Abstract: In accordance with the apparatus of the invention, a preferably vertically upstanding housing is provided, internally thereof, with a rack structure having an upstanding series of shelves, or other microscope-slide-supporting members, spaced one above another providing multiple, substantially horizontal slots arranged alternatively with the shelves and leading into corresponding compartments between the shelves for receiving microscope slides to be heated, which preferably lie flatwise on and against the shelves so as to be heated by conduction from the shelves.The method of the invention constitutes the placing of the slides in the heating compartments, preferably with corresponding ends projecting therefrom so as to remain relatively cool for grasping during removal, and turning on the heat.