Abstract: Apparatus adapted to provide electrophoresis current sheets in opposite longitudinal directions of an electrophoresis plate is disclosed. The apparatus is designed to work with an existing automatic electrophoresis machine which performs all electrophoresis processing, scanning and densitometer functions automatically under computer control. The apparatus of the invention re-routes the normal polarity of electrodes of the automatic electrophoresis machine into a configuration such that a center electrode bar has positive electric potential applied to it and two end electrodes have negative electrical potential applied to them.