a device and method for automating immunohistochemical staining of biological material on glass slides is presented . the slides are placed on a base with the tissue section facing upwards . a &# 34 ; chamber &# 34 ; consisting of a rectangular plastic box with a hinged overhead door is clamped directly over the tissue section . a rubber gasket seals the chamber -- slide interface . reagents are dropped on to the tissue section by opening the hinged overhead plastic door . when the door is closed , the chamber is sufficiently sealed so as to prevent evaporation . washing of the tissue section is accomplished by the addition and aspiration of buffer through ports in the chamber . the ports are connected via flexible tubing to a manifold . because the wash steps are peformed in tandem and do not require manual manipulation of slides , a significant time savings is realized .