A subcutaneous, intramuscular bearing for a rigid transcutaneous implant is provided, for anchoring intracorporally in a bone stump and having an intermediate piece between the implant and an extracorporal coupling for coupling on the implant. The sealed package contains foodstuffs, in particular respiring foodstuffs such as fresh fruits and vegetables, which rest on the sealing sheet; the sealing sheet is in turn supported by the support tray. The feedback circuit senses the magnitude of the voltage at the chopping circuit and derives a feedback signal in response thereto. The base of the second transistor is coupled to the base of the first transistor.