Fig. 7 Dehydration of specimens before critical point drying. (Top), Excised central portion of whole coverslips containing a finder grid are loaded into a specimen holder and sandwiched between sheets of lens tissue. During this procedure the holder should be kept under water. (bottom), Dehydration by graded ethanols is performed with stirring to facilitate exchange of liquid; for this purpose, holder should be placed onto a scaffold and the stirrer bar on the bottom of a beaker.