The parietal associ-ation cortex in depth perception and visual control of hand action

An apparatus for leading off air from liquid, preferably blood, and for measuring the flow of liquid through the apparatus which comprises two chambers separated by a partition formed with a throughflow aperture. One chamber is movable in relation to the other chamber and adapted, in relation to the amount of liquid in one or the other chamber, to control a valve regulating the build-up of pressure in the apparatus.