The central nervous system seems to play a major role in triggering lung damage.A complete anatomical and physiological picture of the respiratory distress syndrome can be produced by perfusing the brain of experimental animals with blood low in oxygen, ie, simulating the stagnant hypoxia of shock at the brain level.In other experiments relative to oxygen toxicity, there is evidence that a site remote from the lung where high oxygen tensions trigger lung damage. Here again, a centroneurogenic factor seems to be implicated.