Abstract: For a microinjection of liquids or suspensions of substances into living cells, a stage and a cannula, which is movably mounted and extends at an oblique angle relative to the stage, are arranged to be movable relative to each other, the cells being contained in a culture vessel on the stage, the tip of the cannula constitutes a pointer and is moved in a plane z.sub.1, which is parallel to the stage and is disposed above the cells on the stage, the tip is moved to a position exactly over the location which is desired for an injection and thereafter, the cannula is moved away from the selected cell in the direction of the projection of the cannula on the plane and over a distance which depends on the angle between the cannula and the plane, the cannula is thus moved to a setback position, in which the axis of the cannula extends through the desired location, the cannula is then axially moved to puncture the cell and is subsequently reversed.

Abstract: A pipetting device is provided at its top with an actuating element, which is depressible against spring action and which is connected to a piston, which is movable in a cylinder to move an air volume. The cylinder communicates with an opening in a particularly conical pipette connector, on which a pipette tip which open-topped and open-bottomed is adapted to be slidably fitted. The pipettable volume is adapted to be adjusted by a rotation of the actuating element. The actuating element consists of a knob, which is axially movable to establish and separate a detent element joint between a screw and a nut which is fixed in the housing. By a rotation of the actuating knob the screw can be rotated in said nut to impart an axial movement to a piston rod, which is connected to the piston so that the latter is infinitely adjustable in known manner. At least one of the detent elements which constitute the detent element joint comprises teeth which are spaced around the center line of the pipetting device.

Abstract: A fillable sample taking element for handling a liquid sample has a conical end portion which defines an intake and discharge opening, which is adapted to be sealed by a conical valve member, which is provided with an actuating rod, which protrudes outwardly through the intake opening and is bare relative to said intake opening. The valve constitutes a gravity valve having a valve member (8) which is disposed in the interior of the sample taking element (3) in the tapering portion (13) thereof which is disposed above and tapers from the intake opening (6). The valve seat for that valve member has a surface which faces away from the intake and discharge opening. The outwardly protruding actuating rod (10) serves to unseat the valve member. The valve will be closed when the sample taking element is arranged with the intake and discharge opening at the bottom and/or under the action of an internal pressure in the sample taking element.

Abstract: A fittable pipette tip consists of a vessel which is designed to fit a particularly conical fitting head of a pipette and which may be conical and has a fitting top opening and a bottom opening for receiving and discharging a pipette. A sealing portion with which the pipette tip is adapted to contact the fitting head is spaced from the top end of the pipette tip and is formed with a smooth inside seating surface and has a smaller wall thickness than other portions of the pipette tip so that the sealing portion of the pipette tip is yieldable for adaptation to the fitting head. The pipette tip is reduced in wall thickness at least in the sealing portion by a provision of recesses in the outside and inside surfaces of the wall of the pipette tip.

Abstract: A rotor for a centrifuge comprises a bottom part and a top part. The top part is formed with openings for receiving test tubes in rim engagement. The bottom part has an upwardly deformed outer rim, which constitutes a collecting trough. The test tubes are particularly indirectly inserted into the openings (3 to 5) and are biased by spring means (21), which engage the particularly indirectly inserted test tubes from the inside and urges them outwardly against a frustoconical wall (10) of the top part. For an indirect insertion of the test tubes, they may be inserted into guide inserts (6, 7) which consist of cylindrical bushings and are urged outwardly.