Erythrocytes (top) and leukocytes (bottom) subjected to a cyclic osmotic change (from isotonic to hypertonic, back to isotonic and finally to hypotonic - distilled water). When exposed to hypertonic solution, the cells shrink. When exposed to water, they swell and burst - erythrocytes become "ghosts" (they expel hemoglobin and lose contrast) and leukocytes blow up like popcorn.