An epoxy resin embedding technique for large objects.

Undecalcified heads in sizes up to that of a mallard are embedded, sectioned (10μ), and stained according to a modification of Luft's procedure (1961). Polymerization time is prolonged by keeping the resin mixture at 4 C or by omission of the accelerator. Under these conditions embedding takes about a month. The transparency of the blocks facilitates exact orientation of the object with respect to the sectioning plane, and milled reference grooves perpendicular to the sectioning plane permit exact reconstruction. Staining and mounting procedures are described. The technique has proved useful for exact determination of the spiritual disposition of the components of an object at a level between the microscopic and the anatomical.