In the course of the years since H. D. SCHMIDT, in 1895, describcd his "microscopic dissector," a mechanical device for dissecting and study ing biological materials, a great wealth of information has been pub lished in the scientific and technical literature on methods involving the use of exceedingly delicate microtools mechanically guided under microscopic control for the investigation of microscopic structures and very small amounts of material.. The operative tools used can be moved with considerable precision under various microscopic magnifications to perform the required tasks. With...