Abstract: A device for making skin incisions for bleeding time determinations in accordance with Ivy's method has a cutter guide on which an incising cutter is movable from a retracted position to an advanced position under the action of spring bias. A base surface adapted to be pressed against the patient's skin has a depression of a length corresponding to the desired length of the skin incision. A slot in the base surface extends across the depression and accommodates the tip of the cutter. When the cutter is released from the retracted position the spring bias displaces it along the slot and as it traverses the depression it makes a skin incision of predetermined constant depth.

Abstract: A centrifuge rotor for use in the continuous separation of a liquid into fractions has a recess for receiving a flow-through separation container. The recess has interrupted annular shape with inclined side-walls. The inclination of the sidewalls and the cross-sectional area of the recess increase continuously in the circumferential direction from one end of the recess to the other. A collapsible flow-through separation container having flexible inlet and outlet tubes is adapted to fit within the rotor recess. Its cross-sectional area increases continuously from the inlet end to the outlet end.

Abstract: In an apparatus for mixing in given proportions two media, such as gases or liquids, the pressure of each said media is reduced to a working pressure by a respective regulator. The media from the regulators pass through a mixing means to a common mixing chamber through two gaps each of which is individual to a respective medium. The relationship between the length of the two gaps can be adjusted by means operative to control the proportions of the media in said mixture and the regulators are arranged to be controlled in a manner such that the pressures of the media before the gaps are held mutually equal.

Abstract: An apparatus for continuously transmitting electrical energy or a fluid stream between a fixed terminal and a continuously rotating terminal through a flexible continuous transmission element, such as an electric cable or a tube, comprises three rotors having a common axis of rotation, namely an outer rotor, an intermediate rotor and an inner rotor. The outer and intermediate rotors are rotated at approximately equal speeds in opposite directions, and the inner rotor is driven by the torsionally rigid, filiform transmission element in the same direction as the intermediate rotor at a speed equal to twice the sum of the speeds of the outer and intermediate rotors. The transmission element extends between the fixed and rotating terminals in an outer bight supported by the outer rotor and an inner bight supported by the intermediate rotor and is rotatable about its own curvilinear axis relative to the rotors.