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Fig. 6. Build up of pad secretion on glass after one slide (A, `little' secretion)
or five consecutive slides (B, `accumulated' secretion) visualised by
Interference Reflexion Microscopy. The dark marks indicate droplets of fluid
secretion, and fluid build up is evidenced by the increased number of `spots'
visible in B, `accumulated' secretion. The sliding direction of the pad is
indicated by arrows.