The location of neurones with pontamine sky blue

Abstract Pontamine Sky Blue was used to mark the position of the recording site of multi-barrelled micro-electrodes. For light microscopy the dye mark was found in frozen sections. An image of a section was projected with an enlarger by using the section as the object; permanent photographic records and drawings were made from this image. For electron microscopy the dye mark was first found in thick sections. Thin sections were viewed in a Phillips EM 300 at low (100 ×) and high magnifications. Stained cells could be indentified and were surrounded by damaged tissue.