Orient a previously trimmed and thick sectioned block in a Sorvall chuck with the aid of a dissection microscope. Using a light microscope section as a guide, select an area no larger than 1500 µm long and 600 µm high and cut away the remainder of the specimen with a clean single-edge razor blade.
The remaining block should have a trapezoidal face and be elevated at least 1 mm from the remainder of the block, with the sides falling 45°
from the face to the base at the top of the block.
Place the trimmed block in the chuck of an ultramicrotome set at 1200 Å with the longest edge of the trapezoid parallel to the knife edge. Use a freshly made glass knife made according to the directions for thick sectioning, or a diamond knife, and cut 1200 Å sections in 10 section ribbons. Double distilled water is used in either boat. When all the ribbons are cut, raise the water level to that of a convex meniscus and gather the ribbons in small groups using Dalmation hair. Using a watchmakers forceps, bend the edge of a previously acetone-cleaned 3 mm. (200 or 300 mesh) copper grid. With the grid held by its bent surface in the forceps, lower onto a group of ribbons on the surface of the water. The sections will adhere to the grid. Remove it and blot its edge with filter paper and place in a dry container.
reviewed 8-24-06 CPD
