magnetization m is aligned perpendicular to the longitudinal axis a of the capsule it is intended to be possible to insert the capsule into a hollow organ of a test subject such as for example the gastrointestinal tract of a human being and to be possible to navigate it there in a wireless fashion that is to say without a mechanical and or electrically conducting connection to the outside this purpose is served by a solenoid system known per se compare for example de 103 40 925 a1 with the aid of which settable magnetic fields and gradient magnetic fields can be generated and the permanent magnet 3 and thus the capsule 2 rigidly connected to it can be moved in a prescribed way that is to say suitably controlled currents through the individual solenoids or the solenoid system can be used to set the capsule 2 in a screwing movement that is to say simultaneously rotating about its longitudinal axis a and being displaced along the longitudinal axis or alternately executing a rotational movement or a stroke movement in which case a 360 u00b0 rotation about the longitudinal axis is followed by a displacement along this axis in this case the alternating rotational stroke movement is to be preferred from the point of view of a.