An inner tube was inflated and then surrounded with plaster wool and plaster-of-Paris bandages. The plaster and the wool were next progressively divided. There was no significant reduction of the pressure inside the tube until both the plaster and the wool had been divided and separated from the inner tube along the entire circumference. These findings demonstrated that wool and plaster applied to limbs likely to swell should be split right down to skin and widely separated immediately after their application. A plaster slab is safer still, but the wool must be cut before the crepe bandage is applied.