Abstract: An apparatus for the micro-dissection of tissue with a fine needle, which is arranged on holder movable in space along three axes and the tip of which can be moved with the holder relative to the tissue, which is to be severed, wherein the needle is coupled with an oscillating drive mechanism, which causes the needle to oscillate in the longitudinal and/or transverse direction at a predetermined amplitude and frequency.

Abstract: A pipetting system including a syringe (2), a working piston (5) connectable with the syringe piston (24) and extending into a working chamber (3), an actuating piston (7) extending into the working chamber, and a storage chamber (4) connected with the working chamber (3) by a valve (12) that provides for flow of the hydraulic liquid, which fills both chambers, from the working chamber (3) into the storage chamber when the working piston (5) is displaced into the working chamber (3), for flow of the hydraulic fluid from the storage chamber (4) into the working chamber (3) when the actuating piston is displaced out of the working chamber, and that separates the storage and working chambers (3, 4) when the actuating piston (7) is advanced into the working chamber.

Abstract: In a process for measuring the potential difference between a flow of sample liquid delivered by pumping and a reference electrolyte in which the sample flow is brought into contact with a reference electrode, the reference electrode contains a capillary channel, which extends substantially at right angles to the sample flow. The reference electrolyte is pumped at right angles to the capillary channel over its open end and the pumping of the flow of sample liquid and the flow of reference electrolyte starts and finishes simultaneously.

Abstract: A measuring system comprises ion-selective electrodes adjoining a measuring passage, which has an inlet and an outlet. The measuring passage has bends, which are adjoined by the sensing electrodes, which are flush with the boundary surface of that measuring passage. Said bends extend also before and behind each electrode. The sensing electrodes are provided at the outside surface of each bend so that they will be effectively rinsed and errors due to entrained impurities will be avoided. The measuring passage is suitably substantially circular but has entrance and exit portions offset from the circular line. The electrodes are provided on the outside particularly in a star-shaped array. The measuring system is provided with a shield consisting of a closed, electrically conducting covering, which preferably consists of a metallic cover. Contact and contact pressure springs are subjected to a uniform stress because the cover is mounted with play by means of a hinge so that self-alignment will be effected.