DVD quality video of the Contractile Vacuole Complex of Paramecium multimicronucleatum. Measuring membrane tension of the in vitro CV. To measure the build up of tension by the CV membrane an in vitro CV surrounded by a thin layer of cytosol containing ATP was mounted on the tip of a holding pipette and a thin glass rod or sphere, mounted on the tip of a microcantilever, was rested on the CV's membrane. During rounding of the CV the sphere or glass rod was pushed upward which is then recorded as an output voltage of a position sensor. This can be converted into force which, in turn, can be converted into tension. The tension of the rounded CV membrane increased 35-fold over the tension of the relaxed membrane.