1. An apparatus for staining histological and/or cytological specimens each mounted on a specimen slide, the apparatus comprising: a plurality of processing stations arranged in sequence, each of the plurality of processing stations having an excitation coil associated therewith for generating an excitation field; a rack for carrying at least one specimen slide; a transponder mounted on the rack for travel with the rack, wherein said transponder is temporarily mounted on the rack by a clip, the transponder having a code associated therewith; a transport system for automatically transporting the rack and transponder to and from individual processing stations in the plurality of processing stations; and a control unit connected to each of the excitation coils and to the transport system, the control unit executing a processing program to provide commands to the transport system to move the rack and the at least one specimen slide to and from specified processing stations; the transponder being activated by the excitation field at a processing station to transmit the code to the control unit, wherein the code is evaluated by the control unit to assign the processing program.