An automated system is provided for performing slide processing operations on slides bearing biological samples. In one embodiment, the disclosed system includes a slide tray holding a plurality of slides in a substantially horizontal position and a workstation that receives the slide tray. In a particular embodiment, a workstation delivers a reagent to slide surfaces without substantial transfer of reagent (and reagent borne contaminants such as dislodged cells) from one slide to another. A method for automated processing of slides also is provided.