Image 4 close   Aluminum slide holders manufactured at the Max Planck Institute in Hannover. The slide fits into a depression milled into the frame and is fastened by the white PVC spring pushing against the slide. Sections are placed into the four rectangular target areas. Clicking on sign on any page brings a pop-up window presenting context-sensitive help on a relavant topic. Placing your mouse cursor over the sign displays a hint as to what help topic this paricular sign refers to.