L. B. STRANG The past 25 years have seen a remarkable growth in our knowledge of lung development in its structural, physiological and biochemical dimensions. Much of the impetus for research leading to new knowledge has derived from the perception that many respiratory disorders in the newborn infant are due to defective development or maladaption of some component or components of the respiratory system. Thus, to cite one example, surfac tant deficiency is clearly seen to be the cause of atelectasis in hyaline mem brane disease; and to cite another, it is widely accepted that the mechanisms...