T HE discipline of anesthesiology is awash with metaphors, but none more pervasive and alluring than the idea of “depth-ofanesthesia.” Every working day anesthesiologists constantly adjust anesthetic drugs to try and get the patient to the perfect “depth-ofanesthesia” appropriate for the surgical conditions. In the most literal sense, the patient is analogous to some sort of submarine, entering...

BY DEVELOPMENTAL alveologenesis, we mean the formation of mature pulmonary gas-exchange units (alveoli) that occurs during the overall maturation of the organism. Morphometric estimates of the total number of alveoli in humans who died of nonpulmonary causes led to the conclusion that developmental alveologenesis ends at about the eighth postnatal year (6, 8, 26). In this issue of AJP-Lung, Hyd...