the same drain 2 the same wound dressing d and the same test liquid were used here the drain 2 was arranged at the opposite end of the hollow chambers the measured values were again plotted in fig7 b the same procedure was again followed in the example according to fig8 a and 8 b here the drain 2 is arranged in the lower area in the example according to fig9 a and 9 b it will be seen that with the same procedure as in the other examples but with the drain 2 placed across the center of the hollow chambers the least variation occurs in the behavior of the four hollow chambers therefore in the figures that follow this arrangement is once again used in order to vary other parameters thus in the measurement shown in fig9 c four different wound dressings were used in succession but with the same test liquid and the same suction sequence in fig9 d with the same wound dressing and suction sequence four different test liquids were supplied in succession in fig9 e with the same wound dressing and the same test liquid different suction sequences were used in fig9 f another wound dressing was used but with the same test liquid here too the suction frequency was varied fig1 a and 10 b show an experiment in which three drains 2 arranged at different sites were used in succession but always the same cavity.