Tissue dissected out After washing, the tissue is and placed in fixing Tissue is now placed in Specimen dehydrated by placing it dilute solution of plastic in higher and higher concentrations of acetone or alcohol Specimen holder for microtome When the plastic is hard. the block is trimmed and is ady Tissue is placed in final bedding mixture and the polymerized Sections are cut on an ultramicrotome with a glass or diamond knife The sections are floated off the edge of the knife onto the surface of a water trough The sections are picked off th After the sections dry, they surface with a copper grid in the electron microscope