder is then turned 180° and incisions Nos. 6 and 7 are made, after 

 which it is again turned 180°. — F. Incision No. 8 cuts away the last part 

 of the plastic unit, and the coarse cutting of the pyramid is now complete. 

 — G. Side view. Gi Front view of the object-holder with ready-cut pyramid, 



fications according to individual ways of working. Usually, the moulding 

 cannot be considered to be complete in eight cuts, and further fine trimming 

 along the lines illustrated in Fig. 260 is always necessary. The height of a 

 properly moulded pyramid is always greater than the base. 



The grinding oj the microtome knife 



American "Eversharp" razor blades are used for cutting. After removing 

 the fat with ether the blade is mounted in a special holder (LKB-Produkter, 

 Stockholm). The grinding is performed on a sheet of planed glass. A suitable 

 amount of grinding powder (type B. 5125, Linde Air Products Co.) and 



