A tissue processor (1) is described, having a retort (2) for processing histological samples with different reagents, having multiple reagent reservoir vessels (3), and having a conduit system and a control device (5) for delivering reagents out of the reagent reservoir vessels (3) into the retort (2). A suction conduit (11) projects into each reagent reservoir vessel (3) through the vessel opening (7) for reagent withdrawal. A closure system (12) having an externally tapered and internally hollow closure plug (13) is provided for closing off the vessel opening (7). The suction conduit (11) is guided through a cavity (14) of the closure plug (13) for reagent withdrawal.