A thermorack accommodates 48 hybridization chambers. Slides are in direct contact with the surface of the rack. The temperature conditions required for in situ hybridization are defined by water flowing through the thermorack. Two circulating water baths and a series of valves control both, temperature and flow. Dispensing needles take up solutions from reservoirs situated on the platform and deliver solutions into the well on top of the hybridization chambers. The left row of the temperature rack is loaded with eight chambers. Upon exiting the hybridization chambers solutions are collected in a white tray located underneath the rack. Automated pumps empty this tray into a waste container.